MOLECULAR GENETICS UTOLEDO QIAN CHEN

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albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). two paretns with normal pigmentation have an albino child -what is the probability that their next three children will be an albino?

(1/4) x (1/4) x (1/4) = 1/64

(1/4) x(1/2) = 1/8

Thomas Morgan

(1911) observed unusual phenotypic ratios when crossing individuals with two X-linked genes.

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. (a) What is the probability that their next child will be albino? (b) What is the probability that their next child will be an albino girl? (c) What is the probability that their next three children will be albino?

(a) 1/4 (b) 1/4 X 1/2 = 1/8 (c) 1/4 X 1/4 X 1/4 = 1/64

In a three-point mapping experiment, what three general classes of offspring are expected (assuming crossovers occur)? (b) How many different genotypic classes are expected?

(a) Noncrossovers, single crossovers, double crossovers (b) 8

why do linked genes no undergo independent assortment?

-the alleles ar all loci of one chromosome should be transmitted as a unit -no crossover -only parental -parental gametes formed in equal proportions

which of the following are general categories of mutations select all that apply -lethal -conditional -behavioral -dna -protein

-lethal -conditional -behavioral

The Human Genome Project is an international effort to determine the sequence of the 3.3 billion base pairs in the haploid human genome.

Answer: True

Bacteria that are in a particular physiological state to become transformed are called ________.

Answer: competent

t/f in a typical PCR, primers are used to cleave specific regions of the DNA template

false

t/f in humans, no genes are larger than 2 kb

false

if you know the phenotype, you can determine the genotype by performing crosses to a ___________ __________ plant

homozygous recessive

what disease/syndrome is this? CAG repeats, poly-glutamine tract

huntington and spinobulbar muscular atrophy

what is an example of late-onset genetic disease in humans?

huntington's disease

in addition to highly repetitive and unique DNA sequences, a third category of DNA sequences exists. what is it called/what type of elements are involved

moderately repetitive DNA, SINEs, LINEs, and VNTRs

_________ are usually ~50 repeats in clusters and can be di, tri, tetra, or pentanucleotide repeats that are used in forensics

microsatellites

Under what condition(s) might one have an amino acid substitution in a protein that does not result in an altered phenotype?

missence mutation that produces an amino acid that is similar chemically and structurally that does not affect the phenotype

what is a test cross used for?

to determine the genotype of an individual that expressed a dominant trait

DNA P III adds nucleotides

to the 3' end of the RNA primer

T/F: different Hfr strains have F factor integrated at different sites

true

T/F: tautomeric forms are unstable and will switch back to the more stable normal form of the base

true

T/F: two chains are antiparallel in the model of DNA structure

true

T/F: two long polynucleotide chains coiled around a central axis, forming a right-handed double helix for the model of DNA structure

true

T/F: xeroderma pigmentosum is autosomal recessive that has a predisposition to skin cancer and shows a deficiency in NER proteins

true

In the mouse, gene A allows pigmentation to be deposited in the individual coat hairs, while its allele a prevents such deposition of pigment, resulting in an albino. Gene B gives agouti (wild-type fur), while its allele b gives black fur. (a) Diagram the cross between a doubly heterozygous agouti mouse mated with a doubly homozygous recessive white mouse. (b) What would be the expected phenotypic ratio in the progeny?

(a) AaBb X aabb (b) 1 (agouti): 1 (black): 2 (albino)

A cross was made between homozygous wild-type female Drosophila and yellow-bodied male Drosophila. All of the resulting offspring were phenotypically wild-type. Offspring of the F2 generation had the following phenotypes: Sex Phenotype Number male wild 96 male yellow 99 female wild 197 Based on this information: (a) Is the mutant gene for yellow body behaving as a recessive or a dominant? (b) Is the yellow locus on an autosome or on the X chromosome?

(a) recessive (b) X-linked

In peas, gray seed color is dominant to white. For the purposes of this question, assume that Mendel crossed plants with gray seeds with each other and the following progeny were produced: 320 gray and 80 white. (a) What is the most probable genotype of each parent? (b) What genotypic and phenotypic ratios are expected in the progeny of such a cross?

(a) using the symbols G = gray and g = white, Gg X Gg (b) genotypic = 1:2:1, phenotypic = 3:1

what are the five exceptions to mendel's rules?

- codominance - multiple alleles - phenotypic expression - disease onset affecting inheritance - extranuclear inheritance

what are the two types of cells involved in conjugation in bacteria?

- donor cells (F+) - recipient cells (F-)

why is bacteria often used as a model organism for genetic mapping?

- fast growing - cheap - easy to obtain large number of offspring

what are the three criteria for three-point mapping cross?

- female is heterozygous for all 3 alleles in F1 - phenotype must be observable in the F2 generation - large number of progeny

what are the three keys to determining gene order for three-point genetic mapping?

- take one of the three options and determine the order of genes for single crossover events - see if a double crossover event will give rise to any of the observed phenotypes - if this does not work, try one of the other 2 gene orders

what are the criteria for genetic mapping?

- the most frequently occuring phenotype is the result of noncrossover events (how you determine the correct heterozygous arrangement of the alleles, NOT THE ORDER OF THE GENES) - the double crossovers will be the least frequent event (use this to determine the sequence of the genes) - determine the distance between each allele using the percentage from the single crossovers and the double crossovers

what are two disadvantages for using bacteria for genetic mapping?

- too numerous - difficulty in the characterization of phenotypes

Fill in the blanks in the "level of transcription" column of this table with: + for high levels of transcription, and - for minimal levels of transcription of the lac operon. Consider regulation by both the lac repressor and CAP (catabolite activator protein). The strain is wild type, with no partial diploidy. Please label your answer with numbers 1-4 based on the chart below. Medium conditions Level of transcription 1 high glucose, no lactose 2 no glucose, high lactose 3 high glucose, high lactose 4 no glucose, no lactose

-, +, -, -

what are the genetic materials of eukaryotic cells?

-DNA found in the nucleus, mitochondria, and chloroplasts -haploid vs. diploid chromosome context -mutagenesis

Bombay Phenotype

-Homozygous recessive condition at one locus that masks expression at a second locus hh masks the expression of the IA and IB alleles -Must have at least one wt H allele in order to express the A and B antigens -If a persons genotype includes the IA and IB alleles, but they are hh, then they will express the type O phenotype.

Codominance

-Where two alleles of a single gene produce two fully functional but distinct products. This is in contrast to Mendel's hypothesis in regard to the relationship between two alleles. Blood Types.

what are things that can induce a mutation?

-alternative chemical forms of the purines and pyrimidines -base analogs -alkylating agents -acridine dyes -apurinic/apyrimidinic sites -deamination -UV light and high energy radiation -oxidative damage-reactive oxidants -transposons

what are characteristics of yeast origins?

-contain repeating 11 bp sequences -serve as binding site for proteins that form the origin recognition complex (ORC) -DNA polymerase holoenzyme recognizes the ORC

what are the 5 components of a bacteriophage structure?

-head packed with DNA (~150 genes) -collar -tube sheath -tail -tail fibers -base plate

19:9

A microarray is a solid support containing an orderly arrangement of DNA samples. A typical array contains thousands of DNA spots that may be small oligonucleotides, cDNAs, or short genomic sequences. Labeled sequences hybridize to the immobilized DNAs by standard base pairing. Such technology allows a method for monitoring RNA expression levels of thousands of genes in virtually any cell population. Using microarray technology, researchers can observe the overall behavior of the genome in cancer and normal cells and, by comparison, determine which genes are active or inactive under various circumstances. It is possible to identify the set of genes whose expression or lack thereof defines the properties of each tumor type. This application can, therefore, lead to precise diagnosis and refine possible therapies. In addition, microarray profiling can be used to determine the efficacy of particular therapies. For instance, one can monitor responses to radiation and/or chemotherapy to determine the degree to which cells are responding to a particular cancer treatment.

Which of the following conditions are essential for the success of Gregor Mendel's genetics experiments? A. He picked a good model organism to work with B. He quantified his observations C. He did his work in isolation D. He made testable hypotheses E. He was supported by wealthy patrons

A, B, D

In E. coli, which terms accurately reflect the nature of replication of the chromosome? A. bidirectional and fixed point of initiation B. unidirectional and reciprocal C. unidirectional and fixed point of initiation D. multirepliconic E. bidirectional and multirepliconic

A. Bidirectional and fixed point of initiaiton

Which of the following are true during F+ x F- mating events? A. DNA is transferred from F+ to F- cells B. DNA is transferred from Fto F+ cells C. No DNA is transferred because F- cells are unable to perform conjugation D. No pilus is formed.

A. DNA is transferred from F+ to F- cells.

Name the individual whose work in the mid-1800s contributed to our understanding of the particulate nature of inheritance as well as the basic genetic transmission patterns. With what organism did this person work? A. Gregor Mendel, Pisum sativum B. George Beadle, Neurospora C. Thomas Hunt Morgan, Drosophila (fruit fly) D. Calvin Bridges, Drosophila (fruit fly) E. Boris Ephrussi, Ephestia

A. Gregor Mendel, possum sativum

A situation in which there are more than two alternative forms of a given gene is called ________. A. multiple alleles B. alternation of generations C. codominance D. incomplete dominance E. hemizygosity

A. Multiple alleles

The classic Hershey and Chase (1952) experiment that offered evidence in support of DNA being the genetic material in bacteriophages made use of the following labeled components: A. phosphorus and sulfur. B. nitrogen and oxygen. C. tritium. D. hydrogen. E. none of the above

A. Phosphorus and sulfur

What are three general mechanisms that appear to result in the conversion of proto-oncogenes to oncogenes? A. point mutations, translocations, overexpression B. inversions, translocations, methylation C. familial, sporadic, phosphorylation D. transdetermination, mutation, allosteric interactions E. suppression, tabulation, projection

A. Point mutations, transloations, overexpression

The fundamental Mendelian process that involves the separation of contrasting genetic elements at the same locus is called A. segregation. B. independent assortment. C. continuous variation. D. discontinuous variation. E. dominance or recessiveness.

A. Segregation

Nutritional mutations can be defined as A. those mutations that do not allow an organism to grow on minimal medium, but do allow the organism to grow on complete medium. B. those mutations that change the composition of the medium. C. those belonging to the group called prototrophs. D. those mutations caused by site-specific mutagenesis. E. all strains that are not auxotrophic.

A. Those mutations that do not allow an organism to grow on minimal medium, but do

Restriction endonucleases are especially useful if they generate "sticky" ends. What makes an end sticky? A. single-stranded complementary tails B. blunt ends C. poly-A sequences D. 5' cap E. interference

A. single stranded complementary tails

A. single-stranded complementary tails

What is a concise definition of proteomics? A. the process of defining the complete set of proteins encoded by a genome B. the harvesting of proteins from a cell to determine their economic value C. the manipulation of amino acid sequences in proteins to alter their function D. changing the terminal sequences of proteins to alter their function E. the rational design of drugs based on protein structure

A. the process of defining the complete set of proteins encoded by a genome

A. those mutations that do not allow an organism to grow on minimal medium, but do allow the organism to grow on complete medium.

DNA polymerase III adds nucleotides A. to the 3' end of the RNA primer. B. to the 5' end of the RNA primer. C. in the place of the primer RNA after it is removed. D. to both ends of the RNA primer. E. to internal sites in the DNA template.

A. to the 3' end of the RNA primer

A. to the 3' end of the RNA primer.

What general or global genetic process is believed to account for the variety of cellular structures and functions in eukaryotic cells? A. variable gene activity B. negative control exclusively C. maternal environmental activities D. intron processing E. RNA processing

A. variable gene activity

Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are genetically incapable of repairing some dimers at "normal" rates. Such individuals are likely to suffer from A. xeroderma pigmentosum. B. SCID. C. phenylketonuria. D. muscular dystrophy. E. Huntington disease.

A. xeroderma pigmentosum

A. xeroderma pigmentosum.

what is an example that professor chen used for multiple alleles?

ABO blood type (phenotype would be the antigens, blood type A has A antigens)

What is the initiator triplet in both prokaryotes and eukaryotes? What amino acid is recruited by this triplet?

AUG; methionine

The enzyme glucose-6-phosphate dehydrogenase deficiency (G6PD) is inherited as a recessive gene on the X chromosome in humans. A phenotypically normal woman (whose father had G6PD) is married to a normal man. (a) What fraction of their sons would be expected to have G6PD? (b) If the husband had G6PD, would it make a difference to your answer in part (a)?

Answer: (a) ½ (b) no

(a) Assume that A + T/G + C equals 0.5 in one strand of DNA. What is the ratio of these bases in the complementary strand? (b) If A + G/T + C equals 0.5 in one strand, what is the ratio of these bases in the complementary strand?

Answer: (a) 0.5 (b) 2.0

Two forms of hemophilia are determined by genes on the X chromosome in humans. Assume that a phenotypically normal woman whose father had hemophilia is married to a normal man. What is the probability that their first son will have hemophilia?

Answer: 1/2

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. What is the probability that their next child will be an albino girl?

Answer: 1/4 X 1/2 = 1/8

Assume that a dihybrid cross (AaBb X AaBb) is made in which the gene loci are autosomal, independently assorting, and incompletely dominant. What phenotypic ratio would you expect from such a cross? Provide just the ratio, not the phenotypes.

Answer: 1:2:1:2:4:2:1:2:1

A particular cross gives a modified dihybrid ratio of 9:7. What phenotypic ratio would you expect in a testcross of the fully heterozygous F1 crossed with the fully recessive type? Diagram the testcross using A,a,B,b as symbol sets.

Answer: 1:3 AaBb X aabb > AaBb, Aabb, aaBb, aabb

At what approximate wavelengths do DNA, RNA, and proteins maximally absorb light?

Answer: 260 nm, 260 nm, and 280 nm, respectively

The following F2 results occur from a typical dihybrid cross: purple: A_B_ 9/16 white: aaB_ 3/16 white: A_bb 3/16 white: aabb 1/16 If a double heterozygote (AaBb) is crossed with a fully recessive organism (aabb), what phenotypic ratio is expected in the offspring?

Answer: 3 (white):1 (purple)

What structural circumstance in DNA sets up the requirement for its semidiscontinuous nature of replication?

Answer: 5' > 3' polarity restrictions of DNA synthesis and the antiparallel orientation of the DNA strands in DNA

Describe the mutagenic action of any two of the following mutagens: 5-bromouracil, proflavin, ultraviolet light.

Answer: 5-bromouracil is an analogue of thymine, which anomalously pairs with guanine and can result in a substitution. Proflavin adds or removes single bases from DNA, thus causing frameshift mutations. Ultraviolet light causes thymine dimers that may slow or arrest DNA replication.

Describe the mutagenic action of the following mutagens: 5-bromouracil, ultraviolet light.

Answer: 5-bromouracil is an analogue of thymine, which anomalously pairs with guanine and can result in a substitution. Ultraviolet light causes thymine dimers that may slow or arrest DNA replication.

Assume that a given plasmid vector to be used in a cloning experiment contains 4000 base pairs of DNA. Assume also that the restriction endonuclease Cuj cuts this plasmid at the following sites (starting from an arbitrary zero point): 1000, 1500, and 3000. Given complete digestion of the plasmid with the endonuclease so that only linear fragments are produced, what sizes of DNA fragments are expected?

Answer: 500 bp, 1500 bp, and 2000 bp

Assume that one counted 67 plaques on a bacterial plate where 0.1 ml of a 10-5 dilution of phage was added to bacterial culture. What is the initial concentration of the undiluted phage?

Answer: 67 X 105 X 10 = 6.7 X 107 pfu/ml (pfu = plaque-forming units)

What types of ratios are likely to occur in crosses (F2) when one is dealing with two interacting, epistatic gene pairs?

Answer: 9:7, 9:3:4, 12:3:1, 15:1

What is a merozygote?

Answer: A merozygote is a partially diploid cell that results when, through recombination, a portion of a donor chromosome is introduced into a bacterium.

What is a tumor suppressor gene? What are oncogenes? What is the normal (nonmutant) cellular version of an oncogene called?

Answer: A tumor suppressor gene is a gene whose normal function is to suppress cell division. When mutant, cell division control is lost and a cancer may form. Oncogenes are genes that induce or maintain uncontrolled cellular proliferation associated with cancer. The normal cellular version of an oncogene is called a proto-oncogene.

Answer: A. The process of defining the complete set of proteins encoded by a genome

Three human disorders—fragile-X syndrome, myotonic dystrophy, and Huntington disease— are conceptually linked by a common mode of molecular upset. Describe the phenomena that link these disorders.

Answer: All three are caused by disparate genes, but each gene was found to contain repeats of a unique trinucleotide sequence. In addition, the number of repeats may increase in each subsequent generation (genetic anticipation).

What is an allele-specific oligonucleotide?

Answer: An allele-specific oligonucleotide is a stretch of DNA capable of either base pairing with a specific allele or failing to do so. Either way, such oligonucleotides can be used, under stringent hybridization conditions, to detect minor differences in DNA sequences.

Describe the difference between a proto-oncogene and an oncogene.

Answer: An oncogene is a mutant form of a proto-oncogene.

How does an auxotroph differ from a prototroph?

Answer: Auxotrophs have lost, through mutation, the ability to grow on minimal medium.

What are minisatellites and microsatellites?

Answer: Both are highly repetitive, relatively short DNA sequences. Microsatellites have a shorter repeat length than do minisatellites.

During the polymerization of nucleic acids, covalent bonds are formed between neighboring nucleotides. Which carbons are involved in such bonds?

Answer: C-3' and C-5'

Jacob, Wollman, and others developed a linkage map of E. coli that is based on time. What form of recombination is involved in generating a linkage map based on time?

Answer: Conjugation: An Hfr bacterium conjugating with an F- strain allows one to generate a map that is dependent on the passage of the donor chromosome across a conjugation tube.

What is meant by the term cotransformation?

Answer: Cotransformation occurs when several linked genes are transformed simultaneously.

List at least four enzymes known to be involved in the replication of DNA in bacteria.

Answer: DNA polymerase I, III, ligase, RNA primase, helicase, gyrase

Distinguish between F+ and F- bacteria.

Answer: F+ bacteria contain an F factor or plasmid that is capable of initiating conjugation.

"Loss-of-function" mutations are the same as the neutral mutations.

Answer: False

A missense mutation causes premature chain (protein) termination.

Answer: False

A nucleosome is a structure associated with the nuclear membrane. It helps maintain a stable relationship between the extracellular matrix and the membrane itself.

Answer: False

Acridine orange is an alkylating agent.

Answer: False

Avery et al. (1944) determined that DNA is the genetic material in bacteriophage.

Answer: False

Bacterial genes have introns, and eukaryotic genes lack introns.

Answer: False

DNA replicates conservatively, which means that one of the two daughter double helices is "old" and the other is "new."

Answer: False

Each human contains an identical set of VNTR

Answer: False

Each human contains an identical set of VNTRs.

Answer: False

Hershey and Chase used labeled DNA and protein to determine that DNA is the genetic material in bacteria.

Answer: False

Histones bind DNA through covalent bonds.

Answer: False

In 1953, Watson and Crick used X-ray crystallography to solve the structure of DNA.

Answer: False

In a bacterial cross where the donor (Hfr) is a+b+ and the recipient strain (F-) is a-b-, it is expected that recombinant bacteria will all be a+b+.

Answer: False

In a typical PCR, primers are used to cleave specific regions of the DNA template.

Answer: False

In contrast with euchromatin, heterochromatin contains more genes and is earlier replicating.

Answer: False

In humans, no genes are larger than 2 kb.

Answer: False

In the Meselson and Stahl (1958) experiment, bean plants (Vicia faba) were radioactively labeled so that autoradiographs could be made of chromosomes.

Answer: False

Introns are found only in prokaryotic genomes.

Answer: False

Lysogeny is a process that occurs during transformation and conjugation.

Answer: False

Multigene superfamilies are characterized by clusters of tandemly arranged unique pseudogenes organized as operons.

Answer: False

Reverse transcriptase is often used as the heat-stable enzyme in PCR.

Answer: False

The Human Genome Project seeks to rid the human population of genetic disease.

Answer: False

The gene p53 is called the "guardian of the genome" because it corrects mutations in the spindle apparatus before nondisjunction can occur.

Answer: False

The genome of humans is remarkably stable, so much so that there are no cancers known to result from genomic instability (the tendency for chromosomal aberrations to occur).

Answer: False

The genomic organization of all living creatures is identical.

Answer: False

The terms proteomics and genomics mean essentially the same thing

Answer: False

The transforming principle discovered by Griffith is RNA.

Answer: False

There are several checkpoints in the mitotic cell cycle. All occur in the S phase.

Answer: False

When referring to tumor suppressor genes and cancer, loss of heterozygosity is likely to suppress cancer formation.

Answer: False

Histones bind DNA through covalent bonds.

Answer: False -they are bound by hydrogen bonds

If the GC content of a DNA molecule is 60 percent, what are the molar percentages of the four bases (G, C, T, A)?

Answer: G = 30 percent, C = 30 percent, A = 20 percent, T = 20 percent

List the components of a nucleosome.

Answer: Histones H2A, H2B, H3, and H4 exist as two types of tetramers: (H2A)2 + (H2B)2 and (H3)2 + (H4)2. Together, these form an octamer. Histone H1 lies outside the octamer.

What is unusual about the amino acid composition of histones? How is the function of histones related to the amino acid composition? Of which histones are nucleosomes composed?

Answer: Histones contain large amounts of positively charged amino acids such as lysine and arginine. Thus, they can bind electrostatically to the negatively charged phosphate groups of nucleotides. Nucleosomes are composed of all histones except H1.

What is p53 and what is its significance?

Answer: It is a tumor suppressor gene that normally functions to control cell cycle transition including from late G1 to S and G2 to M. Mutations in the p53 gene are important in the development of a number of cancers. The product of p53 has DNA-binding properties.

What is the relationship between the degree of crossing over and the distance between two genes?

Answer: It is direct: as the distance increases, the frequency of recombination increases.

What are the commonly used sources of variation applied to human DNA profiling?

Answer: Often variations in DNA can be revealed by restriction endonucleases to generate restriction fragment-length polymorphisms (RFLPs). In addition, VNTRs, SNPs, and STRs provide individual variation suitable for DNA profiling.

A particular variant of the lambda bacteriophage has a double-stranded DNA genome of 51,365 base pairs. How long, in units of length measurement, would this DNA be?

Answer: One base pair is 0.34 nm; therefore, 51,365 bp X 0.34 nm/bp = 17,464 nm or 17.46 micrometers

A particular variant of the lambda bacteriophage has a double-stranded DNA genome of 51,365 base pairs. How long, in units of length measurement, would this DNA be?

Answer: One base pair is 0.34 nm; therefore, 51,365 bp X 0.34 nm/bp = 17,464 nm or 17.46 μm.

What is meant by the term photoreactivation repair?

Answer: Photoreactivation repair, discovered in 1949, is a process described in E. coli in which UV-induced DNA damage, specifically pyrimidine dimers, can be partially reversed if cells are briefly exposed to light in the blue range of the visible spectrum.

How are polytene chromosomes formed?

Answer: Polytene chromosomes are formed by parallel pairing of many homologous chromosomes after rounds of cell division.

Describe two classes of proteins known to be involved in the regulation of the cell cycle.

Answer: Protein kinases selectively phosphorylate target proteins. When complexed with cyclins, critical points of the cell cycle are controlled.

During DNA replication, what is the function of RNA primase?

Answer: RNA primase provides a free 3'-OH upon which DNA polymerization depends.

Describe the method of replication of mtDNA

Answer: The circular, double-stranded duplex is replicated semiconservatively.

Describe the method of replication of mtDNA.

Answer: The circular, double-stranded duplex is replicated semiconservatively.

Intron frequency varies considerably among eukaryotes. Provide a general comparison of intron frequencies in yeast and humans. What about intron size?

Answer: The entire yeast genome has only about 240 introns, whereas some single genes in humans contain over 100 introns. In general, smaller genomes have smaller intron size in addition to lower intron number.

DNA replication in vivo requires a primer with a free 3' end. What molecular species provides this 3' end, and how is it provided?

Answer: The free 3' end is provided by an RNA primer, which is provided by the enzymatic activity of RNA primase.

What two factors contribute significantly to the wide ranges of genome size among eukaryotes?

Answer: The presence of introns and repetitive sequences is a major contributor, as are the differences in the number of genes.

Describe the cellular and molecular function of the ras gene family and the consequences of mutations in ras.

Answer: The ras gene family encodes a protein of 189 amino acids, which is involved with signal transduction in the cell membrane. Point mutations may cause changes in function that promote abnormal signaling, thus stimulating uncontrolled cell growth.

What are the roles of the recBCD genes?

Answer: They function in bacterial recombination.

Describe three separate genetic mechanisms whereby proto-oncogenes can become overexpressed.

Answer: They may acquire a new promoter or upstream regulatory signals, additional copies (amplification), or a change to more transcription active chromatin structure.

"Gain-of-function" mutations are generally dominant since one copy in a diploid organism is sufficient to alter the normal phenotype.

Answer: True

A characteristic of aging cells is that their telomeres become shorter.

Answer: True

A restriction map provides the location of sites cleaved by restriction enzymes.

Answer: True

A retrovirus uses reverse transcriptase to make a DNA copy of RNA.

Answer: True

A typical epistatic ratio is 9:3:4.

Answer: True

An Hfr cell can initiate chromosome transfer from one E. coli to another.

Answer: True

Assume that a mutation occurs in the gene responsible for the production of hexosaminidase A, such that only about 50% of the enzyme activity is found in the heterozygote compared with a homozygous normal individual. If heterozygotes are phenotypically normal, we would say that the mutant allele is recessive to its normal allele.

Answer: True

Assuming complete dominance, a 3:1 phenotypic ratio is expected from a monohybrid sib or self-cross.

Answer: True

Cotransduction of genes is an indication that the genes are linked.

Answer: True

DNA strand replication begins with an RNA primer

Answer: True

DNA strand replication begins with an RNA primer.

Answer: True

G and C are present in both DNA and RNA.

Answer: True

Glyphosate (a herbicide) inhibits EPSP, a chloroplast enzyme involved in the synthesis of several amino acids.

Answer: True

RNAi (RNA interference) is a form of gene expression regulation in which double-stranded RNA molecules act, through various intermediates, to degrade mRNAs.

Answer: True

Strand discrimination during the process of DNA repair is based on DNA methylation in E. coli.

Answer: True

Telomerase is an RNA-containing enzyme that adds telomeric DNA sequences onto the ends of linear chromosomes.

Answer: True

The E. coli chromosome is circular, double-stranded DNA.

Answer: True

The cross GE/ge X ge/ge produces the following progeny: GE/ge 404; ge/ge 396; gE/ge 97; Ge/ge 103. From these data one can conclude that the recombinant progeny are gE/ge and Ge/ge.

Answer: True

The shorter the wavelength of a radiation source, the greater its likelihood of causing damage.

Answer: True

To generate glyphosate resistance in crop plants, a fusion gene was created that introduced a viral promoter to control the EPSP synthetase gene.

Answer: True

To test Mendel's law of independent assortment, the experimenter needs a minimum of two different genes and their two alleles.

Answer: True

To test Mendel's law of segregation, the experimenter needs a minimum of two contrasting forms of a gene.

Answer: True

Typically, bacterial DNA contains less repetitive DNA than eukaryotic DNA.

Answer: True

What is the difference between tumor suppressor genes and proto-oncogenes?

Answer: Tumor suppressor genes act to restrict cell division, while proto-oncogenes act to stimulate cell division.

DNA fingerprinting often makes use of VNTRs. Why?

Answer: VNTRs (variable number tandem repeats) are highly variable portions of eukaryotic chromosomes. They are sufficiently variable as to be unique to each individual.

To what scientific activities do the terms synkaryon and heterokaryon refer?

Answer: cell (heterokaryon) and nuclear (synkaryon) fusion and gene mapping in eukaryotes

What primary ingredients, coupled with DNA polymerase I, are needed for the in vitro synthesis of DNA?

Answer: dNTP, DNA template, primer DNA or RNA,

What primary ingredients, coupled with DNA polymerase I, are needed for the in vitro synthesis of DNA?

Answer: dNTP, DNA template, primer DNA or RNA, Mg2+ (appropriate buffering, temperature, and salt concentrations might be considered "secondary" ingredients)

In the polymerase chain reaction, what is the purpose of the initial high temperature? What is the purpose of cooling in the second step?

Answer: denature the target (template) DNA; annealing of the primer to the target

Discuss the possible origin of mitochondria and chloroplasts.

Answer: development of endosymbionic relationships between primitive, free-living bacteria-like organisms

The white-eye gene in Drosophila is recessive and sex-linked. Assume that a white-eyed female is mated to a wild-type male. What would be the phenotypes of the offspring?

Answer: females wild-type, males white-eyed

What is the common influence of ultraviolet light on DNA?

Answer: generation of pyrimidine dimers

What enzyme is responsible for the initial step in unwinding the DNA helix during replication of the bacterial chromosome?

Answer: helicase

In general, what two methods are used to grow bacteria in the laboratory?

Answer: liquid and semisolid (agar) media

The genes for mahogany eyes and ebony body are approximately 25 map units apart on chromosome III in Drosophila. Assume that a mahogany-eyed female was mated to an ebony-bodied male and that the resulting F1 phenotypically wild-type females were mated to mahogany, ebony males. Of 1000 offspring, what would be the expected phenotypes, and in what numbers would they be expected?

Answer: mahogany = 375; ebony = 375; wild-type = 125; mahogany-ebony = 125.

List three general categories of genetic changes that lead to the formation of oncogenes.

Answer: point mutations, translocations, overexpression

What is the expected evolutionary significance of genetic recombination?

Answer: production of genetic variation

Name the pyrimidines and the purines in DNA.

Answer: pyrimidines: cytosine and thymine; purines: adenine and guanine

List two major differences between RNA and DNA at the level of the nucleotide.

Answer: ribose in RNA, deoxyribose in DNA; uracil in RNA replaces thymine in DNA

In Drosophila, assume that the gene for scute bristles (s) is located at map position 0.0 and that the gene for ruby eyes (r) is at position 15.0. Both genes are located on the X chromosome and are recessive to their wild-type alleles. A cross is made between scute-bristled females and ruby-eyed males. Phenotypically wild-type F1 females were then mated to homozygous double mutant males, and 1000 offspring were produced. Give the phenotypes and frequencies expected.

Answer: scute = 425; ruby = 425; wild-type = 75; scute-ruby = 75

What is the specific application of reverse transcriptase in the preparation of cDNA?

Answer: synthesis of DNA from a single-stranded RNA template to form an RNA-DNA duplex

One type of mutation involves the replacement of a purine with a purine, while another causes the replacement of a pyrimidine with a purine. What general terms are associated with these two mutational phenomena?

Answer: transition and transversion, respectively

What is the name of the precursor molecule used in nucleic acid synthesis?

Answer: triphosphonucleoside

Answer: (a) 0.5 (b) 2.0

List at least two different types of DNA repair and briefly explain how each is carried out.

Any three of the following - 1. Mismatch repair. Replication errors that are the result of base-pair mismatches are repaired. Mismatch repair enzymes recognize distortions in the DNA structure due to mispairing and detect the newly synthesized strand by the lack of methylation on the new strand. The bulge is excised and DNA polymerase and DNA ligase fill in the gap. 2. Direct repair. DNA damage is repaired by directly changing the damaged nucleotide back to its original structure. 3. Base excision repair. The damaged base is excised, and then the entire nucleotide is replaced. 4. Photo reactive repair - reversal of pyrimidine dimers formed by uv light exposure. Requires the photoactivation enzyme 5. Post-replication repair - occurs on damaged DNA that has escaped initial mismatch repair during DNA replication. In this mechanism the RecA protein recombines the corresponding on the undamaged parental strand of the same polarity 6. Double strand break repair - responsible for attaching two broken strands of DNA - uses homologous recombination repair and the corresponding region on the sister chromatid as a template 7. Nucleotide Excision Repair (NER) - able to remove wide range of defects in DNA especially bulky DNA lesions. Chunk of roughly 22-30 nucleotides is removed leaving a single stranded gap that is then filled in and sealed.

A bacterial operon A. contains information for one protein product. B. contains information for more than one protein product. C. is capped at the 5′ end and carries a poly-A tail at the 3′ end. D. is void of start (AUG) and termination (UAA, UGA, UAG) triplets. E. none of the above

B. Contains information for more than one protein product

It is common to use ddNTPs (dideoxyribonucleoside triphosphates) in which of the following biochemical reactions? A. citric acid cycle B. DNA sequencing C. restriction digestion D. electron transport E. plasmolysis

B. DNA sequencing

A condition in which one gene pair masks the expression of a nonallelic gene pair is called ________. A. codominance B. epistasis C. dominance D. recessiveness E. additive alleles

B. Epistasis

A bacterial operon A. contains information for one protein product B. contains information for more than one protein product C. is capped at the 5′ end and carries a poly-A tail at the 3′ end D. is void of start (AUG) and termination (UAA, UGA, UAG) triplets E. none of the above

B. contains information for more than one protein product

Lysogenic

Bacteriophage infects the cell, but the phage DNA integrates into the host cell genome.

Lytic

Bacteriophage infects the cell, replicates, and lyses the cell.

What might Watson and Crick have concluded, had Chargaff's data from a single source indicated the following base composition? A T G C % 29 19 21 31 Why would this conclusion be contradictory to Wilkins and Franklin's data?

Because in double-stranded DNA, A = T and G = C (within limits of experimental error), the data presented would have indicated a lack of pairing of these bases in favor of a single-stranded structure or some other nonhydrogen-bonded structure. Alternatively, from the data it would appear that A = C and T = G, which would negate the chance for typical hydrogen bonding since opposite charge relationships do not exist. Therefore, it is quite unlikely that a tight helical structure would form at all.

Name two forms of recombination in bacteria. A. lytic and lysogenic B. auxotrophic and prototrophic C. conjugation and transduction D. mixed and generalized E. insertion and replication

C. Conjugation and transduction

Viral chromosomes exist in a variety of structures and can be made up of the following: A. protein or lipid coding sequences. B. DNA only. C. DNA or RNA. D. RNA only. E. DNA, RNA, or protein.

C. DNA or RNA

One of the primary reasons for the necessity of generating a large number of clones in a eukaryotic genomic library is that A. each cosmid replicates nonautomously. B. lysogenic phages continue to integrate their DNA into the host chromosome, thus reducing the number of desired recombinant clones. C. each vector can take up only a very small fraction of the eukaryotic DNA. D. each ligation product is sequence-specific. E. the host range of the vector is limited.

C. Each vector can take up only a very small fraction of the eukaryotic DNA

Short tandem repeats (STRs) are very similar to VNTRs, but the motif is shorter (two to nine base pairs). The FBI and other law enforcement agencies couple PCR with STR analyses to A. increase the number of records for each suspect from two to nine. B. alter the genetic makeup of their agents. C. establish databases against which suspects can be screened. D. genetically type all individuals in any given country. E. calculate the probability that a given gene will exist in a given population.

C. Establish databases against which suspects can be screened

When two genes fail to assort independently, the term normally applied is ________. A. discontinuous inheritance B. Mendelian inheritance C. linkage D. tetrad analysis E. dominance and/or recessiveness

C. Linkage

Some vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region. What term is given to this advantageous arrangement of restriction sites? A. palindrome B. consensus sequence C. polylinker D. β-galactosidase E. complementation

C. Polylinker

Mutations that arise in nature, from no particular external agent, are called A. natural mutations. B. induced mutations. C. spontaneous mutations. D. chromosomal aberrations. E. cosmic mutations.

C. Spontaneous mutations

The discontinuous aspect of replication of DNA in vivo is caused by A. polymerase slippage. B. trinucleotide repeats. C. the 5' to 3' polarity restriction. D. topoisomerases cutting the DNA in a random fashion. E. sister-chromatid exchanges.

C. The 5' to 3' polarity restriction

In the classic experiment conducted by Hershey and Chase, why was the pellet radioactive in the centrifuge tube that contained bacteria with viruses, which had been grown on medium containing 32P? A. The bacteria were in the pellet, and they had incorporated radioactive proteins into their cell membranes. B. The radioactive viruses (coats plus DNA) were in the pellet. C. The bacteria were in the pellet, and many contained the radioactive viral DNA. D. The radioactive protein coats of the viruses were in the pellet. E. The radioactive viruses were in the pellet, and the bacteria were in the supernatant.

C. The bacteria were in the pellet, and many contained the radioactive viral DNA

C. The bacteria were in the pellet, and many contained the radioactive viral DNA.

When two proteins show a 50 to 70 percent match in amino acid sequence, it is likely that A. the two proteins have identical functions. B. the two proteins have no common origin. C. the two proteins share a common ancestry. D. the two proteins have identical tertiary structures. E. the primary structures may differ but the secondary structures are identical.

C. The two proteins share a common ancestry

Two formal terms used to describe categories of mutational nucleotide substitutions in DNA are A. base analogues and frameshift. B. error prone and spontaneous. C. transversions and transitions. D. euchromatic and heterochromatic. E. sense and antisense.

C. Transversions and transitions

VNTRs are sections of DNA with the following characteristics: A. variable amino acid substitutions, highly heterogeneous. B. variable numbers of tandem repeats, highly uniform in the population. C. variable numbers of tandem repeats, variable in the population. D. various nucleotides transcribed repeatedly, homogeneous. E. very noteworthy transcribed regions, lethal genes.

C. Variable number of tandem repeats, variable in the population

In human chromosomes, there are satellite DNA sequences of about 170 base pairs in length that are present in tandem arrays of up to 1 million base pairs. Found mainly in centromere regions, they are called A. telomeres. B. primers. C. alphoid families. D. euchromatic regions. E. telomere-associated sequences.

C. alphoid families

C. alphoid families.

What is the term that refers to the regulatory events that establish a specific pattern of gene activity and developmental fate for a given cell? A. lysogen B. differentiation C. determination D. gradient regulated E. attenuation

C. determination

One of the primary reasons for the necessity of generating a large number of clones in a eukaryotic genomic library is that A. each cosmid replicates nonautomously B. lysogenic phages continue to integrate their DNA into the host chromosome, thus reducing the number of desired recombinant clones C. each vector can take up only a very small fraction of the eukaryotic DNA D. each ligation product is sequence-specific E. the host range of the vector is limited

C. each vector can take up only a very small fraction of the eukaryotic DNA

Short tandem repeats (STRs) are very similar to VNTRs, but the motif is shorter (two to nine base pairs). The FBI and other law enforcement agencies couple PCR with STR analyses to A. increase the number of records for each suspect from two to nine B. alter the genetic makeup of their agents C. establish databases against which suspects can be screened D. genetically type all individuals in any given country E. calculate the probability that a given gene will exist in a given population

C. establish databases against which suspects can be screened

Assume that a cross is made between AaBb and aabb plants and that the offspring occur in the following numbers: 106 AaBb, 48 Aabb, 52 aaBb, 94 aabb. These results are consistent with the following circumstance: A. sex-linked inheritance with 30% crossing over. B. linkage with 50% crossing over. C. linkage with approximately 33 map units between the two gene loci. D. independent assortment. E. 100% recombination.

C. linkage with approximately 33 map units between the two gene loci

Mutant versions of genes that are normally involved in promoting the cell cycle are known as A. tumor suppressors B. proto-oncogenes C. oncogenes D. malignant genes E. attenuators

C. oncogenes

Words such as "Mom" "Dad" and "live evil" might have special significance when considering the fundamental tools of recombinant DNA technology. What term would be used to describe such words in the context of recombinant DNA technology? (See Problems and Discussion Questions for a description.) A. lysogenic B. prototrophic C. palindromic D. conjugation E. insertion

C. palindromic

C. polylinker

Mutations that arise in nature, from no particular external agent, are called A. natural mutations. B. induced mutations. C. spontaneous mutations. D. chromosomal aberrations. E. cosmic mutations.

C. spontaneous mutations.

When two proteins show a 50 to 70 percent match in amino acid sequence, it is likely that A. the two proteins have identical functions B. the two proteins have no common origin C. the two proteins share a common ancestry D. the two proteins have identical tertiary structures E. the primary structures may differ but the secondary structures are identical

C. the two proteins share a common ancestry

C. transversions and transitions.

Concerning sporadic cases (non-familial) of retinoblastoma, at least how many gene mutations are thought to be necessary in the same cell for a tumor to develop? A. one B. four C. two D. six E. insufficient information to answer this question

C. two

VNTRs are sections of DNA with the following characteristics: A. variable amino acid substitutions, highly heterogeneous B. variable numbers of tandem repeats, highly uniform in the population C. variable numbers of tandem repeats, variable in the population D. various nucleotides transcribed repeatedly, homogeneous E. very noteworthy transcribed regions, lethal genes

C. variable numbers of tandem repeats, variable in the population

Name two mutagens that are classified as base analogues. A. acridine orange and proflavin B. ethylmethane sulfonate and ethylmethylketone peroxide C. ultraviolet light and cosmic radiation D. 5-bromouracil and 2-aminopurine E. hydroxyurea and peroxidase

D. 5-bromouracil and 2-aminopurine

In Drosophila, segmentation genes function in a sequential manner in the following order: A. gap, segment polarity, pair rule B. pair rule, transdeterminal, gap C. transdeterminal, gap, pair rule D. gap, pair rule, segment polarity E. segmentational, helical, spherical

D. gap, pair rule, segment polarity

A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to be the following: A. base analogue. B. transversion. C. transition. D. insertion E. recombinant.

D. insertion

A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to be the following: A. base analogue. B. transversion. C. transition. D. insertion E. recombinant.

D. insertion

In general, the organization of genes in bacteria is different from that in eukaryotes. In E. coli, approximately 27 percent of all genes are organized into contiguous, functionally related units containing multiple genes under coordinate control that are transcribed as a single unit. Such contiguous gene families are called A. transcriptomes B. proteomes C. contigs D. operons E. pseudogenes

D. operons

What protein functions as a cell-cycle regulator by causing cell death (apoptosis) after the cell has been exposed to ultraviolet light or other forms of radiation? A. p34 B. p102 C. cyclin D. p53 E. phosphokinase

D. p53

in the lactose operon, the product of structural gene lacZ is capable of A. nonautonomous replication. B. forming lactose from two glucose molecules. C. replacing hexokinase in the early steps of glycolysis. D. splitting the B-linkage of lactose. E. forming ATP from pyruvate.

D. splitting the B-linkage of lactose.

the initiation of DNA synthesis: a complementary RNA primer is first synthesized, to which ______ is added all synthesis is in the ___ to ____ direction Eventually, the RNA primer is replaced with DNA under the direction of DNA Pol ____

DNA 5' to 3' 1 (I)

the conclusions from avery, mccarty, and macleod: ________ is the transforming principle the transforming principle from the heat-killed virulent cells interact with the live avirulent cells and results in __________ reactions that produces smooth polysaccharides on the avirulent cells they showed that once transformation occurs, it was __________, and therefore the process affects the genetic material

DNA enzymatic heritable

four enzymes known to be involved in the replication of DNA in bacteria

DNA P I, III, ligase, RNA primase, helicase, gyrase

list nuclear-encoded gene products that are essential to the biological activity of mitochondria

DNA and RNA polymerases, intitation and elongationg factors required for translation, ribosomal proteins, aminoacyl tRNA synthetases, and some RNAs

A protein containing a Zinc-finger domain is most likely a

DNA binding protein

what genetic material is this for eukaryotic cells? sites of primary genetic function and protein found throughout the cell

DNA found in the nucleus, mitochondria and chloroplasts

what is this describing? unwinding causes supercoiling downstream from the unwound region that must be relieved relieves supercoiling by cutting and then resealing the DNA

DNA gyrase

Through the Dutch Winter Studies, the scientists discovered a significantly increased obesity rate among the adults who were either born or conceived in Netherlands when the Nazi Germany cut off the food supplies to a large part of the country at the end of World War II. The genetics studies have mostly attributed this to ___ of the genome triggered by the environment.

DNA methylation

viral chromosomes exist in a variety of structures and can be made up of

DNA or RNA

what does the looping of lagging strand allow?

DNA pol to move in the same direction on both strands

______ __________ has a proofreading function that can repair misincorporated bases, reason for the high level of fidelity in replication, occasionally these bases will remain after proofreading, mismatch repair fixes these mistakes

DNA polymerase

what enzyme catalyzes DNA replication?

DNA polymerase

protein responsible for the initial step in unwinding the DNA helix during replication of the bacterial chromosome

DnaA

corn kernel development: corn with a wt gene for kernel color have colored kernels, a mutant gene produces colorless kernels (they are actually yellow) mutation is caused by insertion of _____ into the gene if ____ is also present it can cause reversions and induces ______ transpositon out of the gene any cells in which ____ has transposed out will produce pigment that results in spotting of the kernel the size of the spot is determined by when the reversion takes place during kernel development

Ds Ac Ds Ds

18:17

During mRNA processing, alternative splicing can produce many different mRNAs through combinations of the exons from one gene. This process in turn produces many different proteins from just one gene.

Chiasmata

During meiosis the synapsed chromosomes wrap around each other creating points of overlap

Assume that a circular plasmid is 3200 base pairs in length and has restriction sites at the following locations: 400, 700, 1400, 2600. Give the expected sizes of the restriction fragments following complete digestion. A. 400, 800, 1000 (two of these) B. 400, 1200, 1600 C. 300, 700, 2200 D. 700, 400, 1400, 2600 E. 300, 700, 1000, 1200

E. 300, 700, 1000, 1200 Hint: You can draw a circle and annotate all the restriction sites to calculate the expected DNA fragments after digestion.

Name the general category into which double-stranded circular extrachromosomal DNA elements such as F factors, ColE1, and R fall. A. capsid B. r-determinant C. plaque D. partial diploid E. plasmid

E. Plasmid

A DNA microarray (also called a DNA chip) can be used to A. mutate genes of interest. B. isolate genes from eukaryotic cell nuclei. C. assay protein output from a genomic database. D. trap genes that are both active and inactive. E. scan a population of nucleic acids for abundance and mutations.

E. Scan a population of nucleic acids for abundance and mutations

NER proteins were first isolated from __________ uvrA, uvrB, uvrC were all recognizing and clipping out lesions in DNA a specific number of nucleotides are always removed ____ in prokaryotes and ____ in eukaryotes repair is completed by DNA Pol _____ and ligase with the undamaged strand serving as the template

E. coli-uvr 13 28 1

A DNA microarray (also called a DNA chip) can be used to A. mutate genes of interest B. isolate genes from eukaryotic cell nuclei C. assay protein output from a genomic database D. trap genes that are both active and inactive E. scan a population of nucleic acids for abundance and mutations

E. scan a population of nucleic acids for abundance and mutations

Chloroplast DNA is usually linear.

False

During translation elongation, tRNA always enters the P-site of ribosome first.

False

Eukaryotes have only one RNA polymerase, like prokaryotes.

False

Genetic codes are universally conserved in all living organisms with no exception

False

In contrast with euchromatin, heterochromatin contains more genes and is earlier replicating.

False

In the presence of glucose in the media, CAP protein of E.coli binds to the DNA next to the promoter region of Lac operaon to inhibit the transcription of the structural genes.

False

Messenger RNA is usually polycistronic in eukaryotes.

False

Mitochondria DNA encodes all the genes required for the biological activity of mitochondria.

False

Regulation of RNA transport through the nuclear membrane is as common in prokaryotes as in eukaryotes.

False

Transcription in eukaryotes is generally influenced by enhancers, just as in prokaryotes.

False

True or false: A homeobox gene is one that produces a group of repetitive base sequences such as a VNTR.

False

True or false: Bacterial genes have introns, and eukaryotic genes lack introns.

False

True or false: In a typical PCR, primers are used to cleave specific regions of the DNA template.

False

True or false: In humans, no genes are larger than 2 kb.

False

True or false: Introns are found only in prokaryotic genomes.

False

True or false: Multigene superfamilies are characterized by clusters of tandemly arranged unique pseudogenes organized as operons.

False

True or false: Reverse transcriptase is often used as the heat-stable enzyme in PCR.

False

True or false: Segmentation genes, such as the pair-rule class, are inherited through mitochondrial DNA in Drosophila.

False

True or false: The Human Genome Project seeks to rid the human population of genetic disease.

False

True or false: The gene p53 is called the "guardian of the genome" because it corrects mutations in the spindle apparatus before nondisjunction can occur.

False

True or false: The genome of humans is remarkably stable, so much so that there are no cancers known to result from genomic instability (the tendency for chromosomal aberrations to occur).

False

True or false: The genomic organization of all living creatures is identical.

False

True or false: The terms proteomics and genomics mean essentially the same thing.

False

True or false: There are several checkpoints in the mitotic cell cycle. All occur in the S phase.

False

True or false: When referring to tumor suppressor genes and cancer, loss of heterozygosity is likely to suppress cancer formation.

False

Lampbrush chromosomes were abnormal DNA structures identified in human patients.

False.

Define gene regulation. What are three ways gene regulation can be controlled in a cell?

Gene regulation is defined as the control of a gene's transcript and its protein product. It can be achieved by altering either the transcription of the gene (RNA level), the translation of the protein from that transcript or by altering the structure of DNA such that transcription cannot occur.

Cotransduction

Genes that are closely linked on the bacterial chromosome can be simultaneously transduced.

Genotype

Genetic makeup of an organism.

in peas, gray seed color is dominant to white. for the purposes of this question, assume that Mendel crossed plants with gray seeds with each other and the following progeny were produced 320 gray and 80 white -what is the most probably genotype of each parent

Gg x Gg

Genetic Recombination in Bacteria

Process that leads to the formation of new gene combinations on chromosomes.

during DNA replication, what is the function of RNA primase

RNA primase provides a free 3'-OH upon which DNA polymerization depends

Define RNA silencing (or interference). Explain how siRNAs arise and how they potentially affect gene expression. How are siRNAs different from the antisense RNA mechanism?

RNA silencing, or RNA interference, occurs when double-stranded RNA molecules are cleaved and processed to produce small single-stranded interfering RNAs (siRNAs). These siRNAs bind to complementary sequences in mRNA molecules, stimulating cleavage and degradation of the mRNA. The siRNAs may also stimulate DNA methylation at DNA sequences complementary to the siRNAs. The paired mRNA-siRNA attracts a protein-RNA complex that cleaves the mRNA in an area bound by the siRNA. Following the initial cleavage, the mRNA is further degraded. The cleavage and subsequent degradation of the mRNA make it unavailable for translation. DNA methylation in the nucleus stimulated by siRNAs also affects transcription. Antisense RNA binds to mRNAs also, but physically interferes with translation

an intron is a section of

RNA that is removed during RNA processing

The sequence of a mRNA is 5'-AUGTTCTTGCCG-3'. During the translation initiation of this mRNA, which codon will occupy "A" site of the ribosome at first?

TTC

17:18

Taq polymerase is from a bacterium called Thermus aquaticus, which typically lives in hot springs. It is heat stable like some other enzymes used in PCR that are isolated from thermal vents in the ocean floor.

Describe the role of 15N in the Meselson-Stahl experiment.

The Meselson and Stahl experiment has the following components. By labeling the pool of nitrogenous bases of the DNA of E. coli with the heavy isotope 15N, it was possible to "follow" the "old" DNA. This was accomplished by growing the cells for many generations in medium containing 15N. Cells were transferred to 14N medium so that "new" DNA could be detected. A comparison of the density of DNA samples at various times in the experiment (initial 15N culture, and subsequent cultures grown in the 14N medium) showed that after one round of replication in the 14N medium, the DNA was half as dense (intermediate) as the DNA from bacteria grown only in the 15N medium. In a sample taken after two rounds of replication in the 14N medium, half of the DNA was of the intermediate density and the other half was as dense as DNA containing only 14N DNA.

True or false: Glyphosate (a herbicide) inhibits EPSP, a chloroplast enzyme involved in the synthesis of several amino acids.

True

what is this definition? loss of either thymine or cytosine AP sites occur spontaneously, happens many thousands of times daily if not repaired these sites can cause the Pol to stall and possibly insert the wrong base resulting in a mutation

apymimidinic site (AP site)

who was the founder of this experiment? performed "genetic transformation" studies on diplococcus pneumoniae, and concluded that "a deoxyribose nucleic acid is the fundamental unit of the transforming principle of pneumococcus type II"

avery, mccarty, and macleod (1944)

in the classic experiment conducted by Hershey and Chase, why was the pellet radioactive in the centrifuge tube that contained bacteria with viruses, which had been grown on medium containing 32p

bacteria were in the pellet, and many contained the radioactive viral DNA

what does BER stand for and what does it do?

base excision repair corrects minor chemical alterations of nitrogenous bases that were created by spontaneous hydrolysis of chemical agents they are minor errors and usually do not impair DNA replication or transcription

what effect of mutation trait is this? mating behavior, circadian rhythms

behavioral

In E. coli, which terms accurately reflect the nature of replication of the chromosome?

bidirectional and fixed point of initiation

during assembly of a bacteriophage the tail components are added to the head and then tail fibers are added during infection the tail fibers recognize ________ _________ on the surface of the bacterial cell wall

binding sites

what is the example professor chen gave us for epistasis?

bombay phenotype

does this define F factors or R plasmids? - small circular double-stranded DNA molecules - distinct from the genomic DNA

both

what type of mutation is this? changes in a whole or part of a chromosome

chromosomal

genetic recombination in bacteria is a process that leads to the new formation of new gene combinations on ___________ replace one or more genes present in a strain with genes from a genetically ________ strain produces an altered __________

chromosomes distinct phenotype

in e coli, the genetic material is composed of

circular, double-stranded DNA

describe method of replication of mtDNA

circular, double-stranded duplex is replicated semiconservately

Which of the following clusters of terms applies when addressing enhancers as elements associated with eukaryotic genetic regulation?

cis-acting, variable orientation, variable position

probability of a double crossover is much lower than probability of a single crossover for genes that are ______ together, the probability of a double crossover will be even ______

close less

ratio of a complete linkage is usually only observed when genes are very ______ and number of progeny is _______

close small

what are polyribosomes

clusters of ribosomes simultaneously translating the same mRNA

what type of dominance is this? when two alleles of a single gene produce fully functional but distinct products

codominance

what is the name given to the three bases in a messenger RNA that bind to the anticodon of tRNA to specify an AA placement in a protein

codon

bacteria that are in a particular physiological state to become transformed are called

competent

Attenuation of the tryptophan operon by tryptophan-tRNA requires ____ of the leader sequence

complete translation

Describe the major cellular and molecular events that mark the entry of mitosis from G2.

condensation of chromatin to form chromosomes, breakdown of the nuclear membrane, alterations in the cytoskeleton, formation of an active CDK1/cyclin B complex

describe the major cellular and molecular events that mark the entry of mitosis from G2

condensation of chromatin to form chromosomes, breakdown of the nuclear membrane, alterations in the cytoskeleton, formation of an active CDK1/cyclin B complex

what are the three processes that can lead to recombination in bacteria?

conjugation transformation transduction

name two forms of recombination in bacteria

conjugation and transduction

name three forms of recombination in bacteria

conjugation, transformation and transduction

jacob, wollman and others developed a linkage map of E coli that is based on time. what form of recombination is involved in generating a linkage map based on time

conjugation. Hfr bacterium conjugating with an F- strain allows one to generate a map that is dependent on the passage of the donor chromosome across a conjugation tube

what mode of DNA replication is this? complementary polynucleotide chains are synthesized, two newly created strands come together and two parental strands reassociate

conservative

what are the three modes of DNA replication?

conservative semi-conservative dispersive

Mutations in the lacI and lacO genes in the lactose system often lead to full production of the three structural genes related to the lac operon even with no lactose available to the organism. Such mutations would be called ________

constitutive

mutations in the lacI and lacO genes of the lac regulatory system in e coli often lead to full transcription of the three structural genes, even who no lactose is available to the organism. such mutations are called

constitutive

17:19

ddNTPs are analogs of the "normal" deoxyribonucleotide triphosphates (dNTPs), but they lack a 3'-hydroxyl group. As DNA synthesis occurs, the DNA polymerase occasionally inserts a ddNTP into a growing DNA strand. Since there is no 3'-hydroxyl group, chain elongation cannot take place, and resulting fragments are formed that can be separated by electrophoresis. Where the ddNTP was incorporated, the length of each strand and therefore the position of the particular ddNTP are established and used to eventually provide the base sequence of the DNA.

Mutagenic studies of the promoter region of the β-globin gene indicate that some areas are more likely than mutations in other areas to affect transcription rates. When mutations occur in consensus sequences (modular elements such as GC box, CAAT box, TATA box), transcription will ___

decrease

in the PCR, what is the purpose of inital high temperature? what is the purpose of cooling in the second step?

denature the target (template) DNA, annealing the primer to the target

possible origin of mitochondria and chloroplasts

development of endosymbiotic relationships between primitive, free-living bacteria-like organisms

Under what conditions does one expect a 9:3:3:1 ratio?

dihybrid cross (F2) with independently assorting, completely dominant genes

under what conditions does one expect a 9:3:3:1 ratio

dihybrid cross (f2) with independently assorting, completely dominant genes

what are two joined nucleotides called?

dinucleotide

what is the relationship between the degree of crossing over and the distance between two genes

direct, as the distance increases, the frequency of recombination increases

what mode of DNA replication is this? parental strands are dispersed into two new double helices following replication, each strand consists of old and new, this mode would involve cleavage of parental strands during replication

dispersive

how do you calculate the distance for a three point mapping cross?

distance between the three loci = the percentage of crossovers between each loci (SCOs and DCOs)

Under certain conditions, the rate of mutation of a particular gene may be determined in humans. What properties of the mutation would favor the most direct determination of mutation rate in humans? Select all that apply. - recessive - dominant - fully expressed - 100% penetrant - single locus

dominant, fully expressed, 100% penetrant, single locus

what type of crossover is this? two separate, independent exchanges (x-overs) that occur simultaneously result in a double exchange of genetic material probability of a single exchange is directly related to the distance between two genes

double crossover

what DCOs stand for?

double crossovers

what is this definition? the transmission of genes that occur outside the nucleus (non-mendelian inheritance)

extranuclear inheritance

what do centromeres do?

facilitate segregation of chromosomes to daughter nuclei

regarding the nature of ABO blood groups, what condition leads to the O blood type

failure to modify the H substance due to lack of glysoyltransferase activity

(T/F) A nucleosome is a structure associated with the nuclear membrane. It helps maintain a stable relationship between the extracellular matrix and the membrane itself.

false

Prokaryotic and eukaryotic ribosomes are structurally and chemically identical.

false

T/F The gene p53 is called the "guardian of the genome" because it corrects mutations in the spindle apparatus before nondisjunction can occur.

false

T/F: When referring to tumor-suppressor genes and cancer, loss of heterozygosity is likely to suppress cancer formation.

false

t/f DNA replicates conservatively, which means that one of the two daughter double helices is 'old' and the other is 'new'

false

t/f a 3'-polyA tail and 5' cap are common components of prokaryotic RNAs

false

t/f human genome project seeks to rid the human population of genetic disease

false

t/f in a bacterial cross where the donor (Hfr) is a+b+ and the recipient strain (F-) is a-b-, it is expected that recombinant bacteria will all be a+b+

false

t/f in contrast with euchromatin, heterochromatin contains more genes and is earlier replicating

false

t/f in the meselson and stahl experiment, bean plants were radioactively labeled so that autoradiographs could be made of chromosomes

false

t/f introns are found only in prokaryotic genomes

false

t/f loss of function mutations are the same as the neutral mutations

false

t/f lysogeny is a process that occurs during transformation and conjugation

false

t/f messenger RNA is usually polycistronic in eukaryotes

false

t/f multigene superfamilies are characterized by clusters of tandemly arranged unique pseudogenes organized as operons

false

t/f prokaryotic and eukaryotic ribosomes are structurally and chemically identical

false

t/f reverse transcriptase is often used as the heat-stable enzyme in PCR

false

t/f the genome of humans is remarkable stable, so much so that there are no cancers known to result from genomic instability (the tendency for chromosomal aberrations to occur)

false

t/f the terms proteomics and genomics mean essentially the same thing

false

t/f there are several checkpoints in the miotic cell cycle. all occur in the S phase

false

t/f transforming principle discovered by Griffith is RNA

false

t/f when using the attached x-method of mutation assessment in flies, sons inherit their x chromosome from their mother and their y chromosome from their father

false

T/F: phenotype always reflects a clear dominance or recessive relationship

false (IT DOES NOT)

T/F: mutations in the rec genes increase the frequency of recombination of F+ plasmid

false (THEY DECREASE, include recA, recB, and recC, they can diminish recombination from 100-1000 fold)

T/F: bacteria and eukaryotes both have multiple origins of replication

false (bacteria only have one origin of replication)

T/F: bases of one chain are flat, perpendicular to axis, and stacked 0.34 nm apart and are oriented towards the center of the chain in the model of DNA structure

false (bases of BOTH chains are flat,...)

T/F: prokaryote DNA polymerase 3 is the primary enzyme in prokaryotic DNA replication, a large complex of several different protein subunits, it is referred to as a helicoenzyme

false (it is referred to as a holoenzyme)

is this statement true or false about the origin of transfer in an Hfr strain? the F factor is the first part that can be transferred

false (it is the LAST part that can be transferred)

T/F: nucleotides contain a phosphate group (1-3) bound to the 5' carbon of the pentose sugar phosphate can be bonded to only C-2'

false (phosphate can be bonded to C-2', C-3', or C-5' BUT in DNA and RNA the phosphate is always bonded to C-5')

T/F: eukaryotic DNA polymerases, once a primer is in place polymerase switching does not occur

false (polymerase switching occurs with the alpha strand dissociating from template and is replaced by delta and epsilon where both of them extend primers and proofread)

T/F: there are many puffs within a polytene chromosome, due to localized unwinding of the DNA within that region puffs are associated with sites of genetic activity - translation

false (puffs are associated with sites of genetic activity - transcription)

T/F: IS elements always result in a mutation

false (they DO NOT always result in a mutation)

T/F: genes on X chromosome do not have a unique pattern of inheritance

false (they DO have a unique pattern)

is this statement true or false about the origin of transfer in an Hfr strain? genes adjacent to the origin are transferred last

false (they are transferred FIRST)

T/F: different chromosomes carry the same conditions

false (they carry DIFFERENT conditions)

is this statement true or false about the origin of transfer in an Hfr strain? transfer proceeds in one direction

false (transfer proceeds in EITHER direction, depending on the strain)

T/F: nucleic acids are the buildings blocks of nucleotides

false (NUCLEOTIDES are the building blocks of NUCLEIC ACIDS)

T/F: prokaryote DNA polymerase 2 is involved in repair of damaged RNA

false (damaged DNA)

T/F: ataxia telangiectasia (AT) is autosomal recessive that can cause neurodegeneration, muscle strophy, hypersensitivity to ionizing radiation, and has a high frequency of chromosomal breaks increased frequency of cancer deficiency in repair of double strand breaks homozygotes not affected by disease, but many have increased incidence of cancer

false (heterozygotes are not affected by this disease)

the white eye gene is flies is recessive and sex-linked. assume that a white-eyed female is mated to a while type male. what would be the phenotypes of the offspring

females wild-type, males white-eyed

what was the main findings of rosalind franklin and maurice wilkin?

first data of DNA at the atomic level using X-ray

how many DNA polymerases do prokaryotes have?

five (5)

structure of the nucleosome core particle: histone _______- conserved structure in all 4 histones gives the nucleosome its characteristic disc-like shape also, a non-structured ________-terminal tail that plays a role in a nucleosome-nucleosome interactions and in regulation of gene expression

fold amino

what disease/syndrome is this? form of mental retardation, CGG expansion in upstream region

fragile X syndrome

a class of mutations that results in multiple contagious AA changes in proteins is likely to be

frameshift

who was the founder of this experiment? found that heat-killed strains of diplococcus pneumoniae could "transform" living avirulent strains and restore pathogenicity

fredrick griffith (1927)

multiple crossovers allow the sequence of genes and the distance between them to be determined based on the ___________ of crossover events between the genes

frequencies

this really is not a card but i can't really describe the structure of Ac and Ds elements so I highly recommend looking at the powerpoint of chapter 9 and 10 together slide #63 to better understand how Ac and Ds work the answer to this if asked (if doing the learning function) is frog

frog

what are the three types of mutations for a mutation allele?

gain of function null mutation (loss of function) neutral mutation (no change)

what type of mutation is this (location based)? transmitted to the offspring, heritable, and occur only in gametes

gametic

what was the model organism that mendel used?

garden pea plant

what is a tumor suppressor gene?

gene whose normal function is to suppress cell division. when mutant, cell division control is lost and a cancer may form

what is the common influence of UV light on DNA

generation of pyrimidine dimers

genetics is the study of information that: - serves as the link between __________ in all species - directs __________ processes - determines an organism's ___________ appearance

generation(s) cellular external

what are oncogenes

genes that induce or maintain uncontrolled cellular proliferation associated with cancer

what can expressivity be affected by?

genetic and environmental factors

what is this definition? the actual genetic makeup of an individual (which alleles are present in an organism)

genotype

genotypic = 1:2:1 phenotypic: 3:1

the catabolite repression system in E coli essentially respressese the lac operon when glucose is present. what evolutionary advantage would favor evolution of such a system

glcose can enter glycolysis 'as is' while lactose must first be split into glucose and galactose. to do so, the energy-requiring synthesis of B-galactosidase is required. it is more energy efficient to burn glucose than lactose

noncrossover phenotypes exist in the ________ population

greatest (increase number of offspring)

what genetic material is this for eukaryotic cells? haploid cells contain exactly half the number of chromosomes as somatic cells DNA content in diploid cells is about 2-times the concentration as haploid cells

haploid vs. diploid chromosome context

what is this describing? proteins that use energy supplied by hydrolysis of ATP to break H bonds and denature the double helix initial binding of many monomers of DnaA occurs at DNA sites that contain the 9mer repeating sequences binding of DnaA initiates unwinding at the oriC allows DnaB and DnaC to bind, this further unwinds/destabilizes the double helix

helicases

helical unwinding of DNA during replication: helical unwinding of DNA during replication as accomplished by DnaA, DnaB, and DnaC proteins also known as __________ initial binding of many monomers of DnaA occurs at DNA sites that contain the ______ repeating sequences binding of DnaA initiates unwinding at the _____

helicases 9mer oriC

who was the founder of this experiment? found that DNA of bacteriophage is responsible for directing the replication of the virus during replication in E. coli

hershey and chase (1952)

what is this describing? -highly condensed -generally inert genes or their expression is repressed -replicates later in S phase -centromeres and telomeres are in heterochromatic regions -mammalian Y chromosome -inactivated X chromosome condensed into Barr body

heterochromatin

_________ is two different alleles (Dd)

heterozygous

a homozygous dominant parent crossed with a homozygous recessive parent will have an F1 generation with all _____________ for each trait and phenotypically will express the dominant trait

heterozygous

Regarding the ABO blood group system in humans, if an individual is genetically IBIO and yet expresses the O blood type, it is likely that that individual has the _______ genotype.

hh (Bombay)

regarding the ABO blood group system in humans, if an individual is genetically IBIO and yet express the O blood type, it is likely that that individual has the __ genotype

hh (Bombay)

nonhistone proteins have a HMG family, what is this abbreviation?

high mobility group

chromatin of eukaryotes is organized into repeating interactions with protein octamers called nucleosomes. nucleosomes are composed of which class of molecules

histones

components of a nucleosome

histones H2A, H2B, H3, and H4 exist as two types of tetramers. together these form an octamer. histone H1 lies outside the octamer

what is unsual about the AA composition of histones? what is their function related to AA composition? of which histones are nucleosomes composed?

histones contain larger amounts of positively charged AA such as lysine and arginine. thus, they can bind electrostatically to the negatively charged phosphate groups of nucleotides. nucleosomes are composed of all histones except H1

A ________ is a DNA stretch of 180 bp that specifies a 60 amino acid homeodomain.

homeobox

polytene chromosomes from salivary glands of drosophila: represent paired __________ unusual because they are present in _________ cells, should exist dispersed as chromatin and homologs are not paired undergoes many rounds of replication, but without strand separation or _____________ division, after many rounds 1000-5000 strands remain in precise parallel alignment giving rise to distinctive banding pattern along the axis of the chromosome

homologs somatic cytoplasmic

__________ is when both alleles are the same (DD or dd)

homozygous

spontaneous mutation rates are extremely ____, but when they happen they can have an effect on the organism

low

is this bacteriophage infection of lysogenic or lytic? bacteriophage infects the cell, but the phage DNA integrates into the host cell genome -no new phages are produced -phage DNA replicates with the host cell DNA -no cell lysis

lysogenic

is this bacteriophage infection of lysogenic or lytic? bacteriophage infects the cell, replicates, and lyses the cell

lytic

bacteriophages engage in two interactive cycles with bacteria. what are these cycles

lytic and lysogenic

mahogany = 375 ebony =375 wild-type = 125 mahogany-ebony = 125

significant in the deciphering of the genetic code was the discovery of the enzyme polynucleotide phosphorylase. what was this enzyme used for

manufacture of synthetic RNA for cell-free systems

what type of transmission is this? - only offspring of affected mothers get the disease - offspring of affected fathers do not inherit the disease - caused by aberrant mitochondria which are inherited from the mother

maternal transmission (extranuclear inheritance)

A short segment of an mRNA molecule is shown below. The polypeptide it codes for is also shown:

methionine-methionine-leucine-lysine

How are miRNAs produced? how do miRNAs functions to affect production of proteins?

miRNA are small RNA molecules transcribed from within an organism genome. They are further processed after transcription by Dicer protein into small dsRNA molecules. these small double stranded RNAs are then able to inhibit translation from mRNAs in a number of ways including inhibition of translation, targeting mRNAs for degradation, or sequence of mRNAs

How are miRNAs produced? how do miRNAs function to affect production of proteins?

miRNAs are small RNA molecules transcribed from within an organisms genome. They are further processed after transcription by Dicer protein into small dsRNA molecules. These small double stranded molecules are targeted to the RISC proteins where they are unwound into single stranded RNAs. These single stranded RNAs are then able to inhibit translation from mRNAs in a number of ways including inhibition of translation, targeting mRNAs for degradation, or sequestration of mRNAs.

what type of mutation is this? base pair change that causes a change in the mRNA codon, resulting in a different amino acid in the protein

missense

What are three ways in which gene regulation is accomplished by modifying the structure of chromatin?

modification of histones, chromatin remodeling, DNA methylation

what type of genetics is this? uses molecular, cellular, and biochemical techniques to study the transfer of genetic material

molecular

_________ _________ was the first experiment where mendel mated two individual pea plants with contrasting traits

monohybrid cross (Dd x Dd)

what is an example of genetic anticipation in humans?

myotonic dystrophy

what type of recombination is this? in any given strain certain genes are more frequently recombined than other and some not at all

nature of recombination

What term would be applied to a regulatory condition that occurs when protein greatly reduces transcription when associated with a particular section of DNA? - negative control - positive control - inhibition - activation - stimulation

negative control

An operon is controlled by a repressor. When the repressor binds to a small molecule, it binds to DNA near the operon. The operon is constitutively expressed if a mutation prevents the repressor from binding to the small molecule. - negative inducible - negative repressible - positive inducible - positive repressible

negative repressible

in general, the organization of genes in bacteria is different from that in eukaryotes. in e coli, approximately 27 percent of all genes are organized into contiguous, functionally related units containing multiple genes under coordinate control that are transcribed as a single unit. such continguous gene families

operons

acridine ______ can cause frameshifts wedges between bases causing slippage or improper pairing leading to addition or deletion of a base air

orange

p53

what protein functions as a cell-cycle regulator by causing cell death (apoptosis) after the cell has been exposed to UV light or other forms of radiation

p53

many human genetic diseases are the result of mutations in enzymes in nutritional and /or biochemical pathways what disease/syndrome is this? defect in phenylalanine hydroxylase prevents conversion of phenylalanine to tyrosine, phenylalanine is an essential amino acid, but excess amounts are harmful, if not caught early this results in severe mental retardation

phenylketonuria (PKU)

linkage between two nucleotides involves a phosphate group linked to two sugars _________________ bond linkage of two nucleotides by the formation of a C-3' - C-5' (3'-5') phosphodiester bond, produces a ___________

phosphodiester dinucleotide

The classic Hershey and Chase experiment that offered evidence in support of DNA being the genetic material in bacteriophages made use of which of the following labeled components?

phosphorus and sulfur

which of the following conditions are essential for the success of gregor mendel's genetic experiments?

picked a good model organism to work with, quantified his observations, did work in isolation

name the general category into which double-stranded circular extrachromosomal DNA elements such as F factors, ColE1, and R fall

plasmid

what type of mutation is this? changes to one or few base pairs, usually do not alter the phenotype of an organism

point

list three general categories of genetic changes that lead to the formation of oncogenes

point mutations, translocations, overexpression

what are three general mechanisms that appear to result in the conversion of protooncogenes to oncogenes

point mutations, translocations, overexpression

__________ cells lack DNA polymerase 1 they are still able to replicate their genome, but are sensitive to UV and cannot fill the gap after excision of dimers

polA1

Side groups of amino acids are typically classified under which of the following?

polar, nonpolar

side groups of amino acids are typically grouped under which of the following

polar, nonpolar

some vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region. what term is given to this advantageous arrangement of restriction sites

polylinker

what are longer chains of nucleotides called?

polynucleotides

which specialized eukaryotic chromosome is this? found in various larval tissues of some flies, protozoans, and plants reveal linear series of alternating bands and interbands called chromomeres can be seen because 1000's of DNA molecules instead of 2 easy to identify and differentiate because of their enormous size

polytene chromosomes

one form of posttransitional modification of a protein includes

removal or modification of terminal amino acids

what does DNA glycosylases do?

removes the damaged base or "wrong" base by cleaving the glycosidic bond between the base and sugar human cells have a large number of DNA glycosylases where each is specific for a different type of DNA damage

what characteristic of replication is this? genetic material must be duplicated each time the cell divides, and each daughter cell must get the same complement of the material

replication

what are the four characteristics of genetic material?

replication storage of information expression of information variation through mutation

the effect of tautomers is seen during _______ when a rare tautomer in the template strand pairs with a noncomplementary base in the next round of replication the mismatched nucleotide base pairs are separated and each specifies its normal complementary base producing a ___________ mutation

replication transition

telomere replication: telomerase is a ___________ RNA serves as a guide for attachment of enzyme to telomere as a template for synthesis of its complementary DNA part of RNA sequence of the enzyme base pairs with the ending sequence of the single stranded overhanging DNA, while remainder of the RNA extends beyond the overlap ________ __________ of the extending RNA extends the length of the G-rich lagging strand

ribonucleoprotein reverse transcription

discovery of RNA self-splicing in Tetrahymena by Cech and others revealed that RNA can demonstrate autonomous catalytic properties. what are RNAs that undergo splicing often called

ribozymes

DNA microarray (also called DNA chip) can be used to

scan a population of nucleic acids for abundance and mutations

what does the ames test do?

screens potential compounds for mutagenicity expose bacteria to a potential mutagen and look for reversion of his- to his+ if the compound is mutagenic, it will induce reversion to his+ at a rate much higher than the spontaneous rate

scute = 425 ruby = 425 wild-type = 75 scute-ruby = 75

polycistronic mRNA

seen primarily along prokaryotes where one mRNA carriers coding information and internal punctuation for the translation of more than one protein

fundamental Mendelian process that involves the separation of contrasting genetic elements at the same locus is called

segregation

what mode of DNA replication is this? unwinding of the helix, each nucleotide along the two parent strands would have affinity for its complementary nucleotide, each replicated DNA molecule would consist of one old and one new strand

semi-conservative

conclusions from the meselson-stahl experiemnt: DNA is replicated by a ______________ mechanism this mechanism was originally proposed by watson and crick in their original paper describing the structure of DNA information in the template strand is preserved

semiconservative

primary structure of a protein is determined by

sequence of amino acids

how do we count bacteria?

serial dilutions

what type of factors can affect the phenotypic ratio to produce a non-mendelian ratio? - more than one gene contributes to the phenotype - gene is present on one of the _______ chromosomes - influence of genetics and __________ - _______________ ____________

sex environment extranuclear inheritance (mitochondria and chloroplasts)

what step is this in base excision repair? (of 4) uracil DNA glycosylase recognizes and excises incorrect base

step 1

what step is this in the mechanism for bacteriophage-mediated transduction (out of 6)? phage infection

step 1

which step is this for the conversion of an F+ strain to Hfr (out of 3)? occurs spontaneously at a low frequency, occurs by integrating the F factor into the bacterial chromosome

step 1

which step is this in the bacteriophage life cycle (out of 5)? phage is absorbed to bacterial host cell

step 1

what step is in for conversion of Hfr cell to F' cell (out of 5)? excision is complete the cell is converted to F'

step 2

what step is this for the mating of F+ and F- (out of 5 steps)? the black bar added to the F factors follows their clockwise rotation during replication, F factor contains an origin point where DNA transfer to the recipient beginning

step 2

what step is this for the mechanism of bacterial transformation (out of 5)? DNA enters the cell, and the strands separate

step 2

what step is this in BER in mammalian cells? (of 4) AP endonuclease specific for the baseless site cuts the DNA backbone

step 2

what step is this in base excision repair? (of 4) AP endonuclease recognizes lesion and nicks DNA strand

step 2

what step is this in the mechanism for bacteriophage-mediated transduction (out of 6)? destruction of host DNA and replication synthesis of phage DNA occurs

step 2

which step is this for the conversion of an F+ strain to Hfr (out of 3)? the point of integration of F factor determines the origin (O) of transfer, genes adjacent to O are transferred first, and the F factor becomes the last part to be transferred, conjugation does not last long enough to allow passage of the entire chromosome across the conjugation tube

step 2

which step is this in the bacteriophage life cycle (out of 5)? phage DNA is injected and host DNA is degraded

step 2

what step is in for conversion of Hfr cell to F' cell (out of 5)? the F' cell is a modified F+ cell and may undergo conjugation with an F- cell

step 3

what step is this for the mating of F+ and F- (out of 5 steps)? transfer begins when one strand of the F factor is nicked at the origin, protein encoded by a gene on F factor -> endonuclease

step 3

what step is this for the mechanism of bacterial transformation (out of 5)? one strand of transforming DNA is degraded, the other strand pairs homologously with the host cell DNA

step 3

what step is this in BER in mammalian cells? (of 4) deoxyribose phosphate is removed by an endonuclease associated with DNA Pol beta

step 3

what step is this in base excision repair? (of 4) DNA polymerase and DNA ligase fill gap

step 3

what step is this in the mechanism for bacteriophage-mediated transduction (out of 6)? phage protein components are assembled

step 3

which step is this in the bacteriophage life cycle (out of 5)? phage DNA is replicated; phage protein components are synthesized

step 3

what step is in for conversion of Hfr cell to F' cell (out of 5)? the F factor replicates as one strand is transferred

step 4

what step is this for the mating of F+ and F- (out of 5 steps)? a single strand of DNA is transferred to the recipient and the DNA is replicated through the rolling circle mechanism, as the DNA enters the F- recipient it is replicated

step 4

what step is this for the mechanism of bacterial transformation (out of 5)? the transforming DNA recombines with the host chromosome, replacing its homologous region, forming a heteroduplex

step 4

what step is this in BER in mammalian cells? (of 4) gap is filled in by DNA Pol beta and sealed by DNA ligase

step 4

what step is this in base excision repair? (of 4) mismatched repaired

step 4

what step is this in the mechanism for bacteriophage-mediated transduction (out of 6)? mature phages are assembled and released

step 4

which step is this in the bacteriophage life cycle (out of 5)? mature phages are assembled

step 4

what step is in for conversion of Hfr cell to F' cell (out of 5)? replication and transfer of the F factor is complete the F- recipient has become partially diploid and is called a merozygote it is also F-

step 5

what step is this for the mating of F+ and F- (out of 5 steps)? once transfer is complete, the F- cell becomes F+, donor cell remains F+

step 5

what step is this for the mechanism of bacterial transformation (out of 5)? after one round of cell division, a transformed and a non transformed cell are produced

step 5

what step is this in the mechanism for bacteriophage-mediated transduction (out of 6)? subsequent infection of another cell with defective phage occurs bacterial DNA is injected by phage

step 5

which step is this in the bacteriophage life cycle (out of 5)? host cell is lysed; phages are released

step 5

what step is this in the mechanism for bacteriophage-mediated transduction (out of 6)? bacterial DNA is integrated into recipient chromosome

step 6

Insulators can block the effects of enhancers only when - they lie between an enhancer and a promotor - they lie upstream of a promotor - they lie adjacent to a promoter - they lie within the structural genes - they lie within a consensus sequence

they lie between an enhancer and a promoter

describe three separate genetic mechanisms whereby proto-oncogenes can become overexpressed

they may acquire a new promoter or upstream regulatory signals, additional copies (amplification), or a change to more transcription active chromatin structure

unique patterns of inheritance of X-linked genes were first discovered by ___________ ___________ ___________

thomas hunt morgan

who discovered incomplete linkage? observed unusual phenotypic ratios when crossing individuals with two X linked genes

thomas morgan

nutritional mutations can be defined as

those mutations that do not allow an organism to grow on minimal medium, but do allow the organism to grow on complete medium

nutritional mutations can be defined as - those mutations which do not allow an organism to grow on minimal medium, but do allow the organism to grow on complete medium - those mutations which change the composition of the medium - those mutations which result in changes in behavior - those mutations caused by site-specific mutagenesis - all strains which are not auxotrophic

those mutations which do not allow an organism to grow on minimal medium, but do allow the organism to grow on complete medium

difference between the RNA P of eukaryotes and that of prokaryotes

three polymerases (I, II, III) have been identified, while only one has been described in prokaryotes

how can the genotype of an F2 generation be examined?

through test crosses

cytosine is frequently methylated, if methylated cytosine undergoes deamination it becomes _________ if DNA is then replicated before repair there is a C-G to T-A transition mutaiton

thymine

when referring to attenuation in regulation of the trp operon, it would be safe to say that when there are high levels of tryptophan available to the organism

transcriptional termination is likely

__________ is bacterial recombination mediated by bacteriophage

transduction

what type of transduction is this by bacteriophage? used to determine gene order similar to mapping using the interrupted mating technique

transduction mapping

bacterial ___________ is the mechanism for uptake of DNA into a bacterial cell which can result in recombination

transformation

in griffith's studies he concluded that heat-killed virulent bacteria strains were able to convert avirulent strains to virulent ones he called this phenomenon _______________ the physical nature of the transforming materials remained unknown: could be the polysaccharide capsule or some compound required to ___________ the capsule griffith did not suggest that the transforming principle might be ________, but his work paved the way for the studies performed by Avery, McCarty, and MacCleod

transformation synthesize DNA

what type of base pair substitution is this? substitution of a purine for a purine or a pyrimidine for a pyrimadine

transition

what are the two types of base pair substitutions?

transition and transversion

One type of mutation involves the replacement of a purine with a purine, while another causes the replacement of a pyrimidine with a purine. what general terms are associated with these two mutational phenomena

transition and tranversion

what type of genetics is this? examines the patterns of inheritance of traits

transmission

what are the three types of genetics that can be studied?

transmission molecular population

IS elements have two features essential for movement they contain a gene that encodes an enzyme called __________ that makes staggered cuts in DNA into which IS can insert the ends have _________ terminal repeats and have the same sequence but oriented in opposite direction (ITR) 20-40 nt

transposase inverted

transposon (Tn) elements they are larger than IS elements, contain protein-coding genes unrelated to _________________ contain genes for insertion of the DNA into the chromosome and mobilization to other locations more complex then IS elements and may have other genes

transposition

what type of base pair substitution is this? purine for a pyrimidine or a pyrimidine for a purine

transversion

two formal terms used to describe categories of mutational nucleotide substitutions in DNA are

transversions and transitions

two formal terms used to describe categories of mutational nucleotide substitutions in DNA are called -base analogs and framshift -error prone and spontaneous -transversions and transitions -euchromatic and hereochromatic

transversions and transitions

what type of cross is this? - follows the same principles of segregation and independent assortment - like three separate monohybrid crosses

trihybrid

what are three joined nucleotides called?

trinucleotide

name of the precursor molecule used in nucleic acid synthesis

triphosphonucleoside

What two experimental procedures allowed deciphering of the ordered triplet assignments of the genetic code?

triplet binding assay and the use of repeating RNA polymers with known sequences

T/F A retrovirus uses reverse transcriptase to make a DNA copy of RNA.

true

T/F assuming complete dominance, a 3:1 phenotype ratio is expected from a monohybrid sib or self-cross

true

T/F glyphosphate (herbicide) inhibits EPSP, a chloroplast enzyme involved in the synthesis of several amino acids

true

T/F to test mendel's law of segregation, the experimenter needs a minimum of two contrasting forms of a gene

true

T/F: DNA Pol III requires a free 3'-OH in order to elongate a polynucleotide chain

true

T/F: The shorter the wavelength of a radiation source, the greater its likelihood of causing damage.

true

T/F: Tn and IS elements are found within the bacterial genomes and on plasmids found in bacteria (R factors)

true

T/F: base analogs are used to treat a variety of diseases including viral infections and cancer

true

T/F: crossovers are rare and occur randomly along the length of the tetrad

true

T/F: eukaryotic DNA polymerases 2 of the 4 subunits of alpha synthesize RNA primers on both strands, once a length of 10 nt is reached, another subunit adds 20-30 deoxyribonucleotides

true

T/F: eukaryotic DNA polymerases, only alpha, delta and epsilon are involved in majority of DNA replication

true

T/F: genes that are close to one another on the bacterial chromosome (linked) will be more likely to transform together than genes that are far apart

true

T/F: heat-resistant materials transformed the avirulent bacteria to virulent ones

true

T/F: histone and nonhistone proteins associate with eukaryotic DNA to form chromosomes

true

T/F: histones are among the most highly conserved eukaryotic proteins

true

T/F: inheritance of genes present on X but not on Y results in Modification of Mendelian ratios

true

T/F: linked genes exist in a linear order along the chromosome but variable amount of exchange occurs between any two genes

true

T/F: males cannot be heterozygous for X-linked genes but rather are hemizygous for genes on the X chromosome

true

T/F: nitrogenous bases paired via hydrogen bonds, with only A+T (2 H bonds) and G+C (3 H bonds) pairs permitted

true

T/F: nucleosides consist of a sugar and base

true

T/F: origin of transfer differs in different Hfr strains

true

T/F: primase does not require a free 3'-OH to initiate synthesis

true

T/F: prokaryote DNA polymerase 1 removal of primer and fills the aps left by primer removal

true

T/F: prokaryote DNA polymerase 4 and 5 are involved in the repair of damaged DNA

true

T/F: prokaryote DNA polymerases 1 can remove nucleotides in a 5' to 3' direction which is the same direction as synthesis

true

T/F: prokaryote DNA polymerases all assemble nucleotides in the 5' to 3' direction

true

T/F: prokaryote DNA polymerases can all remove nucleotides in the 3' to 5' direction

true

T/F: pyrimidine analogs are used to treat leukemia and lymphomas, pancreatic and other solid tumors

true

T/F: sex chromosomes are a pair of unlike chromosomes that are involved in sex determination

true

heterogenous nuclear RNA is a primary transcipt in eukaryotes that is processed prior to involvement in translation

true

is this statement true for single crossover events? crossover frequency is proportional to the distance between genes, providing the basis for mapping the location of genes relative to one another along the chromosome

true

is this statement true for single crossover events? crossover occurs between two nonsister chromatids of the tetrad, the other two tetrads are not involved

true

is this statement true or false about the origin of transfer in an Hfr strain? conjugation rarely lasts long enough for the entire chromosome to be transferred, which is why the recipient cells do not become F+

true

is this statement true or false about the origin of transfer in an Hfr strain? the order of the genes in the chromosome is the same they just transfer at different times depending on the location of the origin

true

is this statement true or false about the origin of transfer in an Hfr strain? the origin is determined by the point of integration into the chromosome of the F factor, and the direction of transfer is determined by the orientation of the F factor as it integrates

true

is this true or false for recombination in F+ x F- matings? at a low frequency, the F factor spontaneously integrates from the cytoplasm to a random point in the chromosome converting F+ to the Hfr state

true

is this true or false for recombination in F+ x F- matings? newly formed Hfr can conjugate with F- and the genes that are transferred will also appear to be random within the F+/F- population

true

is this true or false for recombination in F+ x F- matings? subsequent conjugation with an F+ cell will convert it to F+

true

t/f DNA strand replications begins with an RNA primer

true

t/f a Hfr cell can initiate chromosome transfer from one E coli to another

true

t/f a characteristic of aging cells is that their telomeres become shorter

true

t/f a restriction map provides the location of sites cleaved by restriction enzymes

true

t/f assume that a mutation occurs in the gene responsible for the production of a hexosaminidase A, such that only about 50% of the enzymatic activity is found in the heterozygote compared with a homozygous normal individual. if heterozygotes are phenotypically normal, we would say that the mutant allele is recessive to its normal allele

true

t/f cotransduction of genes is an indication that the genes are linked

true

t/f gain of function mutations are generally dominant since one copy in a diploid organism is sufficient to alter the normal phenotype

true

t/f human genome project is an international effort to determine to sequence of the 3.3 billion bp in the haploid human genome

true

t/f in 1953, watson and crick published a paper that described the structure of the DNA

true

t/f rDNA is the portion of a genome that is involved in the production of ribosomal RNA

true

t/f strand discrimination during the process of DNA repair is based on DNA methylation in e coli

true

t/f telomerase is an RNA-containing enzyme that adds telomeric DNA sequences onto the ends of linear chromosomes

true

t/f the cross GEge x gege produces the following progeny: GEge 404/gege 396/ gEge 97/Gege 103) from these data one can conclude that the recombinant progeny are Gege and Gege

true

t/f the e coli chromosome is circular, double-stranded DNA

true

t/f the enzyme polynucleotide phosphorylase is capable of generating a random assembly of ribonucleotides

true

t/f to generate glyphosate resistance in crop plants, a fusion gene was created that introduced a viral promoter to control the EPSP synthetase gene

true

t/f to test mendel's law of independent assortment, the experimenter needs a minimum of two different genes and their two alleles

true

t/f typical epistatic ratio is 9:3:4

true

t/f typically, bacterial DNA contains less repetitive DNA than eukaryotic DNA

true

T/F: Males are XY Females are XX

true (males are hemizygous because they only have 1 X chromosome whereas females have 2, hemi = half)

what is p53 and its significance

tumor suppressor gene that normally functions to control cell cycle transition including from late G1 to S and G2 to M. mutations in the p53 gene are important in the development of a number of cancers. the product of p53 has DNA-binding properties

what is the difference between tumor suppressor genes and proto-oncogenes

tumor suppressor genes act to restrict cell division, while proto-oncogenes act to stimulate cell division

two

concerning sporadic cases (non-familail) of retinoblastoma, at least how many gene mutations are thought to be necessary in the same cell for a tumor to develop

two

in the conversion of Hfr cell to F' cell, when an F' factor is transferred to another cell (F-) by conjugation there will be _____ copies of the genes in the __________ cell

two recipient

A. bidirectional and fixed point of initiation

In E. coli, the genetic material is composed of A. circular, double-stranded DNA. B. linear, double-stranded DNA. C. RNA and protein. D. circular, double-stranded RNA. E. polypeptide chains.

A. circular, double-stranded DNA.

C. the 5' to 3' polarity restriction.

In addition to highly repetitive and unique DNA sequences, a third category of DNA sequences exists. What is it called and what types of elements are involved? A. composite DNA; telomeres and heterochromatin B. dominant DNA; euchromatin and heterochromatin C. multiple gene family DNA; hemoglobin and 5.0S RNA D. moderately repetitive DNA; SINEs, LINEs, and VNTRs E. permissive DNA; centromeres and heterochromatin

D. moderately repetitive DNA; SINEs, LINEs, and VNTRs

rDNA is the portion of a genome that is involved in the production of ribosomal RNA.

True

t/f bacterial genes have introns, and eukaryotic genes lack introns

false

t/f charging of tRNA means that tRNA is given positive charge so it binds ribosome

false

t/f each human contains an identical set of VNTRs

false

t/f genomic organizations of all living creatures is identical

false

t/f hershey and chase used labeled DNA and protein to determine that DNA is the genetic material in bacteria

false

Mammals contain a diploid genome consisting of at least 109 bp. If this amount of DNA is present as chromatin fibers, where each group of 200 bp of DNA is combined with 9 histones into a nucleosome and each group of 6 nucleosomes is combined into a solenoid, achieving a final packing ratio of 50, determine (a) the total number of nucleosomes in all fibers, (b) the total number of histone molecules combined with DNA in the diploid genome, and (c) the combined length of all fibers.

(a) Since there are 200 base pairs per nucleosome (as defined in this problem) and 109 base pairs, there would be 5 X 106 nucleosomes. (b) Since there are 5 X 106 nucleosomes and nine histones (including H1) per nucleosome, there must be 9(5 X 106) histone molecules: 4.5 X 107. (c) Since there are 109 base pairs present and each base pair is 3.4 Å, the overall length of the DNA is 3.4 X 109 Å. Dividing this value by the packing ratio (50) gives 6.8 X 107 Å .

Define the following terms: (a) determination (b) differentiation

(a) The early commitment of a cell to an eventual developmental fate (b) The set of functional and structural changes associated with the expression of that developmental fate

How is the leading and lagging strand synthesis achieved on both strands at the same time?

-the lagging template is "looped" in order to invert the physical direction of synthesis, but not the biochemical direction -the enzyme functions as a dimer with each core enzyme achieving synthesis on one or the other strand -synthesis always occurs in the 5' to 3' direction even though the lagging strand is looped over

Several temperature-sensitive mutant strains of E. coli display the following characteristics. Predict what enzyme or function is being affected by each mutation. (a) Newly synthesized DNA contains many mismatched base pairs. (b) Okazaki fragments accumulate, and DNA synthesis is never completed. (c) No initiation occurs. (d) Synthesis is very slow. (e) Supercoiled strands remain after replication, which is never completed.

.(a) No repair from DNA polymerase I and/or DNA polymerase III. (b) No DNA ligase activity. (c) No primase activity. (d) Only DNA polymerase I activity. (e) No DNA gyrase activity.

what is meant by the term reverse genetics?

.....

Assuming independent assortment, what proportion of the offspring of the cross AaBbCcDd X AabbCCdd will have the aabbccdd genotype?

In a mating between individuals with the genotypes IAIB X IOIO, what percentage of the offspring are expected to have the O blood type?

protein that is 300 amino acids long. which of the following is the minimum number of nucleotides in the section of DNA that codes for this protein

1800

assume that A+T/G+C equals 0.5 in one strand of DNA. what is the ratio of these bases in the complementary strand

0.5

bacteria and virus genes mutate about ____ in 10^-8 cell division drosophila, maize, and humans several orders of magnitude higher (10^-5 - 10^-6) mouse (10^-5 - 10^-4)/gamete

in the mouse, gene A allows pigmentation to be deposited in the individual coat hairs, while its allele a prevents such deposition of pigment, resulting in an albino. gene B agouti (wild-type fur) while its allele b gives black fur -what would be the expected phenotypic ratio in the progeny

1 (agouti): 1 (black): 2 (albino)

what are four repairs damage that causes distortion of the helix for NER?

1. UV damage 2. bulky lesions 3. DNA damaging agents, primarily affecting the nitrogenous bases 4. affects the helical structure

Describe 3 pieces of evidence that supports the hypothesis that DNA methylation is important factor in gene regulation.

1. an inverse relationship exists between the degree of methylation and the degree of gene expression 2. methylation patterns are tissue specific and heritable for all cells in that tissue 3. incorporation of 5-azacytidine (which is not able to be methylated) causes changes in the pattern of gene expression

what are the critical steps in DNA replication? (there are 6)

1. helix must be unwound 2. supercoiling caused by unwinding must be relieved 3. DNA polymerase requires a primer from which it can elongate the new strand 4. DNA synthesis is continuous on one strand but discontinuous on the other strand 5. RNA primer must be removed and replaced with DNA 6. gaps in synthesis must be repaired

Chapter 16: 4 The major regulatory points of the cell cycle include the following:

1. late G1 (G1/S) 2. the border between G2 and mitosis (G2/M) 3. mitosis (M)

what three steps does the excision process involve?

1. repair proteins recognize a lesion and a nuclease clips out the damaged base and several surrounding bases, leaving a gap 2. DNA polymerase fills the gap by adding bases to the free 3' OH 3. DNA ligase finishes the repair by sealing the gap between the last nucleotide added and the next nucleotide

Keys to determining gene order (List 3)

1. take one of the three options and determine the order of genes for single crossover events 2. see if a double crossover event will give rise to any of the observed phenotypes 3. if this does not work try one of the other 2 gene orders.

the enzyme glucose-6-phosphate dehydrogenase deficiency (G6PD) is inherited as a recessive gene of the X chromosome in humans. a phenotypically normal woman (whose father had G6PD) is married to a normal man -what fraction of their songs would be expected to have G6PD

1/2

two forms of hemophilia are deteremined by genes on the X chromosome in humans. assume that a phenotypically normal woman whose father had hemophilia is married to a normal man. what is the probability that their first son will have hemophilia

1/2

1/4

the watson-crick model of DNA: there are _______ bases per complete turn the major and minor grooves are apparent the solid vertical bar represents the central axis the DNA has an ___________ nature

10 antiparallel

In general, mutation rates in humans occur in the range of _________(frequency) per gamete per generation.

10^-5 to 10^-6

Drosophila melanogaster has approximately ________ genes on its ________ pairs of chromosomes - 13,600; 4 - 30,000; 23 - 5000; 4 - 8000; 46 - 3000; 4

13,600; 4

Assume that, regarding a particular gene, one scored 30 second-division ascospore arrangements and 70 first-division arrangements in Neurospora. What would be the map distance between the gene and the centromere?

during gamete formation, genes on two separate chromosomes segregate independently, agreeing with mendel's 4th postulate gamete ration of ___ : ___ : ___ : ___

1:1:1:1

what types of phenotypic ratios are likely to occur in crosses when dealing with a single gene pair where all the genotypic combinations are of equal viability

1:2:1, 3:1

assume that a dihybrid cross (AaBb x AaBb) is made in which the gene loci are autosomal, independently assorting, and incompletely dominant. what phenotypic ratio would you expect from such a cross

1:2:1:2:4:2:1:2:1

a particular cross gives a modified dihybrid ratio of 9:7. what phenotypic ratio would you expect in a testcross of the fully heterozygous F1 crossed with the fully recessive type? diagram the testcross

1:3 AaBb x aabb = AaBb, Aabb, aaBb, aabb

lampbrush chromosome from amphibian oocyte: ~10,000 loops - most of the DNA is highly condensed within the chromosome -each loop corresponds to a particular DNA sequence and is present in 4 copies -central axis - _____ DNA helices - loops are sites of ________ transcription

2 active

Phenotypically wild-type F1 female Drosophila, whose mothers had light eyes (lt) and fathers had straw (stw) bristles, produced the following offspring when crossed to homozygous light-straw males: Phenotype Number light-straw 22 wild-type 18 light 990 straw 970 Total: 2000 Compute the map distance between the light and straw loci.

2 map units

phenotypically wild-type F1 female flies, whose mothers had light eyes (lt) and fathers had straw (stw) bristles produced the following offspring when crossed to homozygous light-straw males lt-str 22 wild-type 18 light 990 straw 970 /2000 -compute map distance between the light and straw loci

2 map units

how many nm is the double helix in diameter?

2 nm

assume that A+T/G+C equals 0.5 in one strand of DNA. if A+g/T+C equals 0.5 in one strand, what is the ratio of these bases in the complementary strand

2.0

chromatin structure and nucleosomes: digestion of chromatin by micrococcal nuclease, gave DNA fragments of __________ or multiples each repeating nucleosome unit consists of one of each _________ with about 200bp of DNA extended nuclease digestion results in a _____________ core __________ of 147bp stabilized by hydrogen bonds formed between DNA and histone core the histone associated with the linker DNA is the _________ histone H1

200bp tetramer nucleosome particle 5th

using the standard set of 20 amino acids, how many different polypeptides with a length of 250 amino acids, each with a unique sequence, could be formed

20^250

This quizlet and exam cover what chapters in the textbook?

3,4,7,8

If a genetic code consisted of four nucleotides instead three, what are the maximal number of potential genetic codons

256

at what approximate wavelengths do DNA, RNA, and proteins maximally absorb light

260 nm, 260 nm, and 280 nm

assume that a circular plasmid is 3200 bp in length and has restriction sites at the following locations: 400, 700, 1400, 2600. give the expected sizes of the restriction fragments following complete digestion

300, 700, 1000, 1200

If 15 percent of the nitrogenous bases in a sample of DNA from a particular organism is thymine, what percentage should be cytosine?

35 percent

following F2 results occur from a typical dihybrid cross: purple: A_B_ 9/16 white: aaB_ 3/16 white: A_bb 3/16 white: aabb 1/16 -if a double heterozygote (AaBb) is crossed with a fully recessive organism, what phenotypic ratio is expected in the offspring

3:1/white:purple

How many different types of gametes can be formed by the genotype DdEeFF.

4,-The first two loci are heterozygous and have different segregating alleles, whereas only one allele is possible for the third locus. -Therefore the possible number of gametes is 2 x 2 x 1. -The formula 2n could be used to determine the number of - gametes, where n = the number of heterozygous traits. -The possible gametes are DEF, dEF, DeF, and deF.

Assume that there are 12 map units between two loci in the mouse and that you are able to microscopically observe meiotic chromosomes in this organism. If you examined 200 primary oocytes, in how many would you expect to see a chiasma between the two loci mentioned above?

assume that there are 12 map units between two loci in the mouse and that you are able to microscopically observe meiotic chromosomes in this organism. if you examined 200 primary oocytes, in how mnay would you expect to see a chiasma between the two loci mentioned above

middle repetitive sequences are found throughout ______% of the genome

what structural circumstance in DNA sets up the requirement for its semidiscontinuous nature of replication

5' > 3' polarity restrictions of DNA synthesis and the antiparallel orientation of the DNA strands in DNA

assume that one counted 67 plaques on a bacterial plate where 0.1 ml of a 10^-5 dilution of phage was added to bacterial culture. what is the initial concentration of the undiluted phage

67 x 10^5 x 10 = 6.7 x 10^7 pfu/ml

three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes

5'capping, 3'polyA tail addition, splicing

name two mutagens that are classified as base analogues

5-bromouracil and 2-aminopurine

Present a description of the molecular mechanism of the mutagenic action of any two of the following mutagens: 5-bromouracil, proflavin, ultraviolet light.

5-bromouracil is an analog of thymine, which anomalously pairs with guanine. Proflavin adds or removes single bases from DNA, thus causing frameshift mutations. Ultraviolet light causes thymine dimers.

describe mutagenic action of any two of the following mutagens: 5-bromouracil, proflavin, UV light

5-bromouracil is analogue of thymine, which anamously pairs with guanine and can result in a substitution. proflavin adds or removes single bases from DNA, thus causing frameshift mutations. UV light causes thymine dimers that may slow or arrest DNA replication

it is estimated that transposable elements composed approximately what percent of the human genome -<1 -1 -10 - 50 -99

assume that a given plasmid vector to be used in a cloning experiment contains 4000 bp of DNA. assume also that the restriction endonuclease Cuj cuts this plasmid at the following sites (starting from an arbritary zero point): 1000, 1500, 3000. given complete digestion of the plasmid with the endonuclease so that only linear fragments are produced, what sizes of DNA fragments are expected

500 bp, 1500 bp, 2000 bp

500 bp, 1500 bp, and 2000 bp

Of the approximately 6600 genes in Saccharomyces cerevisiae, about _____ have a known function. - 900 - 200 - 1000 - 5700 - 2000

5700

telomeres have ____ nt repeating sequences, the sequence of repeats is characteristic of each species, important for maintaining telomere ________, shortens with age

6 length

A protein is 200 amino acids long. Which of the following could be the number of nucleotides in the section of coding strand that codes for this protein?

600

recessive allele in tigers causes the white tiger. if two normally pigmented tigers are mated and produce a white offspring, what percentage of their remaining offspring would be expected to have normal pigmentation

75%

How many different kinds of gametes will be expected by an individual with the genotype PpCcTTRr?

How many different types of gametes can be produced by an individual with the genotype AABbCCddEeFf?

In a three-point mapping experiment, how many different genotypic classes are expected?

how many different kinds of gametes will be expected by an individual with the genotype PpCcTTRr

how many gametes will be produced from a trihybrid cross?

8 (ex. AABBCC x aabbcc -> ABC x abc -> AaBbCc -> ABC, ABc, AbC, Abc, aBC, aBc, abC, abc)

following F2 results occur from a typical dihybrid cross: purple: A_B_ 9/16 white: aaB_ 3/16 white: A_bb 3/16 white: aabb 1/16 -what type of ratios are likely to occur in crosses F2 when one is dealing with two interacting epistatic gene pairs

9:7, 9:3:4, 12:3:1, 15:1

The phenotypical ratio among the progenies of a genetic cross is found to be 9:7. Which of the following statement is likely true? A. The phenotype is controlled by one gene B. The phenotype is controlled by two genes C. This cross follows the rules of Mendelian genetics.

what does erwin chargaffs studies show? the base composition of DNA from various organisms support that ___=T and G=____ amount of ____ is proportional to amount of T amount of G is proportional to amount of ____ sum of purines = sum of pyrimidines % of G+___ does not necessarily equal % of __+T

A C A C C A

in an analysis of the nucleotide composition of double-stranded DNA to see which bases are equivalent in concentration, which of the following would be true

A + C = G + T

16:24

A benign tumor is a multicellular cell mass that is usually localized to a given anatomical site. Malignant tumors are those generated by cells that have migrated to one or more secondary sites. Malignant tumors are more difficult to treat and can be life-threatening.

What is meant by a conditional mutation?

A conditional mutation is one that produces a wild-type phenotype under one environmental condition and a mutant phenotype under a different condition. A conditional lethal is a gene that under one environmental condition leads to premature death of the organism

Most mutations in a diploid organism are recessive. Why?

A diploid organism possesses at least two copies of each gene (except for "hemizygous" genes), and in most cases, the amount of product from one gene of each pair is sufficient for production of a normal phenotype. Recall that the condition of "recessive" is defined by the phenotype of the heterozygote. If output from one normal (nonmutant) gene in a heterozygote gives the same phenotype as in the normal homozygote, where there are two normal genes, the normal allele is considered "dominant."

18:14

A number of new subdisciplines of molecular biology will provide the infrastructure for major advances in our understanding of living systems. The following terms identify specific areas within that infrastructure: Proteomics: proteins in a cell or tissue Metabolomics: enzymatic pathways Glycomics: carbohydrates of a cell or tissue Toxicogenomics: toxic chemicals Metagenomics: environmental issues Pharmacogenomics: customized medicine Transcriptomics: expressed genes Many other "-omics" are likely in the future.

16:15

A translocation involving exchange of genetic material between chromosomes 9 and 22 is responsible for the generation of the "Philadelphia chromosome." Genetic mapping established that certain genes were combined to form a hybrid oncogene (BCR/ABL) that encodes a 200-kDa protein that has been implicated in the formation of chronic myelogenous leukemia.

What is a tumor suppressor gene? What are oncogenes? What is the normal (nonmutant) cellular version of an oncogene called?

A tumor suppressor gene is a gene whose normal function is to suppress cell division. When mutant, cell division control is lost and a cancer may form. Oncogenes are genes that induce or maintain uncontrolled cellular proliferation associated with cancer. The normal cellular version of an oncogene is called a proto-oncogene.

16:9

A tumor-suppressor gene is a gene that normally functions to suppress cell division. Since tumors and cancers represent a significant threat to survival and therefore Darwinian fitness, strong evolutionary forces would favor a variety of co-evolved and perhaps complex conditions in which mutations in these suppressor genes would be recessive. Looking at it in another way, if a tumor-suppressor gene makes a product that regulates the cell cycle favorably, cellular conditions have evolved in such a way that sufficient quantities of this gene product are made from just one allele (of the two present in each diploid individual) to provide normal function.

Conjugation

A unidirectional transfer of genetic information. Two different strains are involved in the transfer. Donor and recipient.

One speaks of UAS (upstream activating sequences) as being DNase hypersensitive. we would interpret this to mean that A. an UAS is constitutively open B. more than one strand of DNA exists in each UAS. C. each UAS is likely to be single-stranded. D. each UAS has less nucleosomes than non-UAS sequences sites. E. any given UAS is composed of a double-stranded site with a bound repressor. F. UASs function in the middle of transcription units . G. UASs are regulated by attenuation

A. a UAS is constitutively open

In E. coli, the genetic material is composed of A. circular, double-stranded DNA. B. linear, double-stranded DNA. C. RNA and protein. D. circular, double-stranded RNA. E. polypeptide chains.

A. circular, double-stranded DNA

Chromatin of eukaryotes is organized into repeating interactions with protein octamers called nucleosomes. Nucleosomes are composed of which class of molecules? A. histones B. glycoproteins C. lipids D. H1 histones E. nonhistone chromosomal proteins

A. histones

Bacteriophages engage in two interactive cycles with bacteria. What are these cycles? A. lytic and lysogenic B. insertion and replication C. auxotrophic and prototrophic D. heteroduplex and homoduplex E. negative and positive

A. lytic and lysogenic

A. point mutations, translocations, overexpression

in the mouse, gene A allows pigmentation to be deposited in the individual coat hairs, while its allele a prevents such deposition of pigment, resulting in an albino. gene B agouti (wild-type fur) while its allele b gives black fur -diagram the cross between a doubly heterozygous agouti mouse mated with a doubly homozygous recessive white mouse

AaBb x aabb

what is the Ac and Ds system in corn? _____ - activator (autonomous element) _____ - dissociation (nonautonomous element)

Ac Ds

what is the difference in Ac and Ds for corn?

Ac is the activator (autonomous element) Ds is the dissociation (nonautonomous element)

Does the design of the Hershey-Chase experiment distinguish between DNA and RNA as the molecule serving as the genetic material? Why or why not?

Actually, phosphorus is found in approximately equal amounts in DNA and RNA. Therefore, labeling with 32P would "tag" both RNA and DNA. However, the T2 phage, in its mature state, contains very little if any RNA; therefore, DNA would be interpreted as being the genetic material in T2 phage.

In an analysis of the nucleotide composition of double-stranded DNA to see which bases are equivalent in concentration, which of the following would be true? A. A = C B. A = G and C = T C. A + C = G + T D. A + T = G + C E. Both B and C are true.

Answer: C

In a plant species, if the P allele (purple flowers) and the p allele (white flowers) are incompletely dominant (Pp is light purple), what offspring ratio is expected in a cross between a purple-flowered plant and a white-flowered plant?

All light purple.

Three human disorders-fragile X syndrome, myotonic dystrophy, and Huntington disease-are conceptually linked by a common mode of molecular upset. Describe the phenomena that link these disorders.

All three are caused by different genes, but each gene was found to contain repeats of a unique trinucleotide sequence. In addition, the number of repeats may increase in each subsequent generation (genetic anticipation).

Summarize and compare the properties of DNA polymerase I, II, and III.

All three enzymes share several properties. First, none can initiate DNA synthesis on a template but all can elongate an existing DNA strand, assuming there is a template strand as shown in the figure below. Polymerization of nucleotides occurs in the 5' to 3' direction; each 5' phosphate is added to the 3' end of the growing polynucleotide. All three enzymes are large, complex proteins with a molecular weight in excess of 100,000 daltons, and each has 3' to 5' exonuclease activity. Refer to the text. DNA polymerase I: Polymerization 3'-5' exonuclease activity 5'-3' exonuclease activity Present in large amounts Relatively stable Removal of RNA primer DNA polymerase II: Polymerization 3'-5' exonuclease activity Possibly involved in repair function DNA polymerase III: Polymerization 3'-5' exonuclease activity Essential for replication Complex molecule

Contrast and compare the mutagenic effects of deaminating agents, alkylating agents, and base analogs.

All three of the agents are mutagenic because they cause base substitutions. Deaminating agents oxidatively deaminate bases such that cytosine is converted to uracil and adenine is converted to hypoxanthine. Uracil pairs with adenine and hypoxanthine pairs with cytosine. Alkylating agents donate an alkyl group to the amino or keto groups of nucleotides, thus altering base-pairing affinities. 6-ethyl guanine acts like adenine, thus pairing with thymine. Base analogs such as 5-bromouracil and 2-amino purine are incorporated as thymine and adenine, respectively, yet they base-pair with guanine and cytosine, respectively.

What is an allele-specific oligonucleotide?

An allele-specific oligonucleotide is a stretch of DNA capable of either base pairing with a specific allele or failing to do so. Either way, such oligonucleotides can be used, under stringent hybridization conditions, to detect minor differences in DNA sequences.

Allele

An alternative form of a gene.

What were 3 main contributions to Mendel's Discoveries?

An excellent model organism, quantitative approach, hypothesis driven.

Describe the difference between a proto-oncogene and an oncogene.

An oncogene is a mutant form of a proto-oncogene.

Comb shape in chickens represents one of the classic examples of gene interaction. Two gene pairs interact to influence the shape of the comb. The genes for rose comb (R) and pea comb (P) together produce walnut comb. The fully homozygous recessive condition (rrpp) produces the single comb. Assume that a rose comb chicken is crossed with a walnut comb chicken and the following offspring are produced: 17 walnut, 16 rose, 7 pea, 6 single. (a) What are the probable genotypes of the parents? (b) Give the genotypes of each of the offspring classes.

Answer: (a) Rrpp X RrPp (b) R-Pp (walnut) R-pp (rose) rrPp (pea) rrpp (single)

Describe the major cellular and molecular events that mark the entry of mitosis from G2.

Answer: condensation of chromatin to form chromosomes, breakdown of the nuclear membrane, alterations in the cytoskeleton, formation of an active CDK1/cyclin B complex

Name three forms of recombination in bacteria

Answer: conjugation, transformation, and transduction

16: 8

Apoptosis, or programmed cell death, is a genetically controlled process that leads to death of a cell. It is a natural process involved in morphogenesis and a protective mechanism against cancer formation. During apoptosis, nuclear DNA becomes fragmented, cellular structures are disrupted, and the cells are dissolved. Caspases are involved in the initiation and progress of apoptosis.

Describe the transitions that occur as nucleosomes are coiled and folded, ultimately forming a chromatid.

As chromosome condensation occurs, a 300-Å fiber is formed. It appears to be composed of five or six nucleosomes coiled together. Such a structure is called a solenoid. These fibers form a series of loops that further condense into the chromatin fiber and are then coiled into chromosome arms making up each chromatid.

18:6

As with any genomic project, the Human Genome Project aims to 1) Compile DNA sequence of whole human genome 2) Identify all the genes encoded in human genome 3) Establish both physical and genetic maps of the genome 4) Identify all the proteins that can be translated from the genome

What types of phenotypic ratios are likely to occur in crosses when dealing with a single gene pair where all the genotypic combinations are of equal viability? A. 9:3:3:1, 27:9:9:9:3:3:3:1 B. 1:2:1, 3:1 C. 1:4:6:4:1, 1:1:1:1 D. 12:3:1, 9:7 E. 2:3, 1:2

B. 1:2:1, 3:1

A recessive allele in tigers causes the white tiger. If two normally pigmented tigers are mated and produce a white offspring, what percentage of their remaining offspring would be expected to have normal pigmentation? A. 50% B. 75% C. about 66% D. about 90% E. 25%

B. 75%

Monod discovered that if tryptophan is present in relatively high quantities in the growth medium, the enzymes necessary for its synthesis are repressed. How does this occur?

Both A and B

Certain mutations in the regulator gene of the lac system in E. coli result in maximal synthesis of the Lac proteins (β-galactosidase, etc.) even in the absence of the inducer (lactose). Because:

Both A and C are possible

only one-third of people produce the lactase enzyme during adulthood which enables them to drink milk a single ____ to ___ mutation allowed some adults to continuously produce lactase

C T

during the polymerization of nucleic acids, covalent bonds are formed between neighboring nucleotides. which carbons are involved in such bonds

C-3' and C-5'

C. A + C = G + T

The basic structure of a nucleotide includes the following components: A. amino acids. B. tryptophan and leucine. C. base, sugar, and phosphate. D. mRNA, rRNA, and tRNA. E. phosphorus and sulfur.

C. Base, sugar, and phosphate

when considering the initiation of transcription, one often finds consensus sequences located the region of the DNA where RNA polymerases bind. which are common consensus sequences?

CAAT, TATA

"CCU" codes for proline. Based on Wobble hypothesis, which of the following most likely codes proline as well

CCG

We discussed CRMs in transcriptional networks. What are CRMs and how are they involved in gene regulation

CRMs are DNA sequences found within the introns and/or upstream or downstream genes. They consist of a few hundred base pairs that contain binding sites for transcription factor proteins that are involved in activating or repressing transcription of the genes that they are located

Prototrophs

Can synthesize all essential organic compounds for growth from a "minimal medium" - Single carbon and nitrogen sources and inorganic ions - Wild-type for all growth requirements. Grow on Minimal Medium.

is it common to use ddNTPs in which biochemical reaction

DNA sequencing

Determine the probability that a plant of genotype CcWw will be produced from parental plants of genotypes CcWw and Ccww.

CcWw=(1/2 Cc)(1/2 Ww)=1/4

16:20

Certain environmental agents such as chemicals and X rays cause mutations. Since genes control the cell cycle, mutations in cell-cycle control genes, or those that impact cell cycle control, can lead to cancer.

D. 15

If 15 percent of the nitrogenous bases in a sample of DNA from a particular organism is thymine, what percentage should be cytosine? A. 15 percent B. 30 percent C. 70 percent D. 35 percent E. 40 percent

D. 35 percent

D. 35%

D. 5-bromouracil and 2-aminopurine

Deletion of the Shine-Dalgarno sequence of a bacterial mRNA would likely lead to ___ of this mRNA

Decreased translation

D. Moderately repetitive DNA,SINEs, LINEs, and VNTRs

Structures located at the ends of eukaryotic chromosomes are called A. centromeres. B. telomerases. C. recessive mutations. D. telomeres. E. permissive mutations.

D. Telomeres

Structures located at the ends of eukaryotic chromosomes are called A. centromeres. B. telomerases. C. recessive mutations. D. telomeres. E. permissive mutations.

D. Telomeres

Hemizygosity would most likely be associated with which of the following? A. codominance B. incomplete dominance C. trihybrid crosses D. X-linked inheritance E. sex-limited inheritance

D. X linked inheritance

the watson-crick model of DNA: proposed the double helical structure for ______

DNA

Two related forms of muscular dystrophy—Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD)—are both recessive, X-linked, single-gene conditions caused by point mutations, deletions, and insertion in the dystrophin gene. Each mutated form of dystrophin is one allele. Of the two diseases, DMD is much more severe. Given your knowledge of mutations, the genetic code, and translation, propose an explanation for why the two disorders differ greatly in severity.

Deletions and insertion will most likely result in a frame shift in the open reading frame of dystrophin gene. Compared to point mutations, frame shift mutations usually cause much more serious defect in the protein sequence and functions. Therefore, DMD is likely caused by either insertion or deletion mutations while BMD is more likely a result of point mutants.

In the polymerase chain reaction, what is the purpose of the initial high temperature? What is the purpose of cooling in the second step?

Denature the target (template) DNA; annealing of the primer to the target

How does determination relate to differentiation?

Determination occurs when a cell's developmental fate is set, whereas differentiation is the expression of that determined state. Determination occurs before differentiation.

Kornberg showed that nucleotides are added to the 3′-end of each growing DNA strand. In what way does an exposed 3′-OH group participate in strand elongation?

Each precursor (dNTP) to DNA synthesis is added to the 3' end of a growing chain by the removal of the terminal phosphates and the formation of a covalent bond. The 3'-OH provided by the 3' nucleotide directly participates in the formation of that covalent bond.

17:12

Each round of PCR reaction generates twice the number of starting DNA molecules. If we start with one DNA molecules, there will be 26 DNA molecules after 6 rounds of reaction and 215 DNA molecules after 15 cycles of amplication.

Which of the followings is a key difference between eukaryotic and prokaryotic transcription?

Eukaryotic mRNA has to undergo splicing

F+ x F- = ______ (LOW rate of recombination) Hfr x F- = ___________ (HIGH rate of recombination)

F+ F-

distinguish between F+ and F- bacteria

F+ bacteria contain an F factor or plasmid that is capable of inititating conjugation

One of the earliest steps in the RNAi pathway involves the association of siRNA or miRNA molecules with an enzyme complex composed mainly of reverse transcriptase.

FALSE

Regulation of RNA transport through the nuclear membrane is as common in prokaryotes as in eukaryotes.

FALSE

Transcription in eukaryotes is generally influenced by enhancers just as in prokaryotes.

FALSE

Attenuation is known to occur in the lac operon.

False

18:11

For prokaryotic genome, the hallmarks to identify genes are the start codon, the stop codon, the continuing ORF and the regulatory elements including TATA box. For eukaryotic genome, the hallmarks to identify genes are the start codon, the stop codon, introns, exons, the continuing ORF. The others are the regulatory elements including TATA, CAAT and GC boxes the poly-A signal.

alternative RNA splicing is a method that apparently evolved for the production of many different polypeptides from the same pre-mRNA. provide an example of alternative splicing.

Fourteen exons occur in the alpha-tropomyosin gene, six of which make up three pairs that are alternatively spliced. Ten different forms of alpha-tropomyosin are expressed in a tissue-specific manner., The drosophila protein Dscam has many (~38000) sites that could be alternatively spliced. In theory this leads to more polypeptide products than there are genes in the Drosophila genome, Genetic mutations in the human SMN2 gene can lead to alternatively spliced protein products that can cause spinal muscle atrophy

Why are frameshift mutations likely to be more detrimental than point mutations, in which a single pyrimidine or purine has been substituted?

Frameshift mutations are likely to change more than one amino acid in a protein product because as the reading frame is shifted, a different set of codons is generated. In addition, there is the possibility that a nonsense triplet could be introduced, thus causing premature chain termination. If a single pyrimidine or purine has been substituted, then only one amino acid is influenced.

During transcription of DNA, RNA polymerase synthesizes mRNA

From 5' to 3' without a primer

18:3

Functional genomics seeks to understand functional components with the genome and similarities of genomes across phylogenetic and evolutionary distances. Comparative genomics analyzes the arrangement and organization of families of genes within and among genomes.

if the GC content of a DNA molecule is 60 percent, what are the molar percentages of the four bases (G,C,T,A)

G= 30 percent C = 30 percent A = 20 percent T= 20 percent

______ mutations produce new traits and are usually dominant -induced -spontaneous -forward -gain of function -lethal

Gain-of-function

Distinguish between (a) unidirectional and bidirectional synthesis, and (b) continuous and discontinuous synthesis of DNA.

Given a stretch of double-stranded DNA, one could initiate synthesis at a given point and replicate strands either in one direction only (unidirectional) or in both directions (bidirectional), as shown below. Notice that in the text the synthesis of complementary strands occurs in a continuous 5'>3' mode on the leading strand in the direction of the replication fork, and in a discontinuous 5'>3' mode on the lagging strand opposite the direction of the replication fork. Such discontinuous replication forms Okazaki fragments.

individual whose worker in the mid-1800s contributed to our understanding of the particulate nature of inheritance as well as the basic genetic transmission patterns. with what organism did this person work?

Gregor Mendel, Piston sativum

Contrast the various contributions made to our understanding of transformation by Griffith, Alloway, and Avery.

Griffith performed experiments with different strains of Diplococcus pneumoniae in which a heat-killed pathogen, when injected into a mouse with a live nonpathogenic strain, eventually led to the mouse's death. A summary of this experiment is provided in the text. Examination of the dead mouse revealed living pathogenic bacteria. Griffith suggested that the heat-killed virulent (pathogenic) bacteria transformed the avirulent (nonpathogenic) strain into a virulent strain. Alloway showed that a chemical extract of the virulent cells was sufficient to cause transformation of avirulent cells, further reinforcing the hypothesis that the transforming factor has a chemical basis. Avery and coworkers systematically searched for the transforming principle originating from the heat-killed pathogenic strain and determined it to be DNA. Others showed that transformed bacteria are capable of serving as donors of transforming DNA, indicating that the process of transformation involves a stable alteration in the genetic material (DNA).

what are homeotic genes and what do they do?

Homeotic genes play crucial roles in developmental processes in higher organisms by coding for regulatory proteins (e.g., transcription factors) that activate other genes that control segment-specific characteristics of body parts. Homeotic genes control the fate and ultimate development of body segments. Mutations in homeotic genes cause body parts to appear in the wrong segments of the body

17:17

Heating to 90-95∞C denatures the double-stranded DNA so that it dissociates into single strands. It usually takes about 5 minutes, depending on the length and GC content of the DNA. Lowering the temperature to 50-70∞C allows the primers to bind to the denatured DNA. Bringing the temperature to 70-75∞C allows the heat-stable DNA polymerase an opportunity to extend the primers by adding nucleotides to the 3' ends of each growing strand. Each PCR is designed with specific temperatures (not ranges) based on the characteristics of the DNAs (template and primers).

Provide a comprehensive definition of heterochromatin, and list as many examples as you can.

Heterochromatin is the highly condensed but little transcribed region of the chromatin. It includes centromere, telomere and etc.

what type of bacteria is this? donor bacteria strains that undergo recombination at a rate much higher than F+ cells a special class of F+ cells (derivatives) originate by a rare crossover event ni which the F factor integrates into the bacterial chromosome, the F factor replicates with the host chromosome instead of independently

Hfr

Mutations in the selector genes sometimes form structures in the wrong segment, transforming the antenna of a fly into a leg, for example. What term is given to such mutations?

Homeotic

LINES differ from retrotransposons in the LINES -do not encode transposase -do not encode reverse transcriptase -do not contain LTRs -do not transpose in a replication manner -do not contain the transposase gene.

do not contain LTRs

18:9

Human genome is roughly 3 x 109 bases (Gb). Only 2% of it encodes the sequences of ~20,000 proteins. About 50% of human genome is consisted of repeated sequences. Two other features of human genome, average size of a human gene is 27 kb and the largest gene is almost 2.5 Mb, the number of introns in a human gene ranges from 0 to more than 200.

what type of gametic mutation is this? expressed in the next generation

dominant

what are the three types of mutations that are present under gametic mutations?

dominant X-linked autosomal recessive

T/F: time between transfer of genes can be used as a measure of the "distance" of the genes between one another

true

UV light primarily produces thymine-thymine dimers while ______ and _______ causes double-stranded DNA breaks

IR gamma

16:11

Imbedded in the plasma membrane, Ras proteins act as molecular switches that transmit molecular signals from outside to inside the cell. Activated Ras proteins transduce a signal, which activates the transcription of genes that start cell division. Mutant Ras proteins are locked into the "on" position, continually signaling cell division.

What is catabolite repression? How does it allow a bacterial cell to use glucose in preference to other sugars?

In catabolite repression, the presence of glucose inhibits or represses the transcription of genes involved in the metabolism of other sugars. Because the gene expression necessary for utilizing other sugars is turned off, only enzymes involved in the metabolism of glucose will be synthesized. Operons that exhibit catabolite repression are under the positive control of catabolic activator protein (CAP). For CAP to be active, it must form a complex with cAMP. Glucose affects the level of cAMP. The levels of glucose and cAMP are inversely proportional—as glucose levels increase, the level of cAMP decreases. Thus, CAP is not activated.

19:4

In general, bacteria do not process eukaryotic proteins in the same manner as eukaryotes. Transgenic eukaryotes are more likely to correctly process eukaryotic proteins, thus increasing the likelihood of their normal biological activity

Describe how the Ames test screens for potential environmental mutagens. Why is it thought that a compound that tests positively in the Ames test may also be carcinogenic?

In the Ames assay, the compound to be tested is incubated with a mammalian liver extract to simulate an in vivo environment. This solution is then placed on culture plates with an indicator microorganism, Salmonella typhimurium, which is defective in its normal repair processes. The frequency of mutations in the tester strains is an indication of the mutagenicity of the compound. Because cancer results from the mutation of genes in somatic cells, mutagenic chemicals are considered to be potentially carcinogenic.

describe how acridine dyes cause frameshift mutations

Intercalation b/t bases of intact DNA causes DNA polymerase to add or skip a base during replication

Introns are known to contain termination codons (UAA, UGA, or UAG), yet these codons do not interrupt the coding of a particular protein. Why?

Introns are removed from mRNA before translation

what type of repair is this describing? allows joining of broken DNA chromosome homologous recombination defects in this pathway may reflect genetic disposition to breast and ovarian cancer

double stranded break repair (in mammals)

What is p53 and what is its significance?

It is a tumor suppressor gene that normally functions to control cell cycle transition including from late G1 to S and G2 to M. Mutations in the p53 gene are important in the development of a number of cancers. The product of p53 has DNA-binding properties.

one of the primary reasons for the necessity of generating a large number of clones in a eukaryotic genomic library is that

each vector can take up only a very small fraction of the eukaryotic DNA

Chapter 16: 5

Kinases regulate other proteins by adding phosphate groups. Cyclins bind to the kinases, switching them on and off. CDK4 binds to cyclin D, moving cells from G1 to S. At the G2/mitosis border a CDK1 (cyclin-dependent kinase) combines with another cyclin (cyclin B). Phosphorylation occurs, bringing about a series of changes in the nuclear membrane via caldesmon, cytoskeleton, and histone H1.

A lac operon produces the greatest amount of β-galactosidase when

Lactose present, glucose absent

During what genetic process are lampbrush chromosomes present in vertebrates?

Lampbrush chromosomes are typically present in vertebrate oocytes and are so named because their appearance is similar to brushes used to clean kerosene lamp chimneys in the nineteenth century. They are also found in spermatocytes of some insects. They are found as diplotene stage structures and are active uncoiled versions of condensed meiotic chromosomes. Lampbrush chromosomes are typically viewed using light and electron microscopy.

The A and P sites are progressively occupied by amino acids being assembled into a chain in protein synthesis. These sites are part of

Large ribosomal subunit

what is an example that professor chen used for codominance?

MN blood group (M and N are 2 alternative forms of the glycoprotein and an individual may express one or both)

18:4

Map-based cloning approach first organizes DNA clones of a genomic library into a physical map based on their chromosomal loci. It then subclones the large DNA clones into a library of small DNA fragments that can be sequenced. The shotgun approach forfeits the step of genome mapping and subcloning. It sequences directly the random small (~1.5 kb) fragments generated from the genome DNA before assembling those sequences into a whole-genome sequence with a computation algorithm.

_________ was a pioneer for genetics

Mendel (gregor)

18:15

Metagenomics is a relatively new discipline that examines the genomes from entire communities of microbes in environmental samples of water, air, and soil. Virtually every environment on Earth is being sampled in metagenomics projects. A major initiative is a global expedition called the Sorcerer II Global Ocean Sampling (GOS), in which researchers travel the globe by yacht and sample as many microbes as possible. Metagenomics is teaching us more about millions of species of microbes, of which only a few thousand have been well characterized. According to the text, "Metagenomics is providing important new information about genetic diversity in microbes that is key to understanding complex interactions between microbial communities and their environment, as well as allowing phylogenetic classification of newly identified microbes. Metagenomics also has great potential for identifying genes with novel functions, some of which have potentially valuable applications in medicine and biotechnology."

Cystic fibrosis (CF) is a severe autosomal recessive disorder in humans that results from a chloride ion channel defect in epithelial cells. More than 500 mutations have been identified in the 24 exons of the responsible gene (CFTR, or cystic fibrosis transmembrane regulator), including dozens of different missense mutations, frameshift mutations, and splice-site defects. Although all affected CF individuals demonstrate chronic obstructive lung disease, there is variation in whether or not they exhibit pancreatic enzyme insufficiency (PI). Speculate as to which types of mutations are likely to give rise to less severe symptoms of CF, including only minor PI. Some of the 300 sequence alterations that have been detected within the exon regions of the CFTR gene do not give rise to cystic fibrosis. Taking into account your knowledge of the genetic code, gene expression, protein function, and mutation, describe why this might be so.

Missense mutations usually change single amino acids in a protein while the frame shift or the splice-site mutation would likely cause multiple amino acid change. Therefore, missense mutations likely lead to less deleterious defect in the carriers than either the frame shift or the splice-site mutations. Of the mutations that don't lead to any CF symptoms, there are at least two possibilities. First, the mutations could introduce silent mutations that would not change the primary sequence of the ion channel. Second, the mutations may also introduce neutral mutations that don't substantially reduce the function of the protein. For example, when a hydrophobic residue in the ion channel is replaced by another one hydrophobic amino acid through a mutation, this will unlikely lead to deleterious effect on the protein function.

mutations may exert a variety of effects on living systems. list at least three categories of mutations based on their biological effects.

Morphological, nutritional or biochemical and behavioral mutations.

16:14

Mutations that produce oncogenes alter gene expression either directly or indirectly and act in a dominant capacity. Proto-oncogenes are those that normally function to promote or maintain cell division. In the mutant state (oncogenes), they induce or maintain uncontrolled cell division; that is, there is a gain of function. Generally, this gain of function takes the form of increased or abnormally continuous gene output. On the other hand, loss of function is generally attributed to mutations in tumor-suppressor genes, which function to halt passage through the cell cycle. When such genes are mutant, they have lost their capacity to halt the cell cycle. Such mutations are generally recessive.

incomplete dominance

Neither allele is dominant, so phenotypic ratio is identical to genotypic ratio. Pink Flowers.

the one-gene:one enzyme hypothesis from work on which two organisms

Neurospora and humans

16:18

Normal cells are often capable of withstanding mutational assault because they have checkpoints and DNA repair mechanisms in place. When such mechanisms fail, cancer may be a result. Through mutation, such protective mechanisms are compromised in cancer cells, and as a result they show higher than normal rates of mutation, chromosomal abnormalities, and genomic instability.

Why were 32P and 35S chosen in the Hershey-Chase experiment? Discuss the rationale and conclusions of this experiment.

Nucleic acids contain large amounts of phosphorus and no sulfur, whereas proteins contain sulfur and no phosphorus. Therefore, the radioisotopes 32P and 35S will selectively label nucleic acids and proteins, respectively. The Hershey and Chase experiment is based on the premise that the substance injected into the bacterium is the substance responsible for producing the progeny phages and therefore must be the hereditary material. The experiment demonstrated that most of the 32P-labeled material (DNA) was injected while the phage ghosts (protein coats) remained outside the bacterium. Therefore, the nucleic acid must be the genetic material.

What are the molecular composition and arrangement of the components in the nucleosome?

Nucleosomes are octomeric structures of two molecules of each histone (H2A, H2B, H3, and H4) except H1. On the surface of the nucleosomes and complexed with linker DNA is histone H1. A 146-base-pair sequence of DNA wraps around the nucleosome.

Epistasis

Occurs when the expression of one gene or gene pair masks or modifies the expression of another gene or gene pair.

RNAi (RNA interference) is a form of gene expression regulation in which double-stranded RNA molecules act, through various intermediates, to degrade mRNAs. What are the commonly used sources of variation applied to human DNA profiling?

Often variations in DNA can be revealed by restriction endonucleases to generate restriction fragment-length polymorphisms (RFLPs). In addition, VNTRs, SNPs, and STRs provide individual variation suitable for DNA profiling.

Define and indicate the significance of (a) Okazaki fragments, (b) DNA ligase, and (c) primer RNA during DNA replication.

Okazaki fragments are relatively short DNA fragments (1000 to 2000 bases in prokaryotes) that are synthesized in a discontinuous fashion on the lagging strand during DNA replication. Such fragments appear to be necessary because template DNA is not available for 5'>3' synthesis until some degree of continuous DNA synthesis occurs on the leading strand in the direction of the replication fork. The isolation of such fragments provides support for the scheme of replication shown in the text. DNA ligase is required to form phosphodiester linkages in gaps that are generated when DNA polymerase I removes RNA primer and meets newly synthesized DNA ahead of it. Notice in the text that the discontinuous DNA strands are ligated together into a single continuous strand. Primer RNA is formed by RNA primase to serve as an initiation point for the production of DNA strands on a DNA template. None of the DNA polymerases are capable of initiating synthesis without a free 3' hydroxyl group. The primer RNA provides that group and thus can be used by DNA polymerase III.

16:13

Oncogenes are genes that induce or maintain uncontrolled cellular proliferation associated with cancer. They are mutant forms of proto-oncogenes, which normally function to regulate cell division. Oncogenes may be formed through point mutations, gene amplification, translocations, repositioning of regulatory sequences, or other mechanisms.

How many base pairs are in a molecule of phage T2 DNA that is 52 mm long?

One base pair occupies 0.34 nm; therefore, the equation would be as follows: 52 micro m/(0.34 nm/bp) X 1000 nm/mm = 152,941 base pairs

Recessive lethal allele

One wild-type copy is enough for the organism to survive, but two copies of the mutant allele is lethal.

Which term refers to a contiguous genetic complex that is under coordinated control?

Operon

photoactivation repair in E. coli: a thymidine dimer is cleaved by _____ PRE is only active in blue light in the visible spectrum

PRE

photoreactivation repair: reversal of UV damage: damaged DNA repaired by photoreactivation repair first form of DNA repair to be described but is not a primary mechanism for repairing damaged DNA _____ is activated by light in the blue range, associates with dimer in dark must absorb a photon of light to be activated, the bond creating the thymine dimmer is ________ by the PRE reverses the effect of the UV radiation

PRE cleaved

True or false: A retrovirus uses reverse transcriptase to make a DNA copy of RNA.

True

17:8

Plasmids were the first to be used as cloning vectors, and they are still routinely used to clone relatively small fragments of DNA. Because of their small size, they are relatively easy to separate from the host bacterial chromosome, and they have relatively few restriction sites. They can be engineered fairly easily (i.e., polylinkers and reporter genes added). For cloning larger pieces of DNA such as entire eukaryotic genes, cosmids are often used. For instance, when modifications are made in the bacterial virus lambda (λ), relatively large inserts of about 20 kb can cloned. This is an important advantage when one needs to clone a large gene or generate a genomic library from a eukaryote. In addition, some cosmids will only accept inserts of a limited size, which means that small, perhaps less meaningful fragments will be cloned unnecessarily. Both plasmids and cosmids suffer from the limitation that they can only use bacteria as hosts. YACs (yeast artificial chromosomes) contain telomeres, an origin of replication, and a centromere and are extensively used to clone DNA in yeast. With selectable markers (TRP1 and URA3) and a cluster of restriction sites, DNA inserts ranging from 100 kb to 1000 kb can be cloned and inserted into yeast. Since yeast, being eukaryotes, undergo many of the typical RNA and protein processing steps of other, more complex eukaryotes, the advantages are numerous when working with eukaryotic genes.

List three general categories of genetic changes that lead to the formation of oncogenes.

Point mutations, translocations, overexpression

Describe how giant polytene chromosomes are formed.

Polytene chromosomes are formed from numerous DNA replications, pairing of homologs, and absence of strand separation or cytoplasmic division. Each chromosome contains about 1000-5000 DNA strands in parallel register. They appear in specific tissues, such as salivary glands, of many dipterans like Drosophila. They appear as comparatively long, wide fibers with sharp light and dark sections (bands) along their length. Such bands (chromomeres) are useful in chromosome identification and detection of chromosomal rearrangements.

Enhancers have several structural and functional characteristics that distinguish them from promoters. Describe three such characteristics, focusing on how these traits differ between enhancers and promoters

Position need not be fixed. Orientation may be inverted without significant effect. They can act at a great distance from the promoter

Discuss the reasons why proteins were generally favored over DNA as the genetic material before 1940. What was the role of the tetranucleotide hypothesis in this controversy?

Prior to 1940, most of the interest in genetics centered on the transmission of similarity and variation from parents to offspring (transmission genetics). While some experiments examined the possible nature of the hereditary material, abundant knowledge of the structural and enzymatic properties of proteins generated a bias that worked to favor proteins as the hereditary substance. In addition, proteins were composed of as many as 20 different subunits (amino acids), thereby providing ample structural and functional variation for the multiple tasks that must be accomplished by the genetic material. The tetranucleotide hypothesis (about DNA structure) provided insufficient variability to account for the diverse roles of the genetic material.

Describe the functionof promoters in eukaryotes. Where are they usually located, relative to the corresponding gene (give a quantitative answer in base-pairs)? What two sequence elements do they normally possess?

Promoter regions are necessary for the initiation of transcription. Promoters that interact with RNA Pol II are usually located within 100 bp upstream of a gene and usually contain a TATA box (25-30) and a CAAT box (70-80)

What are the basic regulatory elements in a strand of DNA that allow for genes to be regulated? Are these different in eukaryotes and prokaryotes? If so, how?

Promoters, operators in prokaryotes. Promoters, proximal promoter elements, enhancers, and silencers in eukaryotes. Eukaryotic transcription is different in a few ways, most notably in that prokaryotic genes are transcribed as operons, while eukaryotic genes are not. In addition, the role of the nucleosome is different in eukaryotic transcription

16:25

Proteases in general and serine proteases specifically are considered tumor-promoting agents because they degrade proteins, especially those in the extracellular matrix. When such proteolysis occurs, cellular invasion and metastasis are encouraged. Consistent with this observation are numerous observations that metastatic tumor cells are associated with higher than normal amounts of protease expression. Inhibitors of serine proteases are often tested for their anticancer efficacy.

Describe two classes of proteins known to be involved in the regulation of the cell cycle.

Protein kinases selectively phosphorylate target proteins. When complexed with cyclins, critical points of the cell cycle are controlled.

What genetic process is occurring in a puff of a polytene chromosome?

Puffs represent active genes as evidenced by staining and uptake of labeled RNA precursors as assayed by autoradiography.

__________ __________ contain one or more resistance factors such as antibiotic resistance genes, they are very important in hospitals however, they become a big problem with they carry multiple drug resistances

R plasmids

comb shape in chicken represents one of the classic example of gene interaction. two gene pairs interact to influence the shape of the comb. the genes for rose comb (R) and pea comb (P) together produce walnut comb. the fully homozygous recessive condition (rrpp) produces the single comb. assume that a rose comb chicken is crossed with a walnut comb chicken and the following offspring are produced 17 walnut, 16 rose, 7 pea, and 6 single -give the genotypes of each of the offspring classes

R-Pp walnut R-pp rose rrPp pea rrpp single

two major components of the tobacco mosaic virus

RNA and protein

16:21

Radiotherapy is often administered externally or internally to damage the cell-cycle machinery, thus shrinking the cancer or killing cells of the cancer. It may be completely or partially effective. Because cells have natural defenses against mutagenic insult, drugs that increase a cell's sensitivity to radiation may be administered. Radiosensitizers and radioprotectors are chemicals that alter a cell's response to radiotherapy. Radiosensitizers make cells more sensitive to therapy, whereas radioprotectors are drugs that protect normal cells from the damage caused by radiation therapy. Radiotherapy kills cells; therefore, side effects are expected.

Expressivity

Range of expression of a gene.

17:3

Recombinant DNA technology, also called genetic engineering or gene splicing, involves the creation of associations of DNA that are not typically found in nature. Particular enzymes called restriction endonucleases cut DNA at specific sites and often yield "sticky" ends for additional interaction with DNA molecules cut with the same class of enzyme. Isolated from bacteria, restriction enzymes fall into several classes, each having peculiarities as to structure and interaction with DNA. A vector may be a plasmid, bacteriophage, or cosmid that receives, through ligation, a piece or pieces of foreign DNA. The recombinant vector can transform (or transfect) a host cell (bacterium, yeast cell, etc.) and be amplified in number.

You are designing a strategy to express a human protein in E.coli. You identified the nucleotide sequence of the corresponding human gene. The coding sequence is unusually large at 45,000 base pairs, almost impossible to clone into a bacterial plasmid. Which of the following strategies will likely reduce the length of this gene without compromising its function?

Remove the introns

16:23

Since there are multiple routes that lead to cancer, one would expect complex regulatory systems to be involved. More specifically, while in some cases, downregulation of a gene, such as an oncogene, may be a reasonable cancer therapy, downregulation of a tumor-suppressor gene would be undesirable in therapy. Various levels of methylation (hypermethylation and hypomethylation) influence gene activity and, therefore, can cause cancer.

Rrpp x RrPp

repetitive transposed sequences are short and long interspersed elements (SINES and LINES) __________ less than 500 bp, but about 50,000 in human genome __________ about 6,400 bp and ~100,000 copies __________ are likely derived from ancient retroviruses and make up a large portion of the human genome

SINES LINES retrotransposons

what type of repair is this describing? error prone because conditions are created that allow insertion of nucleotides despite incorrect base pairing

SOS repair (only in E. coli)

Independent Assortment

Segregation of any pair of unit factors occurs independently of all others.

What makes a good model organism?

Self fertilizing, but can cross breed. Reproduces quickly and grows well. Several different contrasting traits that can be easily followed from one generation to the next.

19:10

Since both mutations occur in the CF gene, children who possess both alleles will suffer from CF. With both parents heterozygous, each child born will have a 25 percent chance of developing CF.

What is the specific application of reverse transcriptase in the preparation of cDNA?

Synthesis of DNA from a single-stranded RNA template to form an RNA-DNA duplex

In the discovery of genetic codes, the scientists used polynucleotide phosphorylase to ___

Synthesize RNA

Two modular elements that appear as consensus sequences upstream from RNA polymerase II transcription start sites are

TATA and CAAT

in the initiation of eukaryotic gene transcription, TBP is essential in binding ___ for the assembly of PIC

TATA box

Alternative RNA processing can result in different mRNAs that start with different exons.

TRUE

Alternative RNA processing generates different mRNAs, which can direct the synthesis of different polypeptides.

TRUE

An upstream activator sequence (UAS) can function at variable distances and in either orientation. However, it differs from an enhancer in that it cannot function downstream of the transcription starting point.

TRUE

In general, one could say that fewer levels of regulation are possible in prokaryotes than in eukaryotes.

TRUE

The CAAT (CAAT box) sequence appears to be critical to the ability of many eukaryotic promoters to facilitate transcription.

TRUE

The term spliceopathy is often used to signify a genetic condition caused by a defect in the regulation of RNA splicing.

TRUE

Transcription factors are proteins with at least two functional domains-one that binds to DNA and one that binds to RNA polymerase or to other transcription factors

TRUE

18:8

The National Center for Biotechnology Information (NCBI) provides access to BLAST (Basic Local Alignment Search Tool) software that directs searches through databanks of DNA and protein sequences. A segment of DNA can be compared to sequences in major databases such as GenBank to identify matches that align in whole or in part. One might seek similarities to a sequence on chromosome 11 in a mouse and find that or similar sequences in a number of taxa. BLAST will compute a similarity score or identity value to indicate the degree to which two sequences are similar. BLAST is one of many sequence alignment algorithms (RNA-RNA, protein-protein, etc.) that may sacrifice sensitivity for speed.

True or false: In Drosophila, maternal effect genes are influential in determining the anterior-posterior organization of the developing embryo.

True

T/F: C-1' is always bonded to the nitrogenous base in nucleotides

true

What observations are consistent with the conclusion that DNA serves as the genetic material in eukaryotes? List and discuss them.

The early evidence would be considered indirect in that at no time was there an experiment, like transformation in bacteria, in which genetic information in one organism was transferred to another using DNA. Rather, by comparing DNA content in various cell types (sperm and somatic cells) and observing that the action and absorption spectra of ultraviolet light were correlated, DNA was considered to be the genetic material. This suggestion was supported by the fact that DNA was shown to be the genetic material in bacteria and some phage. Direct evidence for DNA being the genetic material comes from a variety of observations, including gene transfer that has been facilitated by recombinant DNA techniques.

Intron frequency varies considerably among eukaryotes. Provide a general comparison of intron frequencies in yeast and humans. What about intron size?

The entire yeast genome has only about 240 introns, whereas some single genes in humans contain over 100 introns. In general, smaller genomes have smaller intron size in addition to lower intron number.

Describe the various characteristics of the Watson-Crick double helix model for DNA.

The following are characteristics of the Watson-Crick double-helix model for DNA: The base composition is such that A=T, G = C and (A + G) = (C + T). Bases are stacked, 0.34 nm (3.4 Angstroms) apart, in a plectonic, antiparallel manner. There is one complete turn for each 3.4 nm, which constitutes 10 bases per turn. Hydrogen bonds hold the two polynucleotide chains together, each being formed by phosphodiester linkages between the five-carbon sugars and the phosphates. There are two hydrogen bonds forming the A to T pair and three forming the G to C pair. The double helix exists as a twisted structure, approximately 20 Angstroms in diameter, with a topography of major and minor grooves. The hydrophobic bases are located in the center of the molecule, while the hydrophilic phosphodiester backbone is on the outside.

What is the map distance between two genes?

The frequency of recombination between them.

T/F: DNA Pol 1 functions to remove the RNA primer and replace it with DNA

true

Which characteristics of DNA polymerase I raised doubts that its in vivo function is the synthesis of DNA leading to complete replication?

The in vitro rate of DNA synthesis using DNA polymerase I is slow, being more effective at replicating single-stranded DNA than double-stranded DNA. In addition, it is capable of degrading as well as synthesizing DNA. Such degradation suggested that it functioned as a repair enzyme. In addition, DeLucia and Cairns discovered a strain of E. coli (polA1) that still replicated its DNA but was deficient in DNA polymerase I activity.

What are the requirements for in vitro synthesis of DNA under the direction of DNA polymerase I?

The in vitro replication requires a DNA template, a primer to give a double-stranded portion, a divalent cation (Mg2+), and all four of the deoxyribonucleoside triphosphates: dATP, dCTP, dTTP, and dGTP. The lowercase "d" refers to the deoxyribose sugar.

It has been recently determined that the gene for Duchenne muscular dystrophy (DMD) is over 2000 kb (kilobases) in length; however, the mRNA produced by this gene is only about 17 kb long. What is a likely cause of this discrepancy?

The introns have been spliced out during mRNA processing

Explain why mutations in the lacI gene are trans in their effects, but mutations in the lacO gene are cis in their effects.

The lacI gene encodes the lac repressor protein, which can diffuse within the cell and attach to any operator. It can therefore affect the expression of genes on the same or different molecules of DNA. The lacO gene encodes the operator. It affects the binding of DNA polymerase (OR the lacI repressor) to the DNA, and therefore affects only the expression of genes on the same molecule of DNA.

16:10

The nonphosphorylated form of pRB binds to transcription factors such as E2F, causing inactivation and suppression of the cell cycle. Phosphorylation of pRB activates the cell cycle by releasing transcription factors (E2F) to advance the cell cycle. With the phosphorylation site inactivated in the PSM-RB form, phosphorylation cannot occur, thereby leaving the cell cycle in a suppressed state.

Phenotype

The physical appearance of a trait.

What was the significance of the polA1 mutation?

The polAI mutation was instrumental in demonstrating that DNA polymerase I activity was not necessary for the in vivo replication of the E. coli chromosome. Such an observation opened the door for the discovery of other enzymes involved in DNA replication.

True or false: The Human Genome Project is an international effort to determine the sequence of the 3.3 billion base pairs in the haploid human genome.

True

t/f a missense mutation causes premature chain termination

false

What two factors contribute significantly to the wide ranges of genome size among eukaryotes?

The presence of introns and repetitive sequences is a major contributor, as are the differences in the number of genes.

Describe the cellular and molecular function of the ras gene family and the consequences of mutations in ras.

The ras gene family encodes a protein of 189 amino acids, which is involved with signal transduction in the cell membrane. Point mutations may cause changes in function that promote abnormal signaling, thus stimulating uncontrolled cell growth.

True or false: To generate glyphosate resistance in crop plants, a fusion gene was created that introduced a viral promoter to control the EPSP synthetase gene.

True

True or false: Typically, bacterial DNA contains less repetitive DNA than eukaryotic DNA.

True

Chapter 16: 6

The retinoblastoma gene (RB1), located on chromosome 13, encodes a protein designated pRB. Cells progress through the G1/S transition when pRB is phosphorylated and CDK4 binds to cyclin D. In the absence of phosphorylation of pRB, it binds to members of the E2F family of transcription factors, which controls the expression of genes required to move the cell from G1 to S. When E2F and other regulators are released by pRB, they are free to induce the expression of over 30 genes whose products are required for the transition from G1 into S phase. After cells traverse S, G2, and M phases, pRB reverts to a nonphosphorylated state, binds to regulatory proteins such as E2F, and keeps them sequestered until required for the next cell cycle.

Draw the chemical structure of the three components of a nucleotide, and then link them together. What atoms are removed from the structures when the linkages are formed?

The structure of deoxyadenylic acid is given below and in the text. Linkages among the three components require the removal of water (H2O)

What role does RNA stability play in gene reguation? List three types of RNA structural elements that can affect the stability of an RNA molecule in eukaryotic cells. Explain how these elements act to influence RNA stability.

The total amount of protein synthesized is dependent on how much mRNA is available for translation. The amount of mRNA present is dependent on the rates of mRNA synthesis and degradation. Less stable mRNAs will be degraded and become unavailable as templates for translation. The presence of the 5' cap, 3' poly A tail, the 5' UTR, 3' UTR, and the coding region in the mRNA molecule affects stability. Poly A binding proteins bind at the 3' tail and contribute to stability and protect the 5' cap through direct interaction. Once a critical number of adenine nucleotides have been removed from the tail, the protection is lose and the 5' cap is removed. the 5' cap removal always for the 5' to 3' nucleasees to degrade the mRNA.

Describe three separate genetic mechanisms whereby proto-oncogenes can become overexpressed.

They may acquire a new promoter or upstream regulatory signals, additional copies (amplification), or a change to more transcription active chromatin structure.

17:6

This segment contains the palindromic sequence of GGATCC, which is recognized by the restriction enzyme BamHI. The double-stranded sequence is the following: CCTAGG GGATCC

List three main differences between DNA and RNA.

Three main differences between RNA and DNA are the following: (1) uracil in RNA replaces thymine in DNA, (2) ribose in RNA replaces deoxyribose in DNA, and (3) RNA often occurs as both single- and partially double-stranded forms, whereas DNA most often occurs in a double-stranded form.

When Avery and his colleagues had obtained what was concluded to be the transforming factor from the IIIS virulent cells, they treated the fraction with proteases, ribonuclease, and deoxyribonuclease, followed by the assay for retention or loss of transforming ability. What were the purpose and results of these experiments? What conclusions were drawn?

Transformation is dependent on a macromolecule (DNA) that can be extracted and purified from bacteria. During such purification, however, other macromolecular species may contaminate the DNA. Specific degradative enzymes, proteases, RNase, and DNase were used to selectively eliminate components of the extract and, if transformation is concomitantly eliminated, then the eliminated fraction is the transforming principle. DNase eliminates DNA and transformation; therefore, it must be the transforming principle.

Alternative RNA processing can result in different mRNAs that consist of different exons.

True

In the eukaryotic promoters that have it, the CAAT box appears to be critical to the promoter's ability to facilitate transcription.

True

Poly-A tail increases the stability of mRNA in eukaryotes.

True

True or false: A restriction map provides the location of sites cleaved by restriction enzymes.

True

t/f acridine orange is a alkylating agent

false

Monod discovered that if tryptophan is present in relatively high quantities in the growth medium, the enzymes necessary for its synthesis are repressed. How does this occur?

Tryptophan acts as a corepressor to activate the tryptophan repressor protein; it is also involved in an attenuation system, which causes the termination of transcription.

What is the difference between tumor suppressor genes and proto-oncogenes?

Tumor suppressor genes act to restrict cell division, while proto-oncogenes act to stimulate cell division

Transduction mapping

Used to determine gene order.

Test Cross

Used to determine the genotype of an individual that expresses a dominant trait.

19:12

Using restriction enzyme analysis to detect point mutations in humans is a tedious trial-and-error process. Given the size of the human genome in terms of base sequences and the relatively low number of unique restriction enzymes, the likelihood of matching a specific point mutation, separate from other normal sequence variations, to a desired gene is low.

After transformation of a human gene into E.coli, you found out that the human protein is lethal to the host E.coli cells if it is constantly expressed. Which modification will likely enable conditional production of this protein?

Utilize the cis-elements of the lactose operon to express this gene

DNA fingerprinting often makes use of VNTRs. Why?

VNTRs (variable number tandem repeats) are highly variable portions of eukaryotic chromosomes. They are sufficiently variable as to be unique to each individual.

DNA fingerprinting often makes use of VNTRs, why

VNTRs are highly variable portions of eukaryotic chromosomes. they are sufficiently variable as to be unique to each individual

Describe a tautomeric shift and how it may lead to a mutation.

Watson and Crick recognized that various tautomeric forms, caused by single proton shifts, could exist for the nitrogenous bases of DNA. Such shifts could result in mutations by allowing hydrogen bonding of normally noncomplementary bases so that incorrect nucleotide bases may be added during DNA replication. As stated in the text, important tautomers involve keto-enol pairs for thymine and guanine and amino-imino pairs for cytosine and adenine.

Product Law of Probabilities

When two independent events occur simultaneously, the combined probability of the two outcomes is equal to the product of their individual probabilities of occurrence.

Multiple Alleles

Where there are more than two alleles of a single locus that produce fully functional but distinct products. This is in contrast to Mendel's hypothesis: Alleles are always in pairs.

Regarding the tryptophan operon, trpR- maps a considerable distance from the structural genes. The mutation either inhibits the interaction with tryptophan or inhibits repressor formation entirely. In the presence of tryptophan in the medium, would you expect the tryptophan operon to be transcriptionally active in this mutant? Explain.

With either of the two scenarios mentioned in the problem, absence of repressor function in a repressible system means that there would be no repression of the operon. The operon would be transcriptionally active

Why are X rays more potent mutagens than UV radiation?

X rays are of higher energy and shorter wavelength than UV light. They have greater penetrating ability and can create more disruption of DNA.

______ genes counteract DNA damage in normal cells recognition of the damaged DNA by proteins encoded by XPC, XPE, and XPA genes these proteins recruit other repair proteins to the damage site the XPB and XPD genes encode ________ the XPF and XPG genes encode _________ excision repair complex moves 28 nt long fragment that contains the lesion, gap in lesion filled using complementary strand sequence and ligase

XP helicases nucleases

What are zinc fingers, and why are they frequently encountered in descriptions of genetic regulation in eukaryotes?

Zinc fingers consist of amino acid sequences containing two cysteine and two histidine residues at repeating intervals. Interspersed cysteine and histidine residues covalently bind zinc atoms, folding the amino acids into loops (zinc fingers). They are one of the major groups of eukaryotic transcription factors. They were originally discovered in the Xenopus transcription factor TFIIA, and this structural motif has been identified in a variety of significant regulatory circumstances, including proto-oncogenes and developmental control genes in Drosophila.

t/f avery determined that DNA is the genetic material in the bacteriophage

false

To express a human gene in E.coli, you will attach ______ to this human gene in the plasmid before its transformation into bacteria.

a bacterial promoter

Conditional mutations are more likely to result from which of the following alterations to the coding region of a gene. -a mutation caused by a base addition or deletion - a mutation caused by a base addition - a mutation caused by X rays - a mutation caused by a deletion - a mutation caused by a tautomeric shift

a mutation caused by a tautomeric shift

secondary structure of a protein includes the following features

a-helix and B-pleated sheet

what is this definition? involves loss of either guanine or adenine from a base of the DNA

apurinic sites

Assuming one mutational event in a gene, on average, which of the following mutagens would be expected to cause the most damage to a protein synthesized by such a mutagenized gene? - 5-bromouracil - 2-aminopurine - acridine orange - ethylmethane sulfonate

acridine orange

conversion of guanine to 6-ethylguanine by the alkylating agent ethylmethane sulfonate (EMS) results in altered base pairing ___________ the 6-ethylguanine base pairs with _______

affinities thymine

what is an example that professor chen gave us for recessive lethal alleles?

agouti gene (hair color in mice)

what are other examples besides the bombay phenotype that would be a result of epistasis?

albinism hair color and baldness

many human genetic diseases are the result of mutations in enzymes in nutritional and /or biochemical pathways what disease/syndrome is this? enzyme converts tyrosine to DOPA, form which melanin is derived

albinism (tyrosinase gene)

___________ __________ proposed that recombinations frequencies could be used to map the sequence (order) of linked genes on the chromosome sum of 1 and 2 approximately equals 3 which suggested the recombination frequencies between genes are additive 1 map unit = _____% recombination

alfred sturtevant 1

what did the enzyme that could direct DNA synthesis in a cell free system require?

all four dNTPs (dATP, dCTP, dGTP, dTTP) DNA template

Three human disorders-fragile X syndrome, myotonic dystrophy, and Huntington disease-are conceptually linked by a common mode of molecular upset. Describe the phenomena that link these disorders.

all of these are caused by disparate genes, but each gene was found to contain repeats of a unique trinucleotide sequence. in addition, the number of repeats may increasse in each subsequent generation

what is this definition? alternative forms of a gene, but are the same gene

alleles

in human chromosomes, there are satellite DNA sequences of about 170 bp in length that are present in tandem arrays of up to 1 million bp. found mainly in centromere regions, they are called

alphoid families

when thymine is in enol form it can base pair with guanine instead of adenine when cytosine is in imino form it pairs with adenine instead of guanine purine-pyrimidine base pairing is ___________ maintained in these cases

always

In what part of the mRNA does degradation generally begin? - at the 5' end with the removal of the polyA tail - at the 5' end with the removal of the methyl cap - at the 3' end with the removal of the polyA tail - at the 3' end with the removal of the methyl cap - removal from either end is equally likely

at the 3' end with the removal of the polyA tail

what form of transposon is this? can transpose by themselves mutations created by insertion of these elements into a gene are unstable because they can excise and move to a new location frequency of transition out of a gene is higher than the spontaneous reversion frequency of a point mutation

autonomous

what are the two forms of transposons?

autonomous nonautonomous

what are the two forms of transposons?

autonomous nonautonomous

what form of transposons is this describing? can transpose by themselves mutations created by insertion of these elements into a gene are unstable because they can excise and move to a new location frequency of transposition out of a gene is higher than the spontaneous reversion frequency of a point mutation

autonomous elements

what are yeast origins called?

autonomously replicating sequences (ARSs)

what type of gametic mutation is this? not expressed in heterozygotes, requires two heterozygotes to mate, bringing together two copies of the mutant allele in the homozygous recessive condition

autosomal

what type of phenotype is this in bacteria? have a mutation that results in the loss of ability to make at least one essential organic component - loss of ability to make His, amino acid must be added to minimal medium for growth

auxotrophs

how does an auxotroph differ from a prototroph

auxotrophs have lost, through mutation, the ability to grow on minimal medium

Transduction

bacterial recombination mediated by bacteriophage.

basic structure of a nucleotide includes

base, sugar and phosphate

what are minisatellites and microsatellites

both are highly repetitive, relatively short DNA sequences. microsatellites have a shorter repeat length than do minisatellites

(E. coli is the example for this as shown in the notes) what direction to the replication forks migrate in E. coli DNA replication?

both directions away from the origin

how are phenotypes determined?

by which alleles of a gene are present in an organism

what scientific activities do the terms synkaryon and heterokyran refer

cell (heterokaryon) and nuclear (synkaryon) fusion and gene mapping in eukaryotes

what is meant by punctuation in terms of the genetic code

certain triplet (AUG) commonly signals the starting point for protein synthesis, while other triplets signal stop (UAA, UGA, UAG)

what were the two studies done to show DNA acts as the genetic material?

chargaffs frankling and wilkin

what was the source of gene separation from morgan's crossing with X linked genes?

chiasmata (during meiosis the synapsed chromosomes wrap around each other creating points of overlap) (morgan proposed these are points of genetic exchange)

what do alkylating agents do?

donate an alkyl group to amino or keto groups in nucleotides

what type of cell is this in bacterial conjugation? provides genetic material (DNA)

donor cells (F+)

eukaryotic DNA organization: chromosomes visible only during mitosis or meiosis, after cell division cells enter interphase, components of the chromosome uncoil and disperse in the nucleus ____________ organization of DNA during transitions is intricate and complex compared to bacteria and viruses compared to prokaryotes, there are more proteins associated with eukaryotic DNA, positively charged ________, contain large amounts of positively charged amino acids, like lys, arg to bond electrostatically to the negative charged phosphate groups of _____________

chromatin histones nucleotides

to accommodate protein-DNA interactions, chromatid is induced to change its structure by a process called ___________ _________

chromatin remodeling

proteins that affect chromatin structure without altering histone chemical structure are called ________

chromatin remodeling structures

bacterial operon

contains information for more than one protein product

synthesis occur simultaneously on both strands: as strands unwind and replication fork moves down the helix, only one strand can serve as a template for ________ DNA synthesis, newly synthesized strand is the ______ strand as the fork progresses, many points of initiation are needed on the opposite DNA strand, resulting in __________ DNA synthesis of the __________ strand which results in production of ___________ fragments

continuous leading discontinuous lagging okazaki

what type of transduction is this by bacteriophage? genes that are closely linked on the bacterial chromosome can be simultaneously transduced

cotransduction

what is it meant by the term cotransformation

cotransformation occurs when several linked genes are transformed simultaneously

for humans the foremost concern is in the potential to __________ the genetic damage that results in cancer

counteract

Aminoacyl-tRNA synthetase attaches an amino acid ____ of the tRNA

covalently to 3'

size of chloroplast DNA is much greater than mitochondrial DNA. what accounts for the difference in size

cpDNA has many noncoding sequences, both within and between genes. in addition, cpDNA contains a larger number of genes

X-linked trait that is homozygous recessive will be passed on from mother to all sons -> _______ __________ pattern of inheritance

criss-cross

kornberg and colleagues found that DNA synthesis was inhibited if: any ________ was omitted or if other forms of nucleotides were used DNA template was not added

dNTP

what primary ingredients, coupled with DNAP I, are needed for the in vitro synthesis of DNA

dNTP, DNA template, primer DNA or RNA, Mg2+

what type of cross is this? a two-factor cross that simultaneously examines two pairs of contrasting traits

dihybrid

intron frequency varies considerably among eukaryotes. provide a general comparison of intron frequencies in yeast and humans. what about intron size?

entire yeast genome has only about 240 introns, whereas some single genes in humans contain over 100 introns. in general, smaller genomes have smaller intron size in addition to lower intron number

condition in which one gene pair masks the expression of a nonallelic gene pair is called

epistasis

what is this definition? occurs when the expression of one gene or gene pair masks or modifies the expression of another gene or gene pair

epistasis

short tandem repeats (STRs) are very similar to VNTRs but the motif is shorter (two to nine bp). the FBI and other law enforcement agencies couple PCR with STR analyses to

establish databases against which suspects can be screened

Parts of chromosomes that are not methylated for inactivation, but rather are less dense-staining and are likely active in transcription in the cell.

euchromatin

what is this describing? -decondensed during interphase -most actively expressed genes found in euchromatin -replicates earlier in S phase

euchromatin

regulation of gene expression using siRNAs is found in -prokaryotes only -eukaryotes only -both

eukaryotes only

what three things contributed to mendel's success?

excellent model organism quantitative approach hypothesis driven

what is DNA susceptible to?

exogenous/environmental agents endogenous by-products of normal cellular processes spontaneous or induced chemical processes

what characteristic of genetic material is this? must be expressed, the process of transcription and translation

expression of information

what is this definition? the range of expression of a gene

expressivity (ex. eyeless in Drosophila flies, graduations in phenotype range from wild type to partial reduction to eyeless)

T/F: excision repair is conserved only in eukaryotes it is a light-independent cut and past mechanism that repairs damage caused by exogenous and endogenous agents

false (conserved in both prokaryotes and eukaryotes)

T/F: one complete turn of the helix is 24 anstrom or 2.4 nm long

false (is 34 angstrom or 3.4 nm long)

is this true or false for recombination in F+ x F- matings? recipient bacterium will appear as a recombinant but will not remain F-

false (it WILL remain F-)

T/F: prokaryote DNA polymerases have a proofreading function called the 5' to 3' exonuclease activity

false (it is called the 3' to 5' exonuclease activity)

mutation in human genes: number of repeats in creases in each generation called _________ ________ sometimes mutation is in coding region other times in upstream or downstream region mechanism for expansion unknown

genetic anticipation

what is this definition? have a progressively earlier age of onset with each generation, display increased severity of the disorder in each successive generation

genetic anticipation

what are insertion sequence (IS) elements?

genetic elements that can move, transpose, within a genome they cause mutations in genes when they insert within a coding sequence or within a regulatory sequence they are caused by short DNA sequences inserted into the bacterial genome at the start of the galactose gene cluster

structure of the nucleosome core particle: histones are rich in arginine and lysine positive charges from these amino acids can neutralize the negative charge of the DNA backbone and results in __________ interactions that hold the DNA and protein together in the nucleosome

hydrophobic

mouse and human cells defective in BER activity are ___________ to the killing effects of gamma rays and oxidizing agents

hypersensitive

kornberg and colleagues purified an enzyme from E. coli that could direct DNA synthesis in an _____ _______ (cell-free) system

in vitro

what type of dominance is this? when one allele for a specific trait is not completely expressed over its paired allele that results in a third phenotype which is a combination of the other two allels

incomplete (partial) dominance

overview of structure of Z-DNA

left-handed helix with two antiparallel complementary strands, 1.8 nm in diameter, 12 bp per turn, zigzag configuration, and shallow major groove

what is this definition? segregation of any pair of unit factors occurs independently of all others

independent assortment

what are the two factors in mendel's fourth postulate?

independent assortment (results of) random segregation

what type of mutation is this? result from the influence of artificial factors (mutagens) chemical or physical damage

induced

A chemical X55 stimulates the methylation of DNA and can be easily taken up by dividing cells. Researchers are exploring the potential of X55 as a new anticancer drug because X55 likely ___

inhibits DNA transcription

______ and _______ can result in alteration of the reading frame downstream of the mutation

insertions deletions

Channels between chromosomes in the interphase nucleus are called - extrachromosomal elements - localized zones - nonlocalized zones - interchromosomal compartments - subchromosomal territories

interchromosomal compartments

genetic mapping in Hfr strains uses what technique?

interrupted mating technique

what is this definition? - certain genes were transferred before others - genes always transferred in a certain order correlated with the length of time conjugation proceeded

interrupted mating technique

what is an intron and what is the relationship between an intron and heterogenous nuclear RNA

intron is section of DNA, which when transcribed as a part of an RNA, is eventually spiced out of that RNA. entire initial gene transcript, which may serve as an eventual mRNA (after intron removal and other forms of processing) is called heterogenous nuclear RNA

mitochondrial DNA (mtDNA) similar to bacterial chromosomes: -dsDNA, closed circle, no ________ -varies in size from 16 kb (human), 75kb in yeast -encodes ribosomal RNAs, tRNAs and 13 proteins of the oxidative respiratory functions, majority of proteins that function in mitochondria are encoded by nuclear _________

introns genes

intros are known to contain termination codons (UAA, UGA, or UAG) yet these codons do not interrupt the coding of a particular protein. why

introns are remove from mRNA before translation

which of the following sets of two terms relate most closely to split genes

introns, exons

_________ - __________ experiment used a Davis U tube for this experiment and found that recombination between two strains of salmonella occur without the cells touching, a "filterable agent" as a cause, determined to be a phage

lederberg zinder

Describe alternative splicing. what is the result of this mechanism?

it is the differential splicing of alternative exons from an initial pre-mRNA transcript. The result is that the possible proteins that a cell can produce is far larger than the number of genes in the genome.

a single crossover between two nonsister chromatids and the gametes subsequently produced: (A) the exchange does not alter the linkage arrangement between the alleles of the two genes, only parental gametes form and the exchange goes undetected OR (B)the exchange separates the alleles and results in recombinant gametes, which are detectable

it produced both

who proposed a double helix structure of DNA which revealed a structure with required properties of genetic material?

james watson and francis crick (1953)

deamination of cytosine and adenine: amino group is converted to a ____ group deaminated cytosine becomes uracil which base pairs with _________ deaminated adenine become ___________ which base pairs with cytosine

keto adenine hypoxanthine

tautomeric forms are an alternative chemical form that differs by a single proton shift in the molecule thymine and guanine: normal form is ______ alternative form is enol cytosine and adenine: normal form is amino, alternative form is ________

keto imino

a constitutive mutation in the lac operon may be of several types. name two types of constitutive mutation

lacI- and lacOc

the lac repressor binds to: -lactose and DNA -RNA polymerase -RNA polymerease and DNA -d galactosidase, permease and tranacetylase -promoter and lactose

lactose and DNA

replication of telomeres: ________ strand synthesis cannot be completed at the telomere because the primer can not be ______ down (there is no template, the final gap is at the end of the fragment, no okazaki fragment to provide the needed 3'-OH)

lagging laid

what specialized eukaryotic chromosome is this? -characteristic of most vertebrate oocytes -chromosomes are synapsed but not condensed -represent regions of chromosomes that are expressed during meiosis -informative on organization of chromosomes because of their large size

lampbrush chromosomes

what is this definition? if a gene is not needed until later in life is mutated then the effects of that mutation will not manifest until the mutant gene is expressed

late-onset genetic disease

double crossover phenotypes exist in the ___________ population

least (least number of offspring)

__________ and __________ (1946) developed a hypothesis that bacteria undergo a "parasexual" process where genetic material from one bacterium is transferred to an recombined with that of another, also called _____________

lederberg tatum conjugation

many human genetic diseases are the result of mutations in enzymes in nutritional and /or biochemical pathways what disease/syndrome is this? defect in hypoxanthine-guanine phosphoryl-ribose transferase (HGPRT), essential for purine use

lesch-nyhan

when two genes fail to assort independently, the term normally applied is

linkage

assume that a cross is made between AaBb and aabb plants and that the offspring occur in the following numbers: 106 AaBb, 48 Aabb, 52 aaBb, 94 aabb. these results are consistent with

linkage with approximately 33 map units between the two gene loci

micrococcal nuclease digestion of chromatin: the nucleosome core particle is released from chromatin by digestion of the _________ DNA with micrococcal nuclease

linker

in general, what two methods are used to grow bacteria in the laboratory

liquid and semisolid (agar) media

assume that investigators crossed a strain of flies carrying the dominant eye mutation Lobe on the second chromosome with a strain homozygous for the second chromosome recessive mutations smooth abdomen and straw body. the F1 Lobe females were then backcrossed with homozygous smooth abdomen, straw body males and the following phenotypes: smooth abdomen, straw body 820 lobe 780 smooth abdomen, lobe 42 straw body 58 smooth abdomen 148 lobe, straw body 153 -give the gene order and map units between these loci

lobe is in the middle smooth abdomen-5-lobe-15-straw body

what type of transposon is this in humans? at least one instance where a new mutation caused was not present on X chromosome of either parent but was present on their 22nd chromosomes suggests transposon moved in germ line

long interspersed elements (LINES)

why did the frequency of the apparent separation vary depending on the genes being studied in morgan's X-linked genes?

morgan found that the distance between the genes determined the frequency of recombination between those two genes

what effect of mutation trait is this? how the organism appears

morphological

large subunits of ribosomes

mostly provide catalytic activity of extending polypeptide

chloroplast DNA (cpDNA) also similar to bacterial DNA: -120-200 kb, circular, double-stranded, free of associated proteins, larger than _______, has introns -some enzymes have ___ subunits one whose gene is in the nucleus and the other in the chloroplast

mtDNA 2

what type of allele is this? when there are more than two alleles of a single locus that produce fully functional but distinct products

multiple

what type of crossover is this? occur between the chromatids of a tetrad easier to determine gene order by studying crossovers that occur between three genes on a chromosome

multiple

DNA replication origins for eukaryotes: eukaryotes have ______ origins of replication rate of DNA replication is 2600 bp/min with one origin or replication it would take _____ weeks actual time is only ______ mins about __________ origins of replication (25,000 in mammals)

multiple 2 4 7000

a situation in which there are more than two alternative forms of a given gene is called

multiple alleles

what genetic material is this for eukaryotic cells? ultraviolet light is a powerful mutagen nucleic acids absorb UV light at 260 nm protein absorbs UV light at 280 nm and highest level of mutagenesis is observed at 260 nm

mutagenesis

what is this definition? process by which the sequence of base pairs in a DNA molecule is altered simple = single base substitutions, insertions, or deletions complex = chromosomal rearrangements, duplications, or deletions

mutation

what type of allele is this? have modified genetic material, may produce altered gene product like a protein

mutation

Auxotrophs

mutation results in loss of the ability to make at least one essential organic component - loss of ability to make His, amino acid must be added to minimal medium for growth. Do not grow on Minimal Medium, need supplements.

what disease/syndrome is this? CTG expansion in downstream region

myotonic dystrophy

high frequency recombination remains donors (F+) if the donor is from Hfr strain, recipient cells _______ become Hfr but remain ______

never F-

what are the three essential components of nucleotides?

nitrogenous base pentose sugar phosphate group

do linked genes undergo independent assortment?

the enzyme glucose-6-phosphate dehydrogenase deficiency (G6PD) is inherited as a recessive gene of the X chromosome in humans. a phenotypically normal woman (whose father had G6PD) is married to a normal man -if the husband had G6PD, would it make a difference to your answer in part a?

In a three-point mapping experiment, what three general classes of offspring are expected (assuming crossovers occur)?

non crossovers, single crossovers, double crossovers

what form of transposon is this? cannot transpose by themselves because they lack the gene needed for transposition require the presence of an autonomous element to supply the missing functions usually a deletion mutant insertions are stable (with exceptions)

nonautonomous

what form of transposons is this describing? cannot transpose by themselves because they lack the gene needed for transposition require the presence of an autonomous element to supply the missing functions usually a deletion mutant of an autonomous element insertions are stable, unless an autonomous element is also present

nonautonomous elements

e.coli bacteria are placed into a medirum containing glucose and lactose. which of the genes below do you expect to be turned on? -f-galactosidase -Lac I -Lac P -Permease -none of the above

none of the above

A _________ mutation changes a codon that specifies an amino acid into one that terminates translation - missense - nonsense - silent - neutral

nonsense

what type of mutation is this? base pair change that causes a change in the mRNA codon from one encoding an amino acid to a translation stop codon

nonsense

the structure of bacterial chromosomes: bacterial DNA is double-stranded, always circular and organized into a compacted structure a __________ associated with packaging or DNA binding proteins that are histone-like and named _____ and _____

nucleoid HU H

what is this describing? basic unit of eukaryotic chromosome structure

nucleosomes

what is NER stand for and what does it do?

nucleotide excision repair repairs lesions in DNA that distort the regular helix damage usually is caused by exogenous agents such as UV light it impedes DNA replication and transcription

T/F: RNA primer is ~ 5-15 nt long

true

what are inverted terminal repeats?

nucleotide sequences at the ends of the IS element are repeats that are inverted 5' ends are the same sequence repeats can be between 15-40 base pairs in length

what effect of mutation trait is this? altered nutritional requirements and defective biochemical/metabolic pathways

nutritional/biochemical

Nucleosomes are composed of a histone ___________: -2 molecules each of H2A and H2B -2 molecules each of H3 and H4 form a tetramer -therefore, a nucleosome is made up of a tetramer of H3 and H4 and two dimers of H2A and H2B

octamer

what are the commonly used sources of variation applied to human DNA profiling

often variation sin DNA can be revealed by restriction endonucleases to generate prestriction fragment length polymorphisms (RFLP) in addition, VNTRs, SNPs, and STRs provide individual variation suitable for DNA profiling

what are short chains about 20 nucleotides or so long called?

oligonucleotide

describe the difference between a proto-oncogene and an oncogene

oncogene is a mutant form of a proto-oncogene

mutant versions of genes that are normally involved in promoting the cell cycle known as

oncogenes

DNA replication origins with bacteria: bacteria have ______ origin of replication (5'TTAT(C/A)CA(C/A)A3') the binding site for a protein is _____ replication is ___ - directional from this point

one DnaA bi

particular variant of the lambda bacteriophage has a double-stranded DNA genome of 51,365 bp. how long, in units of the length, would this DNA be

one bp is 0.34 nm so 51365 x 0.34=17464 nm

studies of Neurospora led to the ____ hypothesis, whereas studies of human hemoglobin led to the ___ hypothesis

one-gene: one enzyme one-gene: one polypeptide

Mutant versions of genes that are normally involved in promoting the cell cycle are known as A. tumor suppressors. B. proto-oncogenes. C. oncogenes. D. malignant genes. E. attenuators.

onocogenes

what term refers to a continguous genetic complex that is under coordinated complex

operon

operons

palindromic

words such as 'mom' 'dad' and 'live evil' might have special significance when considering the fundamental tools of recombinant DNA tech. what term would be used to describe such words in the context of recombinant DNA tech

palindromic

define merozygote

paritally diploid cell that results when, through recombination, a portion of a donor chromosome is introduced into a bacterium

what is this definition? the percentage of individuals that show at least some degree of expression of a mutant genotype

penetrance (if 20% of mutant individuals show a wild-type like appearance then the mutant gene had an 80% penetrance)

Penetrance

percentage of individuals that show at least some degree of expression of a mutant genotype.

conclusions from hershey-chase: bacteriophage infection of bacteria involves injection of ______ DNA, but not protein into the bacterial cell once phage DNA enters the cell, it can direct phage ___________ ________ as the genetic material

phage reduction DNA

what is this definition? the physical appearance of a trait

phenotype (ex. tall versus dwarf)

what type of genetics is this? studies the frequencies at which various alleles and genotypes occur in a population and how these frequencies change from one generation to the next

population

what is the position effect?

position of a gene or group of genes relative to all other genetic material may affect their expression

In the regulation of lactose operon, the CAP protein exerts ___ control of the structual genes' transcription

positive

___________ repair fixes damaged DNA after it has escaped other repair systems and has failed to be completely replicated

postreplication

what two factors contribute significantly to the wide ranges of genome size among eukaryotes

presence of introns and repetitive sequences is a major contributor, as are the differences in the number of genes

what is this describing? a form of RNA polymerase that synthesizes the primers for DNA replication

primase

In studies of human genetics, usually a single individual brings the condition to the attention of a scientist or physician. When pedigrees are developed to illustrate transmission of the trait, what term does one use to refer to this individual?

proband

in studies of human genetics, usually a single individual brings the condition to the attention of a scientist or physician. when pedigrees are developed to illustrate transmission of the trait, what term does one use to refer to this individual

proband

what is meant by photoreactivation repair

process described in e coli in which UV-induced DNA damage, specifically pyrimidine dimers, can be partially reversed if cells are briefly exposed to light in the blue light range of the visible spectrum

what is a concise definition of proteomics

process of defining the complete set of proteins encoded by a genome

what is this definition? when two independent events occur simultaneously, the combined probability of the two outcomes is equal to the product of their individual probabilities of occurrence

product law of probabilities

what is the expected evolutionary significance of genetic recombination

production of genetic variation

describe the function and general nature of promoters in eukaryotes

promoter regions are necessary for the initiation of transcription. promoters that interact with RNA P II are usually located within 100 bp upstream of a gene and usually contain a TATA box and a CAAT box

What is the general position of the consensus sequence called the GC box? What is its sequence? - promoter; CAAT - promoter; GGGCGG - terminator; CAAT - terminator; GGGCGG - attenuator; GGGCGG

promoter; GGGCGG

describe two classes of proteins known to be involved in the regulation of the cell cycle

protein kinases selectively phosphorylate target proteins. when complexed with cyclins, critical points of the cell cycle are controlled

what is the normal (nonmutant) cellular version of an oncogene called

proto-oncogene

what type of phenotype is this in bacteria? can synthesize all essential organic compounds for growth from a "minimal medium" - single carbon and nitrogen sources and inorganic ions - wild-type for all growth requirements

prototrophs

what are the two types of phenotypes in bacteria?

prototrophs auxotrophs

what are the nitrogenous bases in nucleotides?

pyrimidines (6-membered, single ringed) purines (9-membered, double-ringed)

pyrimidines and purines in DNA

pyrimidines: cytosine and thymine purines: adenine and guanine

prokaryotic ribosomes are consisted of

rRNA and proteins

what is this definition? each gamete receives 1 member of every pair of unit factors, one pair does not influence the segregation of any other pair

random segregation

a cross was made between homozygous wild-type female flies and yellow-bodied male flies. all of the resulting offspring were phenotypically wild-type. offspring of the F2 generation had the following phenotypes: (male:wild:96) (male:yellow:99) (female:wild:197) -is the mutant gene for yellow body behaving as a recessive or a dominant

recessive

what type of allele is this? a wild-type where one copy is enough to survive, but two copies of the mutated allele is lethal

recessive lethal

what type of cell is this in bacterial conjugation? receives the donor genetic material

recipient cells (F-)

we can map a genome through genetic __________ where we move the "houses"/genes instead

recombination

what effect of mutation trait is this? mutations in transcription factors or transcription factor binding sites

regulatory

chromatin remodeling: chromatin fiber, when complexed with histones and folded into various levels of compaction, makes DNA inaccessible to interaction with other important nonhistone proteins, like ________ and _________ unstructured ________ tails are not packed into the folded histone domains within the core of nucleosome histone tails are targets for chemical modifications like __________, methylation and phosphorylation which are very important for gene regulation

replication transcription acetylation

(E. coli is the example for this as shown in the notes) what is ter for replication of E. coli DNA?

replication termination site

an example of a gene product encoded by a regulatory gene is -beta galactosidase enzyme -allolactose -repressor protein -operator

repressor protein

the general term for a non-polymerase protein that binds to an operator

repressor protein

photoreactivation repair: reversal of UV damage UV light is mutagenic and causes pyrimidine dimers it can be _________ if after irradiation cells are exposed briefly to light in the blur range of the spectrum, depends on activity of protein called ____________ ____________

reversed photoreactivation enzyme (PRE)

what are the pentose sugars in nucleotides?

ribose (found in RNA) deoxyribose (found in DNA)

list two major differences between RNA and DNA at the level of the nucleotide

ribose in RNA, deoxyribose in DNA, uracil replaces thymine in DNA

what type of transposon is this in humans? 500,000 copies of 200 to 300 bp elements found in all primates and rodents a 40 bp segment is highly conserved Alu sequences represented in some transcripts flanked by 7-20 bp direct repeats clustering varies between individuals and within one individual

short interspersed elements (SINES)

The initiation of prokaryotic transcription requires ____ for recognizing the promoter sequence

sigma factor

what type of mutation is this? a base pair substitution that alters an mRNA codon but does not change the amino acid sequence of the protein

silent

what type of crossover is this? provide basis for determining the distance between two genes difficult to determine gene order

single

viral genomes for DNA or RNA characteristics?

single or double stranded circular or linear

what is this describing? bind to the unwound, single stranded regions to stabilize the open conformation

single stranded binding protein (SSBPs)

restriction endonucleases are especially useful if they generate 'sticky' ends. what makes an end sticky

single-stranded complementary tails

Assume that investigators crossed a strain of flies carrying the dominant eye mutation Lobe on the second chromosome with a strain homozygous for the second chromosome recessive mutations smooth abdomen and straw body. The F1 Lobe females were then backcrossed with homozygous smooth abdomen, straw body males, and the following phenotypes were observed: smooth abdomen, straw body 820 Lobe 780 smooth abdomen, Lobe 42 straw body 58 smooth abdomen 148 Lobe, straw body 152 Give the gene order and map units between these three loci.

smooth abdomen is in the middle. straw body -------------15------------- smooth abdomen -----5----- Lobe

what type of mutation is this (location based)? occur in non-germline cells and are therefore not inherited, the effect of these mutations may be more pronounced if they occur early in development

somatic

which step is this for the conversion of an F+ strain to Hfr (out of 3)? only A and B genes are transferred into an F- cell which may recombine with the host chromosome, F factor remains in donor cell, so recipient cell remains F-

step 3

in lac operon, the product of structural gene lacZ is capable of

splitting the B-linkage of lactose

n the lac operon, the product of structural gene lacZ is capable of

splitting the β-linkage of lactose

what type of mutation is this? happen naturally, nothing associated with their occurrence, due primarily to random changes in the nucleotide sequence occur in nature and errors in DNA replication and natural chemical processes

spontaneous

mutations that arise in nature, from no particular external agent, are called

spontaneous mutations

what step is in for conversion of Hfr cell to F' cell (out of 5)? excision of the F factor from the chromosome begins during the excision, the F factor sometimes carries with it part of the chromosome

step 1

what step is this for the mating of F+ and F- (out of 5 steps)? during conjugation, the DNA of the F factor replicates with the new copy entering the recipient cell, converting it to F+

step 1

what step is this for the mechanism of bacterial transformation (out of 5)? extracellular DNA binds to the competent cell at a receptor site

step 1

what step is this in BER in mammalian cells? (of 4) DNA glycosylase specific for G-T mismatches usually formed by aminatino of 5'-methyl C to form T flips the base out of the helix and cuts the glycosidic bond

step 1

what characteristic of genetic material is this? must store a vast array of information, the expression of which must be accurately and precisely controlled in order to produce a viable organism

storage of information

what is an allele-specific oligonucleotide

stretch of DNA capable of either base pairing with a specific allele or failing to do so. either way, oligonucleotides can be used, under stringent hybridization conditions, to detect minor differences in DNA sequences

DNA POL I-Mediated DNA synthesis: during each step, a single nucleotide is added to the growing complement of the DNA template using a nucleoside triphosphate as the _________ the release of inorganic ___________ drives the reaction energetically chain elongation occurs in a 5' to 3' direction, that is the next nucleotide is added to the 3' _____ group of the previously added nucleotide

substrate pyrophosphate OH

the watson-crick model of DNA: the ribbon-like strands constitute the __________ - _____________ backbones horizontal rungs constitute the __________ base pairs

sugar-phosphate nitrogenous

are eukaryotic okazaki fragments smaller or larger than prokaryotic?

swmaller (10x)

what is the specific application of reverse transcriptase in the preparation of cDNA

synthesis of DNA from a single-stranded RNA template to form an RNA-DNA duplex

reverse transcriptase is an enzyme found in association with retroviral activity. it has property of

synthesis of DNA from an RNA template

many human genetic diseases are the result of mutations in enzymes in nutritional and /or biochemical pathways what disease/syndrome is this? defect in N-acetylhexosaminidase A, results in processes gangliosides in brain cells causing neurodegeneration

tay-sachs

what is a good example of incomplete dominance in humans?

tay-sachs disease (heterozygotes express only 50% of the enzyme activity found in homozygous normal individuals)

structures located at the ends of eukaryotic chromosomes are called

telomeres

what is this describing? ends of linear chromosomes, help preserve the integrity and stability of the chromosomes characterized by repeating sequences that are G-rich in most organisms humans - 5'-TTAGGG-3' tetrahymena - 5'-TTGGGG-3'

telomeres

the discontinuous aspect of replication of DNA in vivo is caused by

the 5' to 3' polarity restriction

A leading hypothesis regarding the source of some transposable elements is the integration into the genome of a virus. What evidence supports this hypothesis?

the conservation of some gene sequences between transposable elements and extant viral genes

DNA replication in vivo requires a primer with a free 3' end. what molecular species provides this 3' end, and how is it provided

the free 3' end is provided by an RNA primer, which is provided by the enzymatic activity of the RNA primase

(E. coli is the example for this as shown in the notes) what is the replicon in replication of E. coli DNA?

the length of DNA that is replicated following replication initiated at a SINGLE origin, the entire chromosome is a SINGLE REPLICON

explain why lacOc mutations are cis-acting while lacI mutations can be trans-acting

the operator region does not produce a diffusible product, while the lacI gene goes.

when both glucose and lactose are present in the medium, ___ in the e coli cells

the operator will not bind the repressor, the structural genes will not be transcribed

(E. coli is the example for this as shown in the notes) what is oriC for replication of E. coli DNA?

the origin of replication that is a SINGLE origin, single chromosome

Which of the below is not true about the location of enhancers? - They can be found upstream of the transcription initiation site - They can be found downstream of the promoter - They can be found in introns - they can be found 3' of the polyadenylation site - the position of the enhancer has no effect on gene regulation

the position of the enhancer has no effect on gene regulation

describe the cellular and molecular function of the ras gene family and the consequences of mutations in ras

the ras gene family encodes a protein of 189 amino acids, which is involved with signal transduction in the cell membrane. point mutations may cause changes in function that promote abnormal signaling, thus stimulating uncontrolled cell growth

It is possible for a repressor to negatively regulate the expression of an operon because - the repressor induces the expression of inducer - one of the genes expressed in the operon negatively regulates the repressor - the repressor binding site overlaps the promoter site of the operon allowing it to physically block the binding of RNA polymerase - the repressor binding site on the DNA overlaps with the translation start site

the repressor binding site overlaps the promoter site of the operon allowing it to physically block the binding of RNA polymerase

This question relates to the regulation of enzymes involved in the synthesis of tryptophan in E. coli. If tryptophan is present in the medium and available to the bacterium, - the repressor is inactive and the tryptophan operon is "off" - the repressor is inactive and the tryptophan operon is "on" - the repressor is bound to the operator, thus blocking transcription - the five structural genes associated with tryptophan synthesis are being transcribed at "induced" levels - positive control is occurring

the repressor is bound to the operator, thus blocking transcription

By their experimentation using the Neurospora fungus, Beadle and Tatum were able to propose the far-reaching hypothesis that

the role of a specific gene is to produce a specific enzyme

The primary structure of a protein is determined by

the sequence of amino acids

when two proteins show a 50 to 70 percent match in amino acid sequence, it is likely that

the two proteins share a common ancestory

the genetic code is said to be triplet, meaning that

there are three bases in mRNA that code for amino acid

what are the roles of the recBCD genes

they function in bacterial recombination

because of the wobble hypothesis, the ___ position of a genetic codon can be flexible in defining amino acid

third

Regarding eukaryotic and prokaryotic genetic regulation, what process seems to be the most similar between the two?

transcriptional regulation

regarding eukaryotic and prokaryotic genetic regulaiton, what process seems to be the most similar between the two

transcriptional regulation

When referring to attenuation in regulation of the trp operon, it would be safe to say that when there are high levels of tryptophan available to the organism,

transcriptional termination is likely

When referring to attenuation in regulation of the tryptophan operon, it would be safe to say that when there are high levels of tryptophan available to the organism, - the tryptophan operon is being transcribed at relatively high levels - translational termination is likely - transcriptional termination is likely - tryptophan is inactivating the repressor protein - ribosomes are stalling during translation of the attenuator region

transcriptional termination is likely

is this statement true for single crossover events? crossover must occur between the alleles of two different genes in order to be detected phenotypically

true

assume that you are working with a mutant, nutritionally deficient strain of E.coli and that you isolate revertants, which are nutritional. describe the molecular level, two possible causes for the reversion to wild time.

two general classes of events could be involved: true reversion would involve a precise correction in some other part of the mutant gene product serves to "compensate" for the original mutation. in intragenic suppression, a mutation in some other gene, such as as transfer RNA, serves to compensate for the original mutation.

what are the three important hypothesis by mendel? - _______ _______ exist in pairs - dominance and _____________ - ____________

unit factors recessiveness segregation

what are the seven key issues that must be resolved during DNA replication? -__________ of helix -reduction of increased _________ generated during unwinding -synthesis of _______ for initiation -discontinuous synthesis of ________ strand -removal of the RNA __________ -joining of _______________ DNA to adjacent strand - proofreading

unwinding coiling primer second primers gap-filled

what does VNTR stand for? and what is it?

variable number tandem repeats 15-100 bp long (minisatellites) variation between individuals is the basis of DNA fingerprinting

VNTRs are sections of DNA with the following characteristics

variable numbers of tandem repeats, variable in the population

what characteristic of genetic material is this? mutations are the source of genetic variation that ultimately is reflected in specific proteins being expressed

variation through mutation

griffith's transformation experiment used different strains of diplococcus pneumoniae __________ strains: cause pneumonia in humans and mice __________ strains: DO NOT cause pneumonia

virulent avirulent

what type of allele is this? occur most frequently in a population, usually dominant, gene product is functional

wild type (has a wild type phenotype present)

A. histones

A. phosphorus and sulfur.

corn kernel development: corn with a ____ gene for kernel color have colored kernels, a mutant gene produces colorless (or yellow) kernels Mutation is caused by insertion of ___ into the gene If Ac is also present in can cause reversions, which induces the ____ transposition out of the gene Any cells in which ___ has transposed out will produce pigment which results in spotting of the kernel the size of the spot is determined by when the reversion takes place during kernel development

wt Ds Ds Ds

x-linked

what type of gametic mutation is this? expressed in hemizygous males if that male inherits the affected allele

x-linked

hemizygosity would most likely be associated with

x-linked inheritance

UV light causes pyrimidine dimers to form in DNA, some individuals are genetically incapable of repairing some dimers at 'normal' rates. such individuals are likely to suffer from

xeroderma pigmentosum

are centromeric sequences heterochromatic?

yes

are there alternating major or minor grooves apparent along DNA axis?

yes

does the interrupted mating technique demonstrate an ordered transfer of genes from an Hfr to an F- strain?

yes

can bacterial transformation be another technique for genetic mapping?

yes (ONLY IF the recombinant DNA produces a different phenotype than the original phenotype of the recipient strain)

zero

assuming independent assortment, what proportion of the offpsring of the cross AaBbCcDd x AabbCCdd will have the aabbccdd genotype

zero

in a mating between individuals with the genotype IAIB x IOIO, what percentage of the offspring are expected to have the O blood type

zero

The secondary structure of a protein includes

α-helix and β-pleated sheet

Viral chromosomes exist in a variety of structures and can be made up of the following: A. protein or lipid coding sequences. B. DNA only. C. DNA or RNA. D. RNA only. E. DNA, RNA, or protein.

C. DNA or RNA.

The basic structure of a nucleotide includes the following components: A. amino acids. B. tryptophan and leucine. C. base, sugar, and phosphate. D. mRNA, rRNA, and tRNA. E. phosphorus and sulfur.

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