CH 16

Question 1

DNA replication

Answer 1

-copying of DNA

Question 2

transformation

Answer 2

-a change in genotype and phenotype due to assimilation of foreign DNA

Question 3

bacteriophages (phages)

Answer 3

-viruses that infect bacteria

Question 4

virus

Answer 4

-DNA (sometimes RNA) enclosed by a protective coat, often simply protein

Question 5

double helix

Answer 5

-DNA
-twisted ladder

Question 6

antiparallel

Answer 6

-subunits run in opposite directions

Question 7

semiconservative model

Answer 7

-predicts that when a double helix replicates, each daughter molecule will have one old strand (derived from parent molecule) and one newly made strand

Question 8

origins of replication

Answer 8

-where the two DNA strands are separated
-short stretch of DNA that has a specific sequence of nucleotides

Question 9

replication fork

Answer 9

-a Y-shaped region where new DNA strands are elongating

Question 10

Helicases

Answer 10

-enzymes that untwist the double helix at the replication forks

Question 11

Single-strand binding proteins

Answer 11

-bind to and stabilize single-stranded DNA

Question 12

Topoisomerase

Answer 12

-relieves the strain of twisting of the double helix by breaking, swiveling, and rejoining DNA strands

Question 13

primer

Answer 13

-RNA chain
-initial nucleotide strand
-free 3’ end

Question 14

primase

Answer 14

-enzyme that joins RNA nucleotides to make a primer during DNA replication

Question 15

DNA polymerases

Answer 15

-catalyze the synthesis of new DNA at a replication fork

Question 16

leading strand

Answer 16

-moving toward the replication fork

Question 17

lagging strand

Answer 17

-moving away from the replication fork

Question 18

Okazaki fragments

Answer 18

segments synthesized by the lagging strand

Question 19

DNA ligase

Answer 19

-linking enzyme essential for DNA replication

Question 20

mismatch repair

Answer 20

-repair enzymes correct errors in base pairing

Question 21

nucleotide excision repair

Answer 21

-a nuclease cuts out and replaces damaged stretches of DNA

Question 22

nuclease

Answer 22

-DNA cutting enzyme

Question 23

telomeres

Answer 23

-special nucleotide sequences at the ends of Eukaryotic chromosomal DNA molecules

Question 24

chromatin

Answer 24

-complex of DNA and proteins

Question 25

histones

Answer 25

-responsible for the first level of packing in chromatin

Question 26

nucleosome

Answer 26

-basic unit of DNA packaging

Question 27

euchromatin

Answer 27

-Loosely packed chromatin

Question 28

heterochromatin

Answer 28

-highly condensed chromatin