chapter 16 DNA replication

DNA polymerase adds nucleotides to the __________ of the leading strands, and to the __________ of the lagging strands (Okazaki fragments). ( Concept 16.2) 5′ end ... 5′ end 3′ end ... 5′ end 3′ end ... 3′ end sugar group ... phosphate group 5′ end ... 3′ end

3′ end ... 3′ end

Which of the following statements about replication origins is/are correct? ( Concept 16.2) Replication proceeds in both directions from each origin. The DNA sequence at the origin of replication is recognized by specific proteins that bind to the origin. Bacterial chromosomes have a single origin of replication, but eukaryotic chromosomes have many origins. The two strands of DNA at the origin of replication are separated, creating a replication bubble. All of the listed responses are correct.

All of the listed responses are correct.

What is the major difference between bacterial chromosomes and eukaryotic chromosomes? ( Concept 16.3) There is no difference between bacterial and eukaryotic chromosomes. The DNA molecules of bacterial chromosomes have a slightly different structure than those of eukaryotic chromosomes. Bacterial chromosomes have much more protein associated with the DNA than eukaryotes. Bacteria usually have a single circular chromosome whereas eukaryotes have several linear chromosomes. Eukaryotes have a single circular chromosome whereas bacteria have several linear chromosomes.

Bacteria usually have a single circular chromosome whereas eukaryotes have several linear chromosomes.

What enzyme joins Okazaki fragments? ( Concept 16.2) helicase DNA polymerase primase topoisomerase DNA ligase

DNA ligase

The removal of the RNA primer and addition of DNA nucleotides to the 3' end of Okazaki fragments in its place is carried out by __________. ( Concept 16.2) DNA polymerase I nuclease DNA polymerase III primase ligase

DNA polymerase I

Which one of the following statements regarding DNA replication is correct? ( Concept 16.2) The two strands separate, and each one receives a complementary strand of RNA. Then this RNA serves as a template for the assembly of many new strands of DNA. Helicases separate the two strands of the double helix, and DNA polymerases then construct two new strands using each of the original strands as templates. Ligase separates the two strands of the DNA double helix. Then, DNA polymerase synthesizes the leading strand and primase synthesizes the lagging strand. Ligase assembles nucleotides into Okazaki fragments. Then polymerase joins these fragments together into a DNA strand. The two strands of DNA separate, and nuclease enzymes digest one strand. Then, DNA polymerase synthesizes two new strands out of the old ones.

Helicases separate the two strands of the double helix, and DNA polymerases then construct two new strands using each of the original strands as templates.

Which of the following components is required for DNA replication? ( Concept 16.2) RNA primer proteases ribosomes sucrases messenger RNA

RNA primer

Once the DNA at the replication fork is unwound by helicases, what prevents the two strands from coming back together to re-form a double helix? ( Concept 16.2) Single-strand binding proteins bind the unwound DNA and prevent the double helix from re-forming. The helicase modifies the DNA in such a way as to eliminate the affinity between the two strands. The helicase pushes the two strands so far apart that they have no chance of finding each other. DNA polymerase follows the helicase so closely that there is no chance for the strands to come back together. One of the strands is rapidly degraded, preventing the double helix from re-forming.

Single-strand binding proteins bind the unwound DNA and prevent the double helix from re-forming.

One strand of a DNA molecule has the base sequence 5′-ATAGGT-3′. The complementary base sequence on the other strand of DNA will be 3′- __________-5′. ( Concept 16.2) TATCCA ATAGGT TGGAUA UAUCCA TGGATA

TATCCA

At each end of a DNA replication bubble is __________. ( Concept 16.2) a telomere an origin of replication a gene a replication fork a ribosome

a replication fork

In DNA, the two purines are __________, and the two pyrimidines are __________. ( Concept 16.1) cytosine and thymine ... adenine and guanine cytosine and guanine ... adenine and thymine adenine and thymine ... cytosine and guanine adenine and cytosine ... guanine and thymine adenine and guanine ... cytosine and thymine

adenine and guanine ... cytosine and thymine

The role of DNA polymerases in DNA replication is to __________. ( Concept 16.2) synthesize an RNA primer to initiate DNA strand synthesis separate the two strands of DNA attach free nucleotides to the new DNA strand link together short strands of DNA All of the listed responses are correct.

attach free nucleotides to the new DNA strand

During the replication of DNA, __________. ( Concept 16.2) errors never occur the cell undergoes mitosis only one strand of the molecule acts as a template the reaction is catalyzed by RNA polymerase both strands of a molecule act as templates

both strands of a molecule act as templates

The incorporation of an incorrect base into the DNA during replication __________. ( Concept 16.2) cannot be repaired, and a new mutation will invariably result is virtually impossible, as the accuracy of DNA polymerase is such that errors almost never occur will trigger the cell to destroy the new strand, and replication will begin again can be repaired by the mismatch repair system will almost certainly lead to the death of the cell

can be repaired by the mismatch repair system

Telomeres __________. ( Concept 16.2) are shorter for younger individuals get longer with each round of DNA replication get shorter with each round of DNA replication remain the same regardless of the frequency of DNA replication are found in both prokaryotic and eukaryotic cells

get shorter with each round of DNA replication

After the formation of a replication bubble, which of the following is the correct sequence of enzymes used for the synthesis of the lagging DNA strand? ( Concept 16.2) primase, helicase, DNA polymerase, ligase helicase, DNA polymerase, primase, ligase ligase, primase, DNA polymerase, helicase helicase, primase, DNA polymerase, ligase helicase, primase, ligase, DNA polymerase

helicase, DNA polymerase, primase, ligase

The two antiparallel strands of nucleotides that form the DNA double helix are held together by __________. ( Concept 16.1) 5' deoxyribose and phosphate bonds ionic bonds between guanine and cytosine covalent bonds between nitrogen atoms in adenine and in thymine covalent bonds between carbon atoms in deoxyribose molecules hydrogen bonds between nucleotide bases

hydrogen bonds between nucleotide bases

Telomerase __________. ( Concept 16.2) splits telomeres prevents the loss of centromeric DNA is an enzyme that lengthens telomeres slows the rate of cancer cell growth speeds cell aging

is an enzyme that lengthens telomeres

Which of the following attributes of DNA is most crucial to its accurate duplication? ( Concept 16.2) its helical nature and hydrogen bonding its specific sequence of bases its deoxyribose sugar and phosphate groups its phosphodiester linkages and complementary strands its specific base pairing through hydrogen bonds

its specific base pairing through hydrogen bonds

In prokaryotes, the rate of elongation during DNA replication is __________ the rate in eukaryotes. ( Concept 16.2) much faster than The rates are not comparable, because elongation only occurs in prokaryotes. sometimes faster and sometimes slower than much slower than about the same as

much faster than

Which set of enzymes is involved in nucleotide excision repair? ( Concept 16.2) nuclease, DNA polymerase, primase DNA polymerase, helicase, primase ligase, nuclease, and primase nuclease, DNA polymerase, and ligase hydrolase, nuclease, and ligase

nuclease, DNA polymerase, and ligase

Monomers for the synthesis of DNA are called __________. ( Concept 16.1) monosaccharides nucleotides amino acids disaccharides fatty acids

nucleotides

The two strands of a DNA double helix are antiparallel. This means that __________. ( Concept 16.2) only one of the two strands can be used as a template for replication, because DNA polymerase only works in one direction the two strands are mirror images they both run in the 3' to 5' direction one strand is actually composed of RNA one strand runs in the 5' to 3' direction, and the other runs in the 3' to 5' direction

one strand runs in the 5' to 3' direction, and the other runs in the 3' to 5' direction

The information in DNA is contained in __________. ( Concept 16.1) the sequence of amino acids that makes up the DNA molecule the sequence of nucleotides along the length of the two strands of the DNA molecule the types of sugars used in making the DNA molecule the variation in the structure of nucleotides that make up the DNA molecule All of the listed responses are correct.

the sequence of nucleotides along the length of the two strands of the DNA molecule

The unwinding of DNA at the replication fork causes twisting and strain in the DNA ahead of the fork, which is relieved by an enzyme called __________. ( Concept 16.2) topoisomerase ligase helicase primase relievase

topoisomerase