genetics final
which of the follow is false? -generally chromosomes of prokaryotes are circular -prokaryotes usually have a single molecule of DNA -generally, chromosomes of eukaryotes are circulat -eukaryotes usually have multiple chromosomes -eukaryote chromosomes are usually linear
generally chromosomes of eukaryotes are circular
which of the following treatments of maternal mice is associated with hyper-methylation of the agouti locus in their progeny? -BPA -cigarette smoke -folic acid -high fat diet -non nurturing mother
folic acid
forward vs reverse genetics
forward: -mutation--> phenotype --> gene -start with mutagen, make loads of progeny with mutation, screen for mutant gene, isolate gene reverse: gene --> disruption mutation -->phenotype
which of the following components allows for gene-specific targeting of Cas9 in the experimental CRISPR system? -crRNA -donor DNA -RISC -tracrRNA -gRNA
gRNA
which type of chromosome mutation increases the amount of genetic material for all chromosomes? -polyploidy -aneuploidy -translocation -inversion -duplication
polyploidy
what are two differences between prokaryotic and eukaryotic translation initiation?
(1) Initiation in prokaryotes begins with a formyl-methionine. In eukaryotes, it begins with methionine. (2) Prokaryotic and eukaryotic ribosomes are different sizes, require different ribosomal subunits or initiation. (3) Recognition of the start codon is different. Prokaryotes have an rRNA that binds to the mRNA. Eukaryotic recognition of the start codon involves the 5' cap, the 3' poly(A) tail, and the Kozak sequence near the start codon. (4) Prokaryotic initiation factors are different.
describe two ways in which an inversion can alter gene expression
(1)Position effect: Inversions may reposition alleles in different genomic contexts, which may significantly alter their expression. For example, alleles may be repositioned to a heterochromatic region and be inhibited or to a highly active region and be induced (2) Gene disruption: Because inversions involve cutting pieces of chromosomes and splicing pieces of chromosomes back together, gene sequences may be disrupted. Breakpoints can occur in gene regulatory regions, coding domains, introns, and so forth, any or all of which may ultimately alter phenotypic expression. (3) Gene fusions: A break point in two genes are fused together and may result in altered phenotypic expression.
what are the 3 steps of a PCR cycle?
-95 C: denaturing DNA -50-60 C: annealing primers -72 C: DNA synthesis
Codominance and incomplete dominance are two concepts that seem similar, but are slightly different. Explain the difference. Use examples.
-ABO is and example of codominance. HbS and HbA (sickle cell alleles) are also codominant. In co-dominance, both versions of the protein are expressed by the cell and confer a phenotype. -Incomplete dominance occurs when the heterozygote has an intermediate phenotype between the homozygotes such as RR = red, Rr = pink, rr = white.
you discover a certain species of weed growing in soil contaminated with toxic PCBs and later determine that the PCB resistance is due to a single dominant allele. If 45% of the seeds from a randomly mating population of resistant weeds will germinate in contaminated soil, what is the frequency of the PCB-resistance allele? Among all the plants that germinate, what proportion will be heterozygous? What proportion will be homozygous dominant?
-Because 45% of the seeds germinate, the 55% that do not germinate must be homozygous recessives (q2). The frequency of the recessive allele (q) is therefore (0.55)1/2 = 0.742; the frequency of the dominant resistance allele = p = 1 - q = 1 - 0.742 = 0.258. -The expected frequency of heterozygotes = 2pq = 2(0.258)(0.742) = 0.383, and the overall frequency of surviving genotypes that are heterozygotes = (0.383)/(0.45) = 0.85 (85%). -The expected frequency of homozygous dominants = p2 = (0.258)2 = 0.067, and the overall frequency of surviving genotypes that are homozygote dominant = (0.067)/(0.45) = 0.15 (15%).
what things do you need in a PCR reaction?
-DNA template: need something to replicate -DNA polymerase to synthesize new DNA -dNTPS: the building blocks of DNA -oligonucleotide primers-need to prime DNA synthesis and provide specificity
"Mitochondrial Eve" is the name given to the idea that all humans alive today can trace their mitochondrial ancestry to a single African female alive around 150,000 years ago. What feature of mitochondrial inheritance makes this a reasonable conjecture?
-Mitochondrial Eve is the most recent common matrilineal ancestor of all humans as measured through the mitochondria. mtDNA is maternally inherited, but more importantly, there is no recombination between parental genomes as is the case with nuclear genes. Therefore, it is possible to easily follow the inheritance of the mitochondria from generation to generation. -Mitochondrial DNA is inherited from your mother only.
what are the steps of eukaryotic pre-mRNA processing?
-addition of 5' cap -splicing out introns from the pre-mRNA -recognition and binding the 3' AAUAAA sequence by specific protein factors -addition of poly A tail -export to the cytoplasm
what are restriction enzymes?
-discovered in bacteria -used to cut up foreign DNA; can do this because bacteria methylate their own DNA and the enzyme can't cut through methylated DNA -can cut at specific 6-bp sequence in staggered manner to leave stranded overhangs: sticky ends or in a blunt matter with no overhangs: blunt ends
what are mendels conclusions?
-each parent has two factors (principle of diploidy) -each parent contributes one 'factor' to the next generation (principle of segregation) -one 'factor' dominates the other (principle of dominance) -alleles behave like particles
describe androgen-insensitivity syndrome
-have XY chromosomes, and testes that produce testosterone, but female appearance -SRY gene normally causes the gonads to develop into testes, which produce testosterone, which stimulates embryonic tissues to develop male characteristics -testosterone must bind androgen receptor, which is defective is AIS, so female characteristics develop -androgen receptor gene is on X chromosome
List two dosage compensation strategies for equalizing the amount of sex chromosome gene products and an example of an organism that uses that dosage compensation strategy.
-inactivation of one sex chromosome in the homogametic sex; humans -halving the activity of genes on both sex chromosomes in the homogametic sex; c. elegans -increasing the activity of genes on the sex chromosome in the heterogametic sex; drosophilia
what are important things to look for when transcribing an mRNA?
-look for start codon (AUG) -add 5' on front end, and 3' on back end when writing the sequence -add N- to front end and -C to back end when writing amino acid sequence
describe the chromosomal sex-determining systems XX and XY
-males and females have the same number of chromosomes -females are homogametic, XX -males are heterogametic, XY -Y chromosome is acrocentric -many organisms including some plants, insects, reptiles and all mammals including humans use this
describe the chromosomal sex-determining systems ZZ and ZW
-males and females have the same number of chromosomes -females are heterogametic, ZW -males are homogametic, ZZ -found in birds, some reptiles, butterflies, some amphibians and some fishes
what are the 4 major types of chromosomes?
-metacentric: centromere is at middle; p and q are equal -submetacentric: p and q are close in length but p is slightly shorter -acrocentric: centromere is near one end but not right on it -telocentric: centromere is at or near the tip of the chromosome
what is a missense, nonsense and silent muation?
-missense is a point mutation that results in a different amino acid being inserted -a point mutation that that inserts a stop codon -silent mutation is a point mutation in which the same amino acid is inserted
what is a tumor supressor and when does mutation cause problems?
-normal function is to inhibit cell cycle, positively regulate apoptosis, role in DNA repair -mutations need to be preset in both alleles, this means that it loses the ability to release an inhibitory factor
what do primase, ligase, DNA polymerase I, DNA polymerase III, single-stranded DNA binding protein, helicase, and topoisomerase do?
-primase: synthesizes RNA primer -ligase: covalently links the okazaki fragments together -DNA polymerase I: excises the RNA primers and fills in with DNA -DNA polymerase III: synthesizes a daughter strand of DNA -single stranded DNA binding protein: keeps the parental strands apart so they don't come back together after they are separated -helicase: breaks the hydrogen bonds between the DNA strands -topoisomerase: relieves the stress from supercoiling
which of the following is true with regards to the human genome? -Scientists do not know the function of most sequences in the human genome. -There is more diversity between human genomes than there is in any other organism -greater than 40% of the human genome has homology to transposons. -On average, any two human genomes vary by about 1 nucleotide in every 1000. -The human genome is made up mostly of regions that encode proteins and RNAs. -the most common type of genetic variation in the human genome are SNPs
-scientist do not know the function of most sequences in the human genome -greater than 40% of the human genome has homology to transposons -on average, any two human genomes vary by about 1 nucleotide in every 1000 -the most common type of genetic variation in the human genome are SNPs
describe dosage dependent sex determination in drosophila
-sex is determined by ration of X chromosomes to autosomes (X:A) -above 1=female -.5= male -anything in between give you intersex species and you get characteristic of both -related to gene balance and not necessarily the ratio; more autosomes means you have a shorter amount of time for X chromosomes can have their affect
describe the chromosomal sex-determining systems XX and XO
-simplest mechanism of chromosomal sex determination -females have two X chromosomes (XX) -males have one X chromosome (XO) -males produce two different gametes and are therefore heterogametic sex -females produces two of the same gamete and are therefore homogametic sex
Miniature wings in Drosophila are due to an X-linked allele (Xm) that is recessive to the wild-type allele for normal long wings (X+). Sepia eyes are produced by an autosomal allele (se), which is recessive to the wild-type allele for red eyes (se+). A female that is homozygous for normal wings and has sepia eyes is crossed with a male that has miniature wings and is homozygous for red eyes. The F1 offspring are intercrossed to produce the F2 generation. What proportion of the F2 females is expected to have miniature wings and sepia eyes?
0
Suppose that in a population the frequency of a particular recessive condition is 1/400. Assume the presence of only a dominant allele (A) and a recessive allele (a) in the population and that the population is at Hardy-Weinberg equilibrium. What is the frequency of heterozygotes in the population?
0.095
Two pea plants with purple flowers are crossed. Among the offspring, 63 have purple flowers, and 17 have white flowers. Perform a chi-square test and determine if the difference between observed and expected could be a result of chance. what is the chi-square value? how many degrees of freedom? could this result be expected by chance?
0.6 1 get value of 5% so we do not reject the hypothesis that the difference between the observed and expected are result of chance
describe two ways that eukaryotic transcription is different from prokaryotic transcription
1) There are many different eukaryotic RNA polymerases. Each recognizes the promoter of a different type of gene. (2)Eukaryotic RNA polymerases require general transcription factors to associate with a promoter. (3)Eukaryotic promoters do not have the same -10 and -35 consensus sequences that prokaryotic promoters have. (4) Eukaryotic RNA polymerases do not have the polymerase subunits that are required for promoter recognition. (5) Eukaryotic transcription initiation requires altering or removing nucleosomes at the gene to be transcribed. 6) Prokaryotes use Rho-dependent and intrinsic termination 7) Larger Larger eukaryotic genomes have more genes to recognize and transcribe than prokaryotes 8)Eukaryotes have more noncoding DNA, genes further apart making it more complex 9) Eukaryotes require more proteins at the promoter 10) Eukaryotes have a nucleus, which is where transcription occurs, while in prokaryotes it occurs in cytoplasm 11) In eukaryotes RNA must be processed before leaving the nucleus 12) Template for transcription is organized into chromatin in eukaryotes
In animals, the inability to make the pigment melanin results in albinism, a recessive condition. Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa). What is the probability that the second and third children will also have albinism?
1/16
Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. What is the probability of producing an AABB zygote from a cross of AaBb × AaBb?
1/16
A man has a condition where all of his gametes undergo nondisjunction of the sex chromosomes in meiosis I, but meiosis II proceeds normally. He mates with a woman who produces all normal gametes. What is the probability that the fertilized egg will develop into a child with Turner syndrome (XO)? Assume that all gametes and zygotes are viable.
1/2
assume that the diploid or 2n number of chromosomes is 18 for a certain species of animal. How many DNA molecules will be found in metaphase II for this species?
18
If both husband and wife are known to be heterozygous for the autosomal recessive condition of albinism, what is the probability that among their four children, three will be normal and one will have albinism?
27/64
Assume that during DNA replication in a bacterium a mistake is made and a G is inserted into the newly synthesized DNA strand opposite a T in the template DNA strand. If this mistake is not repaired before the next round of DNA replication, what mutation will eventually result?
A to G base substitution transition mutation
In dogs, black coat color (B) is dominant over brown (b), and solid coat color (S) is dominant over white spotted coat (s). A cross between a black, solid female and a black, solid male produces only puppies with black, solid coats. This same female was then mated with a brown, spotted male. Half of the offspring from this cross were black and solid, and half of the offspring were black and spotted. What is the genotype of the female?
BBSs
which of the following is not true of gel electrophoresis? -gels can be used to separate proteins, DNA, and RNA -gels can be used to separate macromolecules by size -DNA and RNA will move toward the negative side of a gel -protein gels have a different composition than nucleic acid gels -all are true
DNA and RNA will move toward the negative side of a gel
how do DNA and RNA differ? -DNA is composed of repeating units called nucleotides, while RNA is composed of repeating units called amino acids. -DNA is composed of repeating units called amino acids, while RNA is composed of repeating units called nucleotides -In DNA the nucleotides contain a sugar, a base, and a phosphate, while in RNA the nucleotides contain no sugar -DNA contains the nitrogenous base thymine while RNA contains the base uracil instead of thymine. -DNA contains the nitrogenous base guanine, while RNA contains the base cytosine instead of guanine.
DNA contains the nitrogenous base thymine while RNA contain the base uracil instead
what experiment are each used in? GFP reporter gene RNA-seq chromatin immunoprecipitation CRISPR microarray
GFP: determining where a gene is expressed in a living organism RNA-seq: identifying all the coding regions of a genome CIP: isolating DNA fragments that are associated with a particular histone protein modification CRISPR: modifying an organisms genome in a targeted manner microarray: comparing the SNPs between two individual genomes
which of the following would be associated with heterchromatin? -HDAC -HDM -a protein containing a bromodomain -an enhancer element -a repressor protein
HDAC
Explain why mitosis does not produce genetic variation and how meiosis leads to the production of tremendous genetic variation
Mitosis produces cells that are genetically identical to the parent cell. Meiosis includes two distinct processes that contribute to the generation of genetic variation: Crossing over shuffles alleles on the same chromosome into new combinations, whereas the random distribution of pairs of homologous chromosomes, one member of each pair coming from the mother and the other from the father, shuffles alleles on different chromosomes into new combinations.
which of the following components of the Gal system is responsible for activation of the enzyme gene in cis? -gal4 -Mig1 -Gal3 -galactose -UAS
UAS
how is chi-square calculated?
X^2= summation of (o-e)^2/e o is the number of observed individuals with a given phenotype e is the expected individuals with a given phenotype
what would be the most likely effect of mutating the consensus sequence found at the 5' splice site of an intron? -a shorter than normal protein would be produced -replication would be inhibited -a longer than normal DNA would be produced -a longer than normal mRNA would be produced -transcription would terminate prematurely
a longer than normal mRNA would be produced
which of the following is not true with regards to the lin-4 and lin-14 genes in C elegans? -The lin-4 region does not contain a protein encoding gene (open reading frame). -The lin-4 region contains sequences that are complementary to the lin-14 mRNA -In recessive lin-4 mutants, cell division is delayed relative to wild-type - lin-14 loss of function mutants display precocious (accelerated) cell division - A loss of function mutation in lin-14 results in deletion of a portion of the 3'-UTR
a loss of function mutation in lin-14 results in deletion of a portion of the 3' UTR
n humans, occasionally a baby is found that has the XX chromosomal karyotype but is phenotypically male. Which of the following statements might be a CORRECT explanation for at least some of these unusual cases? -An extra pierce of autosomal chromosome 15 is probably present in the genome but is too small to be detected. -A small piece of autosomal chromosome 15 is missing but is too small to be detected. -A piece of chromosomal material containing an active SRY gene is found attached to one of the X chromosomes -A mutation has occurred in the SRY gene making it inactive. -The ratio of number of X chromosomes to number of sets of chromosomes is incorrect.
a piece of chromosomal material containing an active SRY gene is found attached to one of the X chromosomes
Males heterozygous for a gene F are inflexible. Females heterozygous for this gene are flexible. When a heterozygous male and heterozygous female have children, 3/4's of the males are inflexible and 1/4 are flexible. Conversely, 3/4's of the females are flexible and 1/4 are inflexible. This is an example of:
a sex- influenced trait
mice that are homozygous for a complete deletion of the wild-type gene "T" develop multiple tumors in a variety of tissues very early in life. Gene "T" is most likely -an activated oncogene -an oncogene -a proto-oncogene -a tumor suppressor gene
a tumor suppressor gene
the aminoacyl-tRNA synthetase enzymes are responsible for: -synthesizing tRNA molecules in the nucleus from rRNA genes -regulating the process of amino acid synthesis -catalyzing the enzymatic step of peptide bond formation during translation -adding amino acids to appropriate tRNAs (charging the tRNA) -matching each tRNA with the appropriate mRNA codon
adding amino acids to appropriate tRNAs
which of the following observations/phenomenon did not lead to the idea of epigenetics? -position effect variegation in drosophila -identical twins have the same genome sequence, but can have different phenotypes -prader-willi syndrome and angelmans syndrome are caused by the same chromosomal deletion -all genes have similar proximal promoters
all genes have similar proximal promoters
telomerase uses _____ to synthesize new dna -exonuclease activity -a licensing factor -strand invasion -an RNA template -a DNA template
an RNA remplate
most cancers are assumed to arise through which of the following? -an accumulation of genetic or epigenetic changes in somatic cells -errors in transcription -the production of unbalanced gametes because of nondisjunction during meiosis -delayed cell division during early embryogenesis -No correct answer is provided.
an accumulation of genetic or epigenetic changes in somatic cells
which of the following reagents would you use to isolate specific protein from a solution? -an antibody -a probe -beta galactosidase -BPA -none of the above
an antibody
autopolyploidy vs allopolyploidy
autopolyploidy is complete nondisjunction, increase in number of chromosome sets allopolyploidy is the result of interspecies crossed; contain two or more sets of chromosomes from two or more species
what would be the consequence of a diploid gamete (resulting from meiotic nondisjunction) being fertilized by a haploid gamete from the same sequence? -autotriploid -allotriploid -allotetraploid -autotetraploid -autodiploid
autotriploid
in order to be functional, a eukaryotic chromosome requires all of the following except: -centromere -origins of replication -centrosome -telomeres
centrosome
paracentric vs pericentric
both are inversions -paracentric does not include the centromere and both breaks happen in one arm of the chromosome -pericentric does include the centromere and there is a break in each arm
which of the following statements is TRUE regarding transcription in most organisms? -all genes are transcribed from the same strand of DNA -both DNA strands are used to transcribe a single gene -different genes may be transcribed from different strands of DNA -the DNA template strand is used to encode double-stranded RNA -the DNA nontemplate strand is used to encode single-stranded RNA
different genes may be transcribed from different strands of DNA
which of the following DNA repair systems does NOT involve the activity of a DNA polymerase? -mismatch repair in humans -nucleotide-excision repair in yeast -base-excision repair in E. coli -direct repair of thymine dimers in E. coli -all are correct
direct repair of thymine dimers in E. coli
which of the following is not a form of aneuploidy in diploid organisms? -nullisomy -monosomy -disomy -trisomy -tetrasomy
disomy
Two hairless hamsters are crossed and 2/3 of the progeny are hairless while 1/3 have hair. What concept is illustrated?
dominant lethal allele
euploidy vs aneuploid
euploidy is changes in whole chromosome sets; diploid, triploid, etc anaeuploidy is a change in parts of chromosomes sets; nullisomy, disomy, trisomy etc
which of the following was not one of mendel's conclusions based on his monohybrid crosses? -alleles exist in pairs -alleles segregate equally into gametes -alleles behave as particles during inheritance -genes are carried on chromosomes -one allele can mask the expression of the other allele
genes are carried on chromosome
In an effort to identify the influence of genetic factors on both Type 1 diabetes and Type II diabetes, researchers calculated concordance rates for monozygotic twins. Concordance rates of 30-50% have been found for Type I diabetes with concordance rates of 80% for Type II. For both kinds of diabetes, dizygotic concordance rates were about 15%. What does this information suggest concerning the relative effect of genetic and environmental factors for each type of diabetes? -Genetic factors have little or no role in the occurrence of Type I diabetes. -Type II diabetes is primarily determined by nongenetic factors. -Type II diabetes appears to be caused by a single unidentified gene -Genetic influences exert a larger role in Type II diabetes than in Type I diabetes. -Environmental factors have no role in the occurrence of either type of diabetes.
genetic influences exert a larger role in type II than in Type I diabetes
how do germ-line (gamete) mutations differ from somatic mutations? -Germ-line mutations involve small changes to DNA such as base-pair substitutions, while somatic mutations usually involve large deletions. -Germ-line mutations can be passed on to offspring, while somatic mutations cannot. -Germ-line mutations occur during DNA replication, while somatic mutations do not. -Germ-line mutations are reversible, while somatic mutations are not. -Germ-line mutations result in cancers, while somatic mutations do not.
germ-line mutation can be passed on to offspring, while somatic mutations cannot
You wish to clone the boxed and shaded region of DNA into a plasmid. The restriction sites in the plasmid (MCS) and your DNA are shown. Unfortunately, you cannot find an enzyme that is unique to the plasmid and also cuts on either side of the shaded region. describe one way you could add a restricction site that is present in the plasmid to either end of the shaded region of DNA
include the restriction site in a gene specific primer and do PCR or include the restriction site in a linker and ligate onto the end of the cDNA or the PCR fragment
Ten individuals are homozygous for a dominant allele that causes polydactyly (extra digits). These ten individuals display varying degrees of the phenotype from completely normal digits in one individual to a small extra digit in some individuals to a completely formed extra digit in other individuals. Which concept best applies to the individual that is completely normal (no extra digits)?
incomplete penetrance
With regard to E. coli's response to lactose, the lac operon is which kind of system? with glucose?
inducible and negative repressible and positive
which one of the following topics of research belongs to the discipline of transmission genetics? -mechanism of DNA replication -gene expression patterns -evolution -chemical modifications of nucleic acids -inheritances pattern of gene alleles
inheritance patter of gene alleles
which of the following mutagens is most likely to cause a frameshift mutation? -base analog -alkylating agent -intercalating agent -ionizing radiation -UV light
intercalating agent
when is reverse transcription useful and what is it?
it is a DNA version of an mRNA molecule; RNA gets copied to DNA because it is more stable it is useful when you want a copy of eukaryotic genes that do not contain introns
which of the following mutations in a parent could result in small progeny? -loss of function mutation in one of the mothers H19 genes -loss of function mutation in one of the father H19 genes -loss of function mutation in one of the mother Igf2 genes -loss of function mutation in one of the father Igf2 genes -loss of function mutation in the CTCF gene in either parent
loss of function mutation in one of the fathers Igf2 genes
Which of the following mutations would NOT affect epigenetic marks? -Loss of function mutation in the XIST gene -Deletion of the ICR site near the Igf2 gene -Loss of function mutation in a gene encoding a barrier insulator -Loss of function mutation in the gene encoding a component of the SWI/SNF complex -Loss of function mutation in the Igf2 coding region
loss of function mutation in the Igf2 coding region
with the XX-XO sex determination system, generally: -female offspring have one X chromosome, an it is inherited from their father -male offspring have one X chromosome and it is inherited from their mother -male offspring have one X chromosome and it is inherited form their father -female offspring have one X chromosome and it is inherited from their mother -male offspring have two X chromosomes, one inherited from each parent
male offspring have on e X chromosome and it is inherited from their mother
what is the effect of bisulfite treatment?
non-methylated C residues are converted to U's
what would the expression level of the Z and Y genes in the absence of both glucose and lactose?
off
what are oncogenes and proto-oncogenes?
oncogene -they are proto-oncogenes that have been mutated and no longer stop at cell checkpoints to ensure normal growth -mutation of oncogene needs to only be present in one allele proto-oncogenes -active only when proper signal allows -many positively regulate cell-cycle other act to inhibit apoptotic pathway -mutations lead to continuous unregualted express; it no longer goes back and forth between active and inactive
two chromosomes have the following segments, where - represents the centromere. KLM-NOPQR STUV-WXYZ which type of chromosome mutation would result in the following chromosomes? KLM-NORQP STUV-WXYZ
paracentric inversion
paralog, ortholog, pseudogene, parsimony
paralog: genes within an organism that arose out of gene duplication ortholog: genes in separate organisms that came from a common ancestral gene pseudogene: a gene that has lost its function parsimony: the easiest conclusion is usually correct
penetrance vs expressivity
penetrance: the percentage of individuals with a given allele who exhibit the phenotype associated with that allele expressivity: measures the degree to which a given allel is expressed at the phenotypic level; the intensity of the phenotype
describe population genetics, transmission genetics and molecular genetics
population: studies genetic variation and changes in genes and allele frequencies within groups of individuals of the same species over time (over many populations) transmission: concerned with the inheritance of genes from one generation to the next and also deals with the location of genes on chromosomes and gene mapping (from parents to offspring) molecular genetics: focuses on the structure, organization and function of genes at the molecular level; concerned with the processes by which genetic information is transferred and expressed (from DNA to gene action)
In the presence of the sugar maltose (a substrate), E. coli activate the enzymes required for breaking maltose down into monosaccharides. An activator protein is responsible for turning the transcription of the enzymes on. This system is an example of:
positive regulation and induction
which of the following elements would not be found in an mRNA molecule? -protein coding region -3' untranslated region -5' untranslated region -promoter -start and stop codons
promoter
Place the items of the following list into the proper categories below based on how they are involved in gene regulation. categories: -promotion of heterochromatin, promotion of euchromatin, transcriptional initiation, mRNA regulation items: -HMT, lin-4 miRNA, GTA, chromodomain containing proteins, HAT, distal promoter, gal80, tup1, XIST RNA, 3' UTR of an mRNA
promotion of heterochromatin: -HMT -chromodomain containing proteins -Tup1 -XIST RNA promotion of euchromatin: -HAT transcriptional initiation: -GTA -distal promoter -Gal80 mRNA regulation -lin-4 miRNA -3' UTR of an mRNA
which of the following are types of posttranslational processing that will not occur in a prokaryote? -addition of a phosphate group to protein -removal of a phosphate group to protein -protein folding -cleavage of mitochondrial targeting sequence
protein folding
which of the following does not bring about evolution in a population? -small population size -migration of individuals from a population with a different genetic structure -mutation -selection -random mating
random mating
Eggplant shape is controlled by alleles of two different genes A/a and B/b. Two round eggplant are crossed and all of the progeny are long. These long eggplant are then intercrossed and produce 18 long eggplant, 12 round eggplant, and 2 oval eggplant. What is the genotype(s) of each of the classes? Round long oval
round: aaB_ and A_bb long: A_B_ oval: aabb
Familial vitamin-D-resistant rickets is an X-linked dominant condition in humans. If a man is afflicted with this condition and his wife is normal, it is expected that among their children, all the daughters would be affected and all the sons would be normal. In families where the husband is affected and the wife is normal, this is almost always the outcome among their children when such families have been studied. Very rarely an unexpected result occurs in such families where a boy is born with the disorder. If the chromosomes of such unusual boys are examined, what might be expected to be found? -Some of the boys are XYY. -Some of the boys are XY but have lost the SRY gene from their Y chromosome. -Some of the boys are YY. -Some of the boys are XXY. -Some of the boys are XXX.
some of the boys are XXY
mutations that affect the allosteric binding site for lactose of the lac repressor (I gene) lead to what phenomenon?
super repression
you have a drug that blocks the activity of primase. which of the following would be affected by this drug? -synthesis of a complete lagging strand -syntheses of a complete leading strand -synthesis of both a complete leading strand and a complete lagging strand -no effect, both strands a synthesized normal
synthesis of both complete leading and lagging strand
whereas the nucleotide strand used for transcription is termed the ______, the nontranscribed strand is called the ______?
template strand, nontemplate strand
if a deletion occurs in a gene that encodes DNA polymerase I and no functional DNA polymerase I is produces, what will be the most likely consequences of this mutation? -the DNA will not be able to unwind to initiate replication -there would be no RNA primers laid down -the DNA would not exist in a supercoiled state -the DNA strands would contain pieces of RNA -there would be no DNA replication on the leading or lagging strands
the DNA strands would contain pieces of RNA
Alfred Hershey and Martha Chase examined transformation using bacteriophage (bacterial DNA virus) and bacterial cells. If phage are labeled with radioactive phosphate and allowed to infect bacterial cells, the radioactive phosphate will be localized to: -newly synthesized phage viruses in the host bacterial cell -the outside of infected cell (in phage ghosts) -the inside of infected cells (in phage DNA) -no radioacctivity will remain after infection -the phosphate will be metabolically consumed, and therefore the radioactivity will be destroyed
the inside of infected cells
how do you know the difference between the leading and the lagging strand?
the leading strand is being built (5' to 3') in the direction of the replication fork
which of the following statements is false concerning prokaryotic cells? -They lack a nuclear membrane. -They lack organelles such as chloroplasts. -They are less complex than eukaryotic cells -They lack genetic information. -They lack a true nucleus.
they lack genetic information
which of the following is true only of prokaryote (and not eukaryotes)? -DNA is associated with histone proteins -chromosomes are linear -genes are regulated as individual units -the ground state of transcription is off -transcription and translation are coupled
transcription and translation are coupled
what is a transition vs a transversion?
transition are purine to purine (A to G) or pyrimidine to pyrimidint (C to T) transversions are purine to pyrimidine
A geneticist is studying a mutation in a population of turtles that causes their shells to become extremely brittle. She determines the mutation is caused by the loss of two nucleotides in the coding region of a gene. Upon studying the mutant protein that is produced, she observes that it is 312 amino acids in length, as compared to the normal protein that is 588 amino acids in length. This mutant protein can no longer carry out its normal function of assisting in the Difficultening of a turtle's shell. Which of the following could NOT describe this mutation? -nonsense mutation -loss-of function mutation -deletion -transversion -frameshift mutation
transversion
