exam 5 study

Question 1

DNA is synthesized through a process known as

Answer 1

Semi-conservative replication

Question 2

what catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed

Answer 2

DNA polymerase

Question 3

continuous replication

Answer 3

leading strand
primase
RNA primer
DNA helicase

Question 4

discontinuous replication

Answer 4

single strand binding protein
lagging strand
okazaki fragments
DNA ligase
primase
RNA primer
DNA helicase

Question 5

difference between the leading and lagging strand

Answer 5

The leading strand is synthesized continuously in the
5’ → 3’ direction.
The leading strand is synthesized in the same direction as the movement of the replication fork.

The lagging strand is synthesized discontinuously in the
5’ → 3’ direction.
The lagging strand is synthesized in the opposite direction

Question 6

major difference between eukaryotic DNA replication and prokaryotic DNA replication

Answer 6

Prokaryotic chromosomes have a single origin of replication, while eukaryotic chromosomes have multiple origins of replication.

Question 7

what is a telomere

Answer 7

the ends of linear chromosomes.
made from DNA sequences and protein

Question 8

How might adding telomerase affect cellular aging

Answer 8

Telomerase eliminates telomere shortening and retards aging

Question 9

which of the following cells have reduced or very little active telomerase activity

Answer 9

most normal somatic cells

Question 10

if a cell were unable to produce histone proteins, which of the following would be a likely effect

Answer 10

the cell’s DNA couldn’t be packed into its nucleus

Question 11

which of the following statements describe a eukaryotic chromosome

Answer 11

a single linear molecule of double-stranded DNA plus proteins

Question 12

which of the following statements describes chromatin?

Answer 12

Heterochromatin is highly condensed, whereas euchromatin is less compact

Question 13

which of the following is most critical for the association between histones and DNA

Answer 13

Histones are positively charged and DNA is negatively charged.

Question 14

A new DNA strand elongates only in the 5’ to 3’ direction because

Answer 14

DNA polymerase can add nucleotides only to the free 3’ end

Question 15

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Answer 15

It joins Okazaki fragments together

Question 16

What is meant by the description “antiparallel” regarding the strands that make up DNA?

Answer 16

The 5’ to 3’ direction of one strand runs counter to the 5’ to 3’ direction of the other strand.

Question 17

Which of the following would you expect of a eukaryote lacking telomerase?

Answer 17

a reduction in chromosome length in gametes

Question 18

Helicase

Answer 18

binds at replication fork, breaks H-bonds between bases
separates the DNA strands during replication

Question 19

What is the function of topoisomerase?

Answer 19

Relieving strain in the DNA ahead of the replication fork
binds ahead of the replication fork, breaks covalent bonds in DNA backbone

Question 20

Primase

Answer 20

synthesizes short segments of RNA

Question 21

In a nucleosome, the DNA is wrapped around

Answer 21

histones

Question 22

RNA primers

Answer 22

Sequence of RNA primers bound to a region of single-stranded DNA to initiate DNA replication.

RNA primer and DNA are covalently attached by a phosphodiester linkage.

Question 23

DNA polymerase III

Answer 23

catalyzes the elongation of a DNA strand in the 5’ → 3’ direction

Question 24

single strand binding protein

Answer 24

hold the DNA strands apart while they are being replicated

binds after the replication fork, prevents H-bonds between bases

Question 25

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?

Answer 25

The cell can be transformed to a cancerous cell.

Question 26

Recombiant DNA

Answer 26

genetic engineering that recombines DNA molecules from two or more different sources into a single molecule