ch 11 dna replication

Question 1

dna replication

Answer 1

the process in which original dna strands are used as templates for the synthesis of new dna strands

Question 2

template strand

Answer 2

(also called parental strand) a strand of dna that is used to synthesize a complementary strand of dna or rna

Question 3

daughter strands

Answer 3

in dna replication, the two newly made strands of dna

Question 4

conservative model

Answer 4

an incorrect model of dna in which both parental strands of dna remain together following dna replication

Question 5

semiconservative model

Answer 5

the correct model for dna replication which the newly made double-stranded dna contains one parental strand and one daughter strand

Question 6

dispersive model

Answer 6

an incorrect model for dna replication in which segments of parental dna and newly made dna are interspersed in both strands following the replication process

Question 7

origin of replication

Answer 7

a site on a chromosome that functions as an initiation site for the assembly of several proteins that begin the process of dna replication

Question 8

bidirectional

Answer 8

1. the manner in which two replication forks move, in opposite directions outward from the origin
2. refers to a regulatory element that can function in either the forward or reverse direction

Question 9

replication fork

Answer 9

the region in which two dna strands have separated and new strands are being synthesized

Question 10

dnaA protein

Answer 10

a protein that binds to a dnaA box sequence at the origin of replication in bacteria and initiates replication

Question 11

dnaA box

Answer 11

a dna sequence that serves as a recognition site for the binding of a dnaA protein

Question 12

dna helicase

Answer 12

an enzyme that separates the two strands of dna

Question 13

bidirectional replication

Answer 13

the phenomenon in which two dna replication forks emanate in opposite directions from an origin of replication

Question 14

topoisomerase ii

Answer 14

(also called dna gyrase) an enzyme that introduces negative supercoils into dna using energy from atp and that can also relax positive supercoils when they occur

Question 15

single-stranded binding protein

Answer 15

proteins that bind to both of the single strands of dna during dna replication and percent them from reforming a double helix

Question 16

rna primer

Answer 16

a short strand of rna, made by primase, that is used to elongate a strand of dna during dna application

Question 17

primase

Answer 17

an enzyme that synthesizes short rna primers during dna replication

Question 18

leading strand

Answer 18

a strand during dna replication that is synthesized continuously toward the replication fork

Question 19

lagging strand

Answer 19

a strand during dna replication that is synthesized as short okazaki fragments in the direction away from the replication fork

Question 20

dna polymerase

Answer 20

an enzyme that catalyzes the covalent attachment of nucleotides to form a strand of dna

Question 21

okazaki fragments

Answer 21

short segments of dna that are synthesized to produce the lagging strand during dna replication

Question 22

dna ligase

Answer 22

an enzyme that catalyzes the formation of a covalent bond within the sugar-phosphate backbones of two dna strands

Question 23

primosome

Answer 23

a protein complex that includes dna helicase and primase

Question 24

replisome

Answer 24

a complex that contains a primosome and dimeric dna polymerase

Question 25

dimeric dna polymerase

Answer 25

a complex of two dna polymerase holoenzymes that move as a unit during dna replication

Question 26

termination (ter) sequences

Answer 26

in e. coli, a pair of sequences in the chromosome that bind a protein known as the termination utilization substance (Tus), which stops the movement of replication forks

Question 27

catenanes

Answer 27

intertwined circular molecules

Question 28

conditional mutant

Answer 28

a mutant whose phenotype depends on the environmental conditions, such as a temperature-sensitive mutant

Question 29

temperature-sensitive (ts) mutant

Answer 29

a mutant that has a normal phenotype at a permissive temperature but a different phenotype, such as failure to grow, at a nonpermissive temperature

Question 30

processive enzyme

Answer 30

an enzyme, such as rna or dna polymerase, which glides along the template strand and does not dissociate from it while catalyzing the covalent attachment of nucleotides

Question 31

fidelity

Answer 31

a term used to describe the accuracy of a process; if there are few mistakes, a process has a high fidelity

Question 32

proofreading function

Answer 32

the ability of dna polymerase to remove mismatched bases from a newly made strand

Question 33

ars elements

Answer 33

dna sequences found in yeast that function as origins of replication

Question 34

prereplication complex (preRC)

Answer 34

in eukaryotes, an assembly of at least 14 different proteins, including a group of proteins called the origin recognition complex (ORC), which acts as the first initiator of preRC assembly

Question 35

origin recognition complex (ORC)

Answer 35

a group of proteins found in eukaryotes that acts as the first initiator of preRC assembly to begin dna replication

Question 36

mcm helicase

Answer 36

a group of six proteins needed to complete a process called dna replication licensing, which is necessary for the formation of two replication forks at an origin of replication in eukaryotes

Question 37

dna replication licensing

Answer 37

in eukaryotes, occurs when mcm helicase is bound at an origin of replication enabling the formation of two replication forks

Question 38

polymerase switch

Answer 38

an exchange of one type of dna polymerase for another type during dna replication

Question 39

translesion-replicating polymerase

Answer 39

a type of dna polymerase that can replicate over a dna region that contains an abnormal structure (ie a lesion)

Question 40

flap endonuclease

Answer 40

an enzyme that removes small rna flaps that are generated by the action of dna polymerase δ; removes rna primers during dna replication

Question 41

telomeres

Answer 41

specialized repeated sequences found at the ends of eukaryotic chromosomes

Question 42

telomerase

Answer 42

the enzyme that recognizes telomeric sequences at the ends of eukaryotic chromosomes and synthesizes additional repeats of those telomeric sequences

Question 43

telomerase rna component (TERC)

Answer 43

the rna component of telomerase

Question 44

telomerase reverse transcriptase (TERT)

Answer 44

the enzyme within telomerase that uses rna as a template to make dna

Question 45

senescent

Answer 45

describes a cell that is no longer capable of dividing