Chapter 16

Question 1

Researches who showed that DNA is the genetic material of a phage

Answer 1

Alfred Hershey and Martha Chase

Question 2

Hershey and Chase experiment

Answer 2

An experiment showing that only the DNA of the T2 phage enters an E coli cell during infection, and the injected DNA of the phage provides the genetic information

Question 3

DNA

Answer 3

A polymer of nucleotides each consisting of a nitrogenous base, a sugar, and a phosphate group

Question 4

bacteriophages

Answer 4

bacteria eaters

Question 5

antiparallel

Answer 5

subunits run in opposite directions

Question 6

nitrogenous bases

Answer 6

adenine, thymine, guanine, cytosine

Question 7

helicases

Answer 7

enzymes that untwist the double helix at the replication forks

Question 8

single strand binding proteins

Answer 8

bind to the unpaired DNA strands, keeping them from re-pairing

Question 9

Topoisomerase

Answer 9

an enzyme that helps relieve this strain by breaking, swiveling, and rejoining DNA strands

Question 10

primase

Answer 10

synthesizes RNA primers, using the parental DNA as a template

Question 11

RNA primer

Answer 11

a short stretch of RNA that is produced during the first stages of DNA synthesis

Question 12

DNA polymerases

Answer 12

catalyze the synthesis of new DNA by adding nucleotides to the 3 prime end of a preexisting chain

Question 13

leading strand

Answer 13

DNA that is created in the 5 prime to 3 prime direction, nucleotides are continuously added to the new complementary strand, only one primer is needed

Question 14

lagging strand

Answer 14

DNA elongated to the 3 prime to 5 prime direction, synthesized discontinuously in a series of Okazaki fragments

Question 15

Okazaki fragments

Answer 15

segments created in a lagging strand, each fragment is primed separately

Question 16

DNA ligase

Answer 16

“glues” Okazaki fragments into a continuous strand

Question 17

mismatch repair

Answer 17

other enzymes remove and replace incorrectly paired nucleotides that have resulted from replication errors

Question 18

nucleotide excision repair

Answer 18

enzymes detect and repair damaged DNA, nuclease enzyme cuts at the damaged DNA strand and then removes it, repair synthesis by DNA polymerase occurs, DNA ligase seals the ends

Question 19

telomeres

Answer 19

the DNA consists of multiple repetitions of one short nucleotide sequence, located at the ends of DNA

Question 20

chromatin

Answer 20

complex of DNA and protein

Question 21

histones

Answer 21

responsible for the first level of DNA packing in chromatin

Question 22

heterochromatin

Answer 22

interphase chromatin visible as irregular clumps, very condensed together

Question 23

euchromatin (true chromatin)

Answer 23

less condensed, more dispersed, its DNA is accessible for transcribing genetic information