AP Bio Chapter 13 Study Questions

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? A) 8% B) 16% C) 42% D) 31% E) It cannot be determined from the information provided.

A

In a nucleosome, the DNA is wrapped around A) histones. B) satellite DNA. C) ribosomes. D) polymerase molecules. E) a thymine dimer.

A

Replication in prokaryotes differs from replication in eukaryotes for which of the following reasons? A) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. B) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. C) Prokaryotes have telomeres, and eukaryotes do not. D) Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not. E) The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes.

A

Studies of nucleosomes have shown that histones (except H1) exist in each nucleosome as two kinds of tetramers: one of 2 H2A molecules and 2 H2B molecules, and the other as 2 H3 and 2 H4 molecules. Which of the following is supported by this data? A) The two types of tetramers associate to form an octamer. B) DNA has to associate with individual histones before they form tetramers. C) The structure of H3 and H4 molecules is not basic like that of the other histones. D) DNA can wind itself around either of the two kinds of tetramers. E) Only H2A can form associations with DNA molecules.

A

The reason for using Taq polymerase for PCR is that A) it is heat stable and can withstand the heating step of PCR. B) it has regions that are complementary to the primers. C) it binds more readily than other polymerases to the primers. D) it is heat stable, and it binds more readily than other polymerases to the primers. E) only minute amounts are needed for each cycle of PCR.

A

To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act? A) endonuclease, DNA polymerase I, DNA ligase B) helicase, DNA polymerase I, DNA ligase C) DNA ligase, nuclease, helicase D) DNA polymerase I, DNA polymerase III, DNA ligase E) exonuclease, DNA polymerase III, RNA primase

A

Use Figure 13.3 to answer the following question. Which enzyme was used to produce the molecule in Figure 13.3? A) a restriction enzyme B) transcriptase C) DNA polymerase D) RNA polymerase E) ligase

A

Use the following information to answer the next few questions. A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria that do not take up any plasmids would grow on which media? A) the nutrient broth only B) the nutrient broth and the ampicillin broth C) all three broths D) the nutrient broth and the tetracycline broth E) the tetracycline broth and the ampicillin broth

A

Use the list of choices below for the following questions: I. helicase II. DNA polymerase III III. ligase IV. DNA polymerase I V. primase Which of the enzymes separates the DNA strands during replication? A) I B) II C) III D) IV E) V

A

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? A) It joins Okazaki fragments together. B) It catalyzes the lengthening of telomeres. C) It synthesizes RNA nucleotides to make a primer. D) It unwinds the parental double helix. E) It stabilizes the unwound parental DNA.

A

A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in ¹⁵N medium for several generations and then transfer them to ¹⁴N medium. Which pattern in Figure 13.1 would you expect if the DNA was replicated in a conservative manner? A) A B) B C) C D) D E) E

B

After mixing a heat-killed, phosphorescent (light-emitting) strain of bacteria with a living, nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observation(s) would provide the best evidence that the ability to phosphoresce is a heritable trait? A) Both DNA and protein passed from the heat-killed strain to the living strain. B) Descendants of the living cells are also phosphorescent. C) The phosphorescence in the living strain is especially bright. D) DNA passed from the heat-killed strain to the living strain. E) Protein passed from the heat-killed strain to the living strain.

B

If a cell were unable to produce histone proteins, which of the following would be a likely effect? A) There would be an increase in the amount of "satellite" DNA produced during centrifugation. B) The cell's DNA couldn't be packed into its nucleus. C) Spindle fibers would not form during prophase. D) Amplification of other genes would compensate for the lack of histones. E) Pseudogenes would be transcribed to compensate for the decreased protein in the cell.

B

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts? A) DNA contains purines, whereas protein includes pyrimidines. B) DNA contains phosphorus, whereas protein does not. C) DNA contains sulfur, whereas protein does not. D) RNA includes ribose, whereas DNA includes deoxyribose sugars. E) DNA contains nitrogen, whereas protein does not.

B

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells are impaired in what way? A) They cannot replicate DNA. B) They cannot repair thymine dimers. C) They cannot undergo mitosis. D) They do not recombine homologous chromosomes during meiosis. E) They cannot exchange DNA with other cells.

B

Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise? A) replication followed by mitosis B) replication without separation C) fertilization by multiple sperm D) special association with histone proteins E) meiosis followed by mitosis

B

The leading and the lagging strands differ in that A) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together. B) 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. C) the leading strand is synthesized at twice the rate of the lagging strand. D) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end.

B

Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction? A) helicase B) DNA polymerase III C) topoisomerase D) DNA ligase E) primase

B

Which of the following investigators was (were) responsible for the following discovery? In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine. A) Matthew Meselson and Franklin Stahl B) Erwin Chargaff C) Alfred Hershey and Martha Chase D) Frederick Griffith E) Oswald Avery, Maclyn McCarty, and Colin MacLeod

B

Why is it so important to be able to amplify DNA fragments when studying genes? A) DNA fragments are too small to use individually. B) A gene may represent only a millionth of the cell's DNA. C) A clone requires multiple copies of each gene per clone. D) It is important to have multiple copies of DNA in the case of laboratory error. E) Restriction enzymes cut DNA into fragments that are too small.

B

You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent A) lagging strands and Okazaki fragments. B) leading strands and Okazaki fragments. C) RNA primers and mitochondrial DNA. D) leading strands and RNA primers. E) Okazaki fragments and RNA primers.

B

Given the damage caused by UV radiation, the kind of gene affected in those with XP is one whose product is involved with A) mending of double-strand breaks in the DNA backbone. B) the removal of double-strand damaged areas. C) the ability to excise single-strand damage and replace it. D) breakage of cross-strand covalent bonds. E) causing affected skin cells to undergo apoptosis.

C

How do we describe transformation in bacteria? A) the creation of a strand of RNA from a DNA molecule B) the type of semiconservative replication shown by DNA C) assimilation of external DNA into a cell D) the creation of a strand of DNA from an RNA molecule E) the infection of cells by a phage DNA molecule

C

In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding? A) the metaphase chromosome B) DNA without attached histones C) the 30-nm chromatin fiber D) DNA with H1 only E) the 10-nm chromatin fiber

C

In an analysis of the nucleotide composition of DNA, which of the following will be found? A) A = G and C = T B) G + C = T + A C) A + C = G + T D) A = C

C

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules? A) G = T B) A = G C) A + G = C + T D) A = C E) A + T = G + T

C

In his work with pneumonia-causing bacteria and mice, Griffith found that A) bacteriophages injected DNA into bacteria. B) heat-killed pathogenic cells caused pneumonia. C) some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic. D) the protein coat from pathogenic cells was able to transform nonpathogenic cells. E) the polysaccharide coat of bacteria caused pneumonia.

C

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? A) One of the daughter cells, but not the other, would have radioactive DNA. B) Neither of the two daughter cells would be radioactive. C) DNA in both daughter cells would be radioactive. D) All four bases of the DNA would be radioactive. E) Radioactive thymine would pair with nonradioactive guanine.

C

The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that A) ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. B) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups. C) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. D) triphosphate monomers are active in the nucleoside triphosphates, but not in ATP. E) ATP contains three high-energy bonds; the nucleoside triphosphates have two.

C

The elongation of the leading strand during DNA synthesis A) progresses away from the replication fork. B) occurs in the 3' → 5' direction. C) depends on the action of DNA polymerase. D) does not require a template strand. E) produces Okazaki fragments.

C

The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage? A) topoisomerase, primase, DNA polymerase B) topoisomerase, helicase, single-strand binding protein C) nuclease, DNA polymerase, DNA ligase D) nuclease, topoisomerase, primase E) DNA ligase, replication fork proteins, adenylyl cyclase

C

Use the following information to answer the next few questions. A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest. Why might they be conducting such an experiment? A) to find the location of this gene in the human genome B) to collect population data that can be used to assess natural selection C) to find which of the students has which alleles D) to collect population data that can be used to study genetic drift E) to prepare to isolate the chromosome on which the gene of interest is found

C

Use the list of choices below for the following questions: I. helicase II. DNA polymerase III III. ligase IV. DNA polymerase I V. primase Which of the enzymes covalently connects segments of DNA? A) I B) II C) III D) IV E) V

C

What is meant by the description "antiparallel" regarding the strands that make up DNA? A) Base pairings create unequal spacing between the two DNA strands. B) One strand is positively charged and the other is negatively charged. C) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. D) The twisting nature of DNA creates nonparallel strands. E) One strand contains only purines and the other contains only pyrimidines.

C

Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA? A) the sequence of nucleotides B) the rate of replication C) the diameter of the helix D)the bond angles of the subunits E) the frequency of A vs. T nucleotides

C

Which of the following modifications is least likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? A) acetylating the cytosine bases within the DNA fragment B) decreasing the length of the DNA fragment C) altering the nucleotide sequence of the DNA fragment without adding or removing nucleotides D) neutralizing the negative charges within the DNA fragment E) increasing the length of the DNA fragment

C

Which of the following sets of materials is required by both eukaryotes and prokaryotes for replication? A) G-C rich regions, polymerases, chromosome nicks B) ligase, primers, nucleases C) double-stranded DNA, four kinds of dNTPs, primers, origins of replication D) topoisomerases, telomerases, polymerases E) nucleosome loosening, four dNTPs, four rNTPs

C

Which of the following statements describes the eukaryotic chromosome? A) The nucleosome is its most basic functional subunit. B) The number of genes on each chromosome is different in different cell types of an organism. C) It consists of a single linear molecule of double-stranded DNA plus proteins. D) Active transcription occurs on heterochromatin but not euchromatin. E) It is composed of DNA alone.

C

Why do histones bind tightly to DNA? A) Histones are highly hydrophobic, and DNA is hydrophilic. B) Histones are covalently linked to the DNA. C) Histones are positively charged, and DNA is negatively charged. D) Histones are negatively charged, and DNA is positively charged. E) Both histones and DNA are strongly hydrophobic.

C

A new DNA strand elongates only in the 5' to 3' direction because A) Okazaki fragments prevent elongation in the 3' to 5' direction. B) the polarity of the DNA molecule prevents addition of nucleotides at the 3' end. C) DNA polymerase begins adding nucleotides at the 5' end of the template. D) DNA polymerase can only add nucleotides to the free 3' end. E) replication must progress toward the replication fork.

D

An Okazaki fragment has which of the following arrangements? A) primase, polymerase, ligase B) DNA polymerase I, DNA polymerase III C) 5' DNA to 3' D) 5' RNA nucleotides, DNA nucleotides 3' E) 3' RNA nucleotides, DNA nucleotides 5'

D

Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to A) cut the plasmid with restriction enzyme X and insert the fragments cut with restriction enzyme Y into the plasmid. B) cut the plasmid with restriction enzyme X and then insert the gene into the plasmid. C) insert the fragments cut with restriction enzyme X directly into the plasmid without cutting the plasmid. D) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme. E) cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X.

D

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 T͟ G C A A T C C 5' An RNA primer is formed starting at the underlined T (T͟ ) of the template. Which of the following represents the primer sequence? A) 5' G C C T A G G 3' B) 5' A C G T T A G G 3' C) 5' G C C U A G G 3' D) 5' A C G U U A G G 3' E) 3' G C C T A G G 5'

D

In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation? A) Replication will require a DNA template from another source. B) The DNA will supercoil. C) Replication will occur via RNA polymerase alone. D) No replication fork will be formed. E) No proofreading will occur.

D

In an experiment, DNA is allowed to replicate in an environment with all necessary enzymes, dATP, dCTP, dGTP, and radioactively labeled dTTP (³ H thymidine). After several minutes, the DNA is switched to nonradioactive medium and is then viewed by electron microscopy and autoradiography. Figure 13.2 represents the results. It shows a replication bubble, and the dots represent radioactive material. Which of the following is the most likely interpretation of the results? A) Thymidine is being added only where the DNA strands are farthest apart. B) Replication proceeds in one direction only. C) Thymidine is being added only at the very beginning of replication. D) There are two replication forks going in opposite directions.

D

In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen (¹⁵N) and then transferred them to a medium containing ¹⁴N. Which of the results in Figure 13.1 would be expected after one round of DNA replication in the presence of ¹⁴N? A) A B) B C) C D) D E) E

D

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following? A) complementary pairing of bases B) phosphate—sugar backbones C) different five-carbon sugars D) sequence of bases E) side groups of nitrogenous bases

D

Once the pattern found after one round of replication was observed, Meselson and Stahl could be confident of which of the following conclusions? A) Replication is not semi-conservative. B) Replication is neither dispersive nor conservative. C) Replication is not dispersive. D) Replication is not conservative. E) Replication is semi-conservative.

D

Use the following information to answer the next few questions. A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria that contain the plasmid, but not the eukaryotic gene, would grow A) only in the broth containing both antibiotics. B) in the broth containing tetracycline, but not in the broth containing ampicillin. C) in the nutrient broth without antibiotics only. D) in all four types of broth. E) in the nutrient broth plus ampicillin, but not in the broth containing tetracycline.

D

Use the following information to answer the next few questions. A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest. Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate? A) Each pair of students has a different gene for this function. B) Each of these students is heterozygous for this gene. C) The students with three fragments are said to have "fragile sites." D) The two students who have two fragments have one restriction site in this region. E) The two students who have two fragments have two restriction sites within this gene.

D

Use the list of choices below for the following questions: I. helicase II. DNA polymerase III III. ligase IV. DNA polymerase I V. primase Which of the enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments? A) I B) II C) III D) IV E) V

D

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? A) DNA ligase works only in the 3' → 5' direction. B) The origins of replication occur only at the 5' end. C) Polymerase can work on only one strand at a time. D) DNA polymerase can join new nucleotides only to the 3' end of a growing strand. E) Helicases and single-strand binding proteins work at the 5' end.

D

What is the function of topoisomerase? A) stabilizing single-stranded DNA at the replication fork B) elongating new DNA at a replication fork by adding nucleotides to the existing chain C) adding methyl groups to bases of DNA D) relieving strain in the DNA ahead of the replication fork E) unwinding of the double helix

D

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with a recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes. III. Extract plasmid DNA from bacterial cells. IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. V. Use ligase to seal plasmid DNA to nonplasmid DNA. A) IV, V, I, II, III B) II, III, V, IV, I C) I, II, IV, III, V D) III, II, IV, V, I E) III, IV, V, I, II

D

Which of the following represents the order of increasingly higher levels of organization of chromatin? A) looped domain, 30-nm chromatin fiber, nucleosome B) 30-nm chromatin fiber, nucleosome, looped domain C) nucleosome, looped domain, 30-nm chromatin fiber D) nucleosome, 30-nm chromatin fiber, looped domain E) looped domain, nucleosome, 30-nm chromatin fiber

D

Which of the following statements is true of histones? A) The mass of histone in chromatin is approximately nine times the mass of DNA. B) Each nucleosome consists of two molecules of histone H1. C) Histones are found in mammals, but not in other animals or in plants or fungi. D) Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together. E) The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail."

D

A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? A) Okazaki fragments B) nucleotides C) primase D) DNA polymerase E) DNA ligase`

E

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? A) one high-density and one intermediate-density band B) one intermediate-density band C) one high-density and one low-density band D) one low-density band E) one low-density and one intermediate-density band

E

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? A) Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long. B) There is no radioactive isotope of nitrogen. C) Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive. D) Avery et al. have already concluded that this experiment showed inconclusive results. E) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

E

How does a bacterial cell protect its own DNA from restriction enzymes? A) by reinforcing the bacterial DNA structure with covalent phosphodiester bonds B) by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching C) by adding histones to protect the double-stranded DNA D) by using DNA ligase to seal the bacterial DNA into a closed circle E) by adding methyl groups to adenines and cytosines

E

In his transformation experiments, what did Griffith observe? A) Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic. B) Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. C) Mice infected with a pathogenic strain of bacteria can spread the infection to other mice. D) Mutant mice were resistant to bacterial infections. E) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

E

Use Figure 13.4 to answer the following question. The segment of DNA shown in Figure 13.4 has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?

E

Use the following information to answer the next few questions. A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow A) in the nutrient broth and the tetracycline broth only. B) in the nutrient broth only. C) in the nutrient broth, the ampicillin broth, and the tetracycline broth. D) in all four types of broth. E) in the ampicillin broth and the nutrient broth.

E

Use the list of choices below for the following questions: I. helicase II. DNA polymerase III III. ligase IV. DNA polymerase I V. primase Which of the enzymes synthesizes short segments of RNA? A) I B) II C) III D) IV E) V

E

What is the function of DNA polymerase III? A) to degrade damaged DNA molecules B) to seal together the broken ends of DNA strands C) to rejoin the two DNA strands (one new and one old) after replication D) to unwind the DNA helix during replication E) to add nucleotides to the 3' end of a growing DNA strand

E

Which of the following help(s) to hold the DNA strands apart while they are being replicated? A) DNA polymerase B) ligase C) exonuclease D) primase E) single-strand binding proteins

E

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme A) AAGG TTCC B) AGTC TCAG C) AAAA TTTT D) ACCA TGGT E) GGCC CCGG

E

Which of the following statements describes chromatin? A) Only euchromatin is visible under the light microscope. B) Euchromatin is not transcribed, whereas heterochromatin is transcribed. C) Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA. D) Both heterochromatin and euchromatin are found in the cytoplasm. E) Heterochromatin is highly condensed, whereas euchromatin is less compact.

E