Chapter 2

Question 1

bacteriophage

Answer 1

a virus that infects bacterial cells

Question 2

FISH

Answer 2

detect specific DNA sequences on a chromosome, uses fluorescent dye

Question 3

DNA

Answer 3

a nucleic acid composed of deoxyribonucleotides that carries the genetic information of a cell

Question 4

DNA molecule

Answer 4

generally refers to a double strand of DNA

Question 5

nucleotide

Answer 5

a molecule consisting of a five carbon sugar, phosphate, and nitrogen bases, DNA is a polymer of nucleotides containing deoxyribose

Question 6

phosphodiester bond

Answer 6

the covalent bond that connects two nucleotides in the backbone of DNA

Question 7

nucleic acid

Answer 7

a polymer composed of nucleotide monomers

Question 8

phosphodiester bond

Answer 8

chemical linkage between adjacent nucleotide residues in DNA

Question 9

complementary base pairing

Answer 9

association between specific nitrogenous bases of nucleic acids stabilized by hydrogen bonding, A with T and G with C

Question 10

antiparallel

Answer 10

the opposite orientation of the strands in a DNA double helix with one strand running 5 to 3 and 3 to 5

Question 11

double helix

Answer 11

secondary structure of DNA, consisting of two antiparallel DNA strands wound around each other

Question 12

chromatid

Answer 12

one half of two identical copies of a replicated chromosome

Question 13

sister chromatids

Answer 13

the identical chromatids of a recently replicated chromosome, connected at the centromere until separated at anaphase

Question 14

centromere

Answer 14

constricted region of a replicated chromosome where the two sister chromatids join until anaphase

Question 15

telomere

Answer 15

region of repetitive DNA sequences at the end of a chromosome, protect the ends, become slightly shorter after cell divides

Question 16

nucleosome

Answer 16

a section of DNA that is wrapped around a core of histone proteins

Question 17

histone

Answer 17

basic protein that act as spools around which DNA winds to create structural units called nucleosomes

Question 18

chromatin

Answer 18

a mixture of DNA and proteins that form the chromosomes found in Eukaryotic cells

Question 19

Euchromatin

Answer 19

more lightly packed chromatin that is more accessible for gene transcription

Question 20

Heterochromatin

Answer 20

tightly packed chromatin that is less accessible for transcription

Question 21

template strand

Answer 21

single strand of DNA used by DNA polymerase to synthesize a new strand

Question 22

semiconservative replication

Answer 22

the mechanism of replication used by cells to copy DNA, results: each daughter DNA molecule containing one old and one new

Question 23

semi-discontinuous replication

Answer 23

in replication one is replicated continuously and one is discon. in fragments

Question 24

bidirectional replication

Answer 24

refers to the replication of DNA in both directions from origins of replication

Question 25

origin of replication

Answer 25

site on the chromosome at which DNA replication begins

Question 26

replication bubble

Answer 26

where a double stranded molecule of DNA is separated into two single strands for bidirectional replication

Question 27

3' end

Answer 27

an end of DNA with a free OH group attached to the 3' carbon of the deoxyribose sugar

Question 28

5' end

Answer 28

an end of DNA with a free phosphate group attached to the 5' carbon of sugar

Question 29

leading strand

Answer 29

a single DNA strand that during DNA replication is replicated continuously in same direction as replication fork

Question 30

lagging strand

Answer 30

during DNA replication, its discontinuous and in the opposite direction of fork

Question 31

RNA primer

Answer 31

short segment of a single stranded RNA used as a binding site for DNA polymerase to initiate replication

Question 32

Okazaki fragment

Answer 32

short sections of DNA formed at the time of discontinuous synthesis of the lagging strand during replication

Question 33

primase

Answer 33

an enzyme that synthesizes RNA primers during DNA replication

Question 34

helicase

Answer 34

an enzyme that separates double stranded DNA into single strands allowing each strand to be copied

Question 35

topoisomerase

Answer 35

enzymes that catalyze changes in the topological state of DNA

Question 36

DNA ligase

Answer 36

a specific type of enzyme that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond between nucleotides

Question 37

single stranded DNA binding proteins

Answer 37

proteins that bind with high affinity to single stranded DNA to stabilize single strands during DNA replication

Question 38

sliding clamp

Answer 38

a ring shaped protein that encircles duplex DNA, binds to DNA polymerase and tethers it to the DNA template

Question 39

Telomerase

Answer 39

a reverse transcriptase that adds a species dependent telomere repeat sequence to the 3' end of telomeres