BIOLOGY EXAM 3
A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is ________.
AAA
Allolactose, an isomer of lactose, is formed in small amounts from lactose. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when lactose enters the cell?
Allolactose binds to the repressor protein.
For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?
Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
In meiosis, homologous chromosomes are separated durinf
Anaphase I
In meiosis, homologous chromosomes are separated during
Anaphase I
What phase of meiosis is seen in the figure?
Anaphase I
Centromeres split and sister chromatids migrate to opposite poles in_____ of meiosis
Anaphase II
The proteome is all the proteins produced by an organism. The genome is the totality of all genes of an organism. If the proteome is much larger than the genome, which of the following statements would be accurate?
At least in some cases, a single gene must code for more than one protein.
Which of these statements is correct
At sexual maturity, ovaries and testes produce haploid gametes by meiosis.
Refer to the associated figure. In the branched metabolic pathway indicated in the figure, if enzyme 3 is defective and the amount of each enzyme is constant, you might expect to see an increase in the amount of which intermediate or product?
B
Put the following events of elongation in prokaryotic translation in chronological order. 1.Binding of mRNA with small ribosomal subunit 2.Recognition of initiation codon 3.Complementary base pairing between initiator codon and anticodon of initiator tRNA 4.Base pairing of the mRNA codon following the initiator codon with its complementary tRNA 5.Attachment of the large subunit
1, 2, 3, 5, 4
How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2n=8)
16
The diploid number of a roundworm species is 4. Assuming there is no crossover, and random segregation of homologous during meiosis, how many different possible combinations of chromosomes might there be in the offspring?
16
Put the following steps of DNA replication in chronological order. 1.Single-stranded binding proteins attach to DNA strands. 2.Hydrogen bonds between base pairs of antiparallel strands are broken. 3.Primase binds to the site of origin. 4.DNA polymerase binds to the template strand. 5.An RNA primer is created.
2, 1, 3, 5, 4
In the snail pomacea Paula catemacwnsis n=13. What is the diploid number for this organism
26
The following question(s) refer to this table of codons.A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe-leu-ile-val would be ________.
3' AAA-GAA-TAA-CAA 5'
Use the following information to answer the question below.A part of an mRNA molecule with the following sequence is being read by a ribosome: 5' CCG-ACG 3'(mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form.The anticodon loop of the first tRNA that will complement this mRNA is: tRNA AnticodonAmino AcidGGCCGUUGCCCGACGCGGProlineAlanineThreonineGlycineCysteineAlanine
3' GGC 5'
A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is ________.
3' UCA 5'
Put the following events of bacterial transcription in chronological order. 1.Sigma binds to the promoter region. 2.The double helix of DNA is unwound, breaking hydrogen bonds between complementary strands. 3.Sigma binds to RNA polymerase. 4.Sigma is released. 5.Transcription begins.
3, 1, 2, 5, 4
Quacking aspen can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happens, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
38
At a specific area of a chromosome, the following sequence of nucleotides is present where the chain opens to form a replication fork:3' C C T A G G C T G C A A T C C 5'An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?
5' A C G U U A G G 3'
A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?
5' TTT-CCC-AAA-GGG-TTT-CCC
Use this model of a eukaryotic transcript to answer the following question(s).E = exon and I = intron5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3'Which components of the previous molecule will also be found in mRNA in the cytosol?
5' UTR E1 E2 E3 E4 UTR 3'
Which of the following, if missing, would usually prevent translation from starting in eukaryotes?
5' cap or AUG codon
If the sequence in the coding strand of DNA for a particular amino acid is 5'AGT3', then the anticodon on the corresponding tRNA would be ________.
5'ACU3'
The chromosome number of hexaploid wheat, triticum aestivum, can be represented as
6n
The egg of a fruit fly has 4 individual chromosomes. How many chromosomes are in a somatic cell of a fruit fly?
8
In an analysis of the nucleotide composition of DNA, which of the following will be found?
A + C = G + T
In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?
A + G = C + T
Which of the following observations may have resulted in the hypothesis that a codon is made up of three bases?
A codon of three bases in length, from four different bases, would code for a maximum of sixty-four different amino acids.
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A gene from an organism can theoretically be expressed by any other organism.
Which of the following contradicts the one-gene, one-enzyme hypothesis?
A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally.
During elongation, which site in the ribosome represents the location where a codon is being read?
A site
How does termination of translation take place?
A stop codon is reached.
Refer to the figure associated with this question. What bases will be added to the primer as DNA replication proceeds? The bases should appear in the new strand in the order that they will be added starting at the 3' end of the primer.
A, G, A, C, G, A, C
Use this information to answer the question(s) below.Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.If she moves the promoter for the lac operon to the region between the beta galactosidase (lacZ) gene and the permease (lacY) gene, which of the following would be likely?
Beta galactosidase will not be produced.
sexual reproduction
Can produce diverse phenotypes that may enhance survival of a population in a changing environment
Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare?
Codons are a nearly universal language among all organisms.
In the accompanying figure, which structure causes the two strands of DNA to separate?
D
Genotype is to ________ as phenotype is to ________.
DNA base sequence; physical traits that are products of the proteins produced
In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?
DNA contains phosphorus, whereas protein does not.
Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed?
DNA polymerase
Which of the following can occur by the process of meiosis but not mitosis
Diploid cells form haploid cells.
The karotype of one species of primate has 48 chromosomes. In a particular female cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following?
Either anaphase I or II
Refer to the figure associated with this question. Which structure is responsible for stabilizing DNA in its single-stranded form?
F
The somatic cells of a privet shrub each contain 46 chromosomes. How do privet chromosomes differ from the chromosomes of humans who also have 46?
Genes of privet chromosomes are significantly different than those in humans.
Which of the following happens at the conclusion of meiosis I
Homologous chromosomes of a pair are separated from each other.
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together.
Why might a point mutation in DNA make a difference in the level of a protein's activity? Group of answer choices
It might substitute a different amino acid in the active site.
Crossing over normally takes place during which of the following processes?
Meiosis I
Independent assortment of chromosomes occurs durinf
Meiosis I only
Who performed classic experiments that supported the semiconservative model of DNA replication?
Meselson and Stahl
Once researchers identified DNA as the unit of inheritance, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. What is the mechanism of information transfer in eukaryotes?
Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place.
What does it mean when we say the genetic code is redundant?
More than one codon can specify the addition of the same amino acid.
There is a group of invertebrate animals called rotifers, among which a particular group of species reproduces, as far as is known, only asexually. These rotifers, however, have survived a long evolutionary history without evidence of having been overcome by excessive mutations. Since the to tigers develop from eggs, but asexually, what can you predict?
No fertile males can be found
When does dna replication take place with respect to meiosis dna replication
Occurs before meiosis I begins
What is responsible for termination of transcription in eukaryotic protein-coding genes?
a polyadenylation, or poly(A), signal
The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in ________.
a polypeptide missing an amino acid
Which of the following would you expect of a eukaryote lacking telomerase?
a reduction in chromosome length in gametes
In negative control, a gene is switched off when ________. Group of answer choices
a regulatory protein binds to DNA and shuts down transcription
Which of the following mutations is most likely to cause a phenotypic change?
a single nucleotide deletion in an exon coding for an active site
Which of the following mutations would be most likely to have a harmful effect on an organism?
a single nucleotide insertion downstream of, and close to, the start of the coding sequence
Which of the following nucleotide triplets best represents a codon?
a triplet in the same reading frame as an upstream AUG
Which of the following might result in a human zygote with 45 chromosomes?
an error in either egg or sperm meiotic anaphase
Suppose several genes are grouped together in a bacterial genome, transcribed together on a single mRNA, and the group results in a single enzyme. If one of these genes is mutated and the enzyme is no longer active, this gene must be part of ________.
an operon
Genetic mutations in asexually reproducing organisms lead to more evolutionary change than do genetic mutations in sexually reproducing ones because
asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations on to their offspring
If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following?
at most, 2 alleles for that gene
Which small-scale mutation would be most likely to have a catastrophic effect on the functioning of a protein?
base deletion near the start of a gene
Ribosomes can attach to prokaryotic messenger RNA ________.
before transcription is complete
David Pribnow studied the base sequences of promoters in bacteria and bacterial viruses. He found two conserved regions in these promoters (the −10 box and the −35 box). These two regions of the promoter ________.
bind the sigma subunit that is associated with RNA polymerase
Which of the following processes is central to the initiation of transcription in bacteria? Group of answer choices
binding of sigma to the promoter region
Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the ________.
binding of the anticodon to the codon and the attachment of amino acids to tRNAs
Imagine that you have set up a genetic screen to identify E. coli mutants that cannot metabolize the amino acid tryptophan for energy. Beginning with a master plate containing many colonies, you prepare replica plates on medium with glucose or tryptophan as the only energy source. You would look for colonies that ________.
can grow only on the plates with glucose
A compound known as X-gal is widely used in molecular genetic research. When wild-type (normal) E. coli is grown on medium containing X-gal, the bacterial colonies turn blue. In contrast, when lacZ mutants are grown on medium containing X-gal, the bacterial colonies remain their normal white color. X-gal is likely to be a compound ________.
chemically similar to lactose
The associated figure shows a diagram of blocks of genes on human chromosome 16 and the locations of blocks of similar genes on four chromosomes of the mouse.The movement of these blocks suggests that ________.
chromosomal translocations have moved blocks of sequences to other chromosomes
If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants?
cloning the plant
The anticodon of a particular tRNA molecule is ________. Group of answer choices
complementary to the corresponding mRNA codon
Which of the following occurs in prokaryotes but not in eukaryotes?
concurrent transcription and translation
For the duration of meiosis I, each chromosome _____.
consists of 2 sister chromatids joined by a centromere
For the duration of meiosis I, each chromosome _____.
consists of two sister chromatids joined by a centromere
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?
gaps left at the 5' end of the lagging strand
Which of the following characteristics, structures, or processes is common to bacteria and viruses?
genetic material composed of nucleic acid
What makes sexually reproduced offspring genetically different from their parents?
genetic recombination during meiosis
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
haploid, and the chromosomes are each composed of two chromatids
The greatest expression of the lac operon occurs when lactose levels are ________.
high and glucose levels are low
What type of bonding is responsible for maintaining the shape of the tRNA molecule shown in the figure above?
hydrogen bonding between base pairs
The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is TRUE?
if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only) in a different organism
Which of the following would be LEAST likely to cause DNA damage to an individual suffering from xeroderma pigmentosum (XP)?
incandescent lightbulbs
In comparing DNA replication with RNA transcription in the same eukaryotic cell, only DNA replication ________.
incorporates the entire template molecule in the product
In the first step of their experiments, Jacob and Monod treated E. coli cells with ultraviolet light or X-rays to ____
increase the frequency of mutations in all genes
In the first step of their experiments, Jacob and Monod treated E. coli cells with ultraviolet light or X-rays to ________.
increase the frequency of mutations in all genes
Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation?
inducer
Which of the following, when taken up by a cell, binds to a repressor so that the repressor no longer binds to the operator? (Hint: this is a general name for what lactose would be in regulation of the lac operon)
inducer
A nonsense mutation in a gene ________.
introduces a premature stop codon into the mRNA
A mutation that results in premature termination of translation ________.
is a nonsense mutation
The statement "DNA → RNA → Proteins" ________.
is known as central dogma
Which one of the following is TRUE? A codon ________.
is the basic unit of the genetic code
Which of the following would enable you to detect aneuploidy
karyotyping
Use this information to answer the question(s) below.Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.If she moves the repressor gene (lacI), along with its promoter, to a position at some several thousand base pairs away from its normal position, we would expect the ________.
lac operon will function normally
In a human karyotype chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common
length, centromere position, staining pattern, and traits coded for by their genes
In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosome of the pair have in common?
length, centromere position, staining pattern, and traits coded for by their genes
What is a major difference between mitosis and meiosis I in a diploid organism?
Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis I.
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have ________.
T4 protein and T4 DNA
Telomere shortening puts a limit on the number of times a cell can divide. Research has shown that telomerase can extend the life span of cultured human cells. How might adding telomerase affect cellular aging?
Telomerase eliminates telomere shortening and retards aging.
The tRNA shown with the previous question has its 3' end projecting beyond its 5' end. What will occur at this 3' end?
The amino acid binds covalently.
How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?
The base sequence of DNA carries the information needed to code for proteins.
In the Morse code, a series of dots and dashes code for letters of the alphabet. How is this analogous to the genetic code?
The bases of DNA code for the more complex amino acid sequence of the proteins in cells.
In a healthy cell, the rate of DNA repair is equal to the rate of DNA mutation. When the rate of repair lags behind the rate of mutation, what is a possible fate of the cell?
The cell can be transformed to a cancerous cell.
According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon?
The lac operon would be transcribed continuously.
A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?
The mother most likely underwent nondisjunction during gamete production.
Researchers found E. coli that had mutation rates 100 times higher than normal. Which of the following is the most likely cause of these results?
The proofreading mechanism of DNA polymerase was not working properly.
Use this information to answer the question(s) below.Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome.If she moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following would likely occur when the cell is exposed to lactose?
The structural genes will be transcribed continuously.
How are RNA hairpin turns related to transcriptional termination in E. coli?
The turns are formed from complementary base pairing and cause separation of the RNA transcript and RNA polymerase.
Which of the following statements is TRUE about protein synthesis in prokaryotes?
Translation can begin while transcription is still in progress.
Of the following, which is the most current description of a gene?
a DNA sequence that is expressed to form a functional product: either RNA or polypeptide
You want to engineer a eukaryotic gene into a bacterial colony and have it expressed. What must be included in addition to the coding exons of the gene?
a bacterial promoter sequence
Which of the following DNA mutations is most likely to damage the protein it specifies?
a base-pair deletion
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
a deletion of two nucleotides
According to the central dogma, what molecule should go in the blank? DNA → ________ → Proteins Group of answer choices
mRNA
Codons are part of the molecular structure of __
mRNA
Translation requires ________.
mRNA, tRNA, and rRNA
The following question(s) refer to this table of codons.What amino acid sequence will be generated, based on the following mRNA codon sequence?5' AUG-UCU-UCG-UUA-UCC-UUG 3'
met-ser-ser-leu-ser-leu
Homologous pairs of chromosomes align opposite to each other at the equator of a cell during
metaphase I of meiosis
Consider the following section of mRNA:UCUGAUGGGCUUU...Beginning with the start codon, which amino acids, in order, are coded for by this section of mRNA? Consult the codon table provided if necessary. Group of answer choices
methionine, glycine, phenylalanine
The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a ________. Group of answer choices
missense mutation
sister chromatids separate from each other during
mitosis and meiosis II
Plants produce more seeds when they reproduce asexually than sexually. Yet most plants reproduce sexually in nature. What is the probable explanation for the prevalence of sexual reproduction? Sexual reproduction _____.
mixes up alleles contributing to variation in a species
Which of the following cells have reduced or very little active telomerase activity?
most normal somatic cells
Point mutations are referred to as missense, silent, frameshift, or nonsense when they change the protein-coding potential of a gene. What is another group of mutations that may have important consequences for gene expression?
mutations that exist outside coding sequences
The product of the lacI gene functions most like a car's ________ in terms of its effect on transcription of the lac operon.
parking brake
Within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine and cytosine forms hydrogen bonds with guanine. This arrangement ________.
permits complementary base pairing
Refer to the figure associated with this question. The mRNA is smaller than the length of the DNA that codes for it because ________.
post-transcriptional modification removes the introns
Which of the following levels of gene expression allows the most rapid response to environmental change?
post-translational control
When we first see chiasmata under a microscope, we know that _____.
prophase I is occurring
A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that ________. Group of answer choices
proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU
Which of the following is a protein produced by a regulatory gene?
repressor
DNA is synthesized through a process known as ________.
semiconservative replication
In E. coli, if RNA polymerase is missing ________, then transcription initiation would not occur at the appropriate initiation sites.
sigma
Which of the following help(s) to hold the DNA strands apart while they are being replicated?
single-strand DNA binding proteins
Refer to the associated figure. A branched metabolic pathway synthesizes two related amino acids (D and F). If there is a genetic defect, resulting in a nonfunctional enzyme (3), how could you ensure that adequate amounts of the amino acid F are synthesized?
supplement with intermediate E
In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and ________ of the last nucleotide in the polymer.
the 3' OH
Given the damage caused by UV radiation, the kind of gene affected in those with XP is one whose product is involved with ________.
the ability to excise single-strand damage and replace it
What ensures that the correct amino acid is added during translation?
the anticodon of a properly formed aminoacyl tRNA
What provides the energy for the polymerization reactions in DNA synthesis?
the deoxyribonucleotide triphosphate substrates
Which of the following is an exception to the central dogma?
the discovery of RNA viruses that synthesize DNA using reverse transcriptase
According to the table and the figure associated with this question, which enzyme is defective in the strain with the arg2 mutation?
the enzyme that converts ornithine to citrulline
The leading and the lagging strands differ in that ________.
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction
There should be a strong positive correlation between the rate of protein synthesis and ________.
the number of ribosomes
Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?
the phosphate bonds in the nucleotide triphosphates that serve as substrates
Independent assortment of chromosomes is a result of
the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I
The product of the lacI gene is _______
the repressor
There are 61 mRNA codons that specify an amino acid, but only about 40 tRNAs. This is best explained by the fact that ________.
the rules for base pairing between the third base of a codon and tRNA are flexible
Which of the following is directly related to a single amino acid?
the three-base sequence of mRNA
In humans, xeroderma pigmentosum (XP) is a disorder of the nucleotide excision repair mechanism. These individuals are unable to repair DNA damage caused by ultraviolet light. Which of the following are the most prominent types of DNA lesions in individuals suffering from xeroderma pigmentosum?
thymine dimers
In E. coli, what is the function of DNA polymerase III?
to add nucleotides to the 3' end of a growing DNA strand
Knockout mice have been genetically altered to knock out specific genes. How are these mice most often used in research?
to determine the role of proteins coded for by those genes that are knocked out
Once a peptide bond has been formed between the amino acid attached to the tRNA in the P site and the amino acid associated with the tRNA in the A site, what occurs next? Group of answer choices
translocation
Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?
two
HIV, the causative agent of AIDS, is a retrovirus. A retrovirus ________.
uses reverse transcriptase to make DNA from RNA
As scientists were unraveling the mysteries associated with transcription and translation in eukaryotes, they discovered there was not a one-to-one correspondence between the nucleotide sequence of a gene and the base sequence of the mRNA it codes for. They proposed the genes-in-pieces hypothesis. How can the genes-in-pieces hypothesis be explained?
Introns are noncoding segments of DNA that are present in the initial transcript, but are removed by splicing.
In the figure associated with this question, what is the function of the ACC sequence at the 3' end?
It attaches to an amino acid.
In the figure associated with this question, what is the function of the AGU on the loop of the tRNA?
It base pairs with a codon of mRNA.
There is a mutation in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of these would characterize such a mutant?
It cannot bind to the inducer.
How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes?
It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity.
What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have multiple origins of replication.
In the process of transcription, _______
RNA is synthesized
The enzyme complex associated with DNA in the associated figure is ________.
RNA polymerase
A ribozyme is ________.
an RNA with catalytic activity
Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival by ________.
allowing an organism to adjust to changes in environmental conditions
An E. coli cell without a functional lacI gene is expected to ________.
always produce β-galactosidase
A frameshift mutation could result from ________.
either an insertion or a deletion of a base
Refer to the metabolic pathway illustrated in the associated figure. If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B would be able to grow on medium supplemented with ________.
nutrient C only
E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?
one low-density and one intermediate-density band
Semiconservative replication involves a template. What is the template?
one strand of the DNA molecule