Chapter 11 Dna Replication

Front 1

Bidirectionality

Back 1

the phenomenon in which two replication forks move in opposite directions, outward from the origin.

Front 2

Bidirectional replication

Back 2

the phenomenon in which two DNA replication forks emanate in both directions from an origin of replication.

Front 3

Catenanes

Back 3

interlocked circular molecules.

Front 4

Conservative model

Back 4

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

Front 5

Daughter strands

Back 5

in DNA replication, the newlymade strand of DNA.

Front 6

Dimeric DNA polymerase

Back 6

a complex of two DNA polymerase proteins that move as a unit during DNA replication

Front 7

Dispersive model

Back 7

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.

Front 8

Dam

Back 8

an enzyme in bacteria that attaches methyl groups to the adenine base in DNA that is found within the sequence GATC.

Front 9

DNA gyrase

Back 9

also known as topoisomerase II; an enzyme that introduces negative supercoils into DNA using energy from ATP. Gyrase can also relax positive supercoils when they occur.

Front 10

DNA helicase

Back 10

an enzyme that separates the two strands of DNA.

Front 11

DNA ligase

Back 11

an enzyme that catalyzes a covalent bond between two DNA fragments

Front 12

DNA polymerase

Back 12

an enzyme that catalyzes the covalent attachment of nucleotides together to form a strand of DNA.

Front 13

DNA replication

Back 13

the process in which originalDNA strands are used as templates for thesynthesis of new DNA strands.

Front 14

DnaA box sequences

Back 14

serves as a recognition sitefor the binding of the DnaA protein, which is involved in the initiation of bacterial DNA replication.

Front 15

DnaA proteins

Back 15

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

Front 16

Fidelity

Back 16

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

Front 17

Flap endonuclease

Back 17

an enzyme that removes smallpieces of RNA flaps that are generated by the action of DNA polymerase δ. It removes RNA primers during DNA replication.

Front 18

Lagging strand

Back 18

a strand during DNA replication that is synthesized as short Okazaki fragments in the direction away from the replication fork.

Front 19

Leading strand

Back 19

a strand during DNA replication that is synthesized continuously toward the replication fork.

Front 20

Okazaki fragments

Back 20

short segments of DNA that are synthesized in the lagging strand during DNA replication.

Front 21

Origin ofreplication

Back 21

a nucleotide sequence that functions as an initiation site for the assembly of several proteins required for DNA replication.

Front 22

Originrecognition complex (ORC)

Back 22

a complex of six proteins found in eukaryotes that is necessary to initiate DNA replication.

Front 23

Parentalstrands

Back 23

in DNA replication, the DNA strand that is used as a template.

Front 24

PolymeraseSwitch

Back 24

during DNA replication, when one type of DNA polymerase (e.g., α) is switched for another type (e.g., β).

Front 25

Prereplicationcomplex (preRC)

Back 25

in eukaryotes, an assembly of at least 14 different proteins, including a group of 6 proteins called the origin recognition complex (ORC), that acts as the initiator of eukaryotic DNA replication

Front 26

Primase

Back 26

an enzyme that synthesizes a short RNA primer during DNA replication.

Front 27

Primosome

Back 27

a multiprotein complex composed of DNA helicase, primase, and several accessory proteins.

Front 28

Processive enzyme

Back 28

an enzyme, such as RNA and DNA polymerase, which glides along the DNA and does not dissociate from the template strand as it catalyzes the covalent attachment of nucleotides.

Front 29

Proofreadingfunction

Back 29

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

Front 30

Replicationforks

Back 30

the region in which two DNAstrands have separated and new strands arebeing synthesized.

Front 31

Replisome

Back 31

a complex that contains a primosomeand dimeric DNA polymerase.

Front 32

RNA primers

Back 32

a short strand of RNA, made by DNA primase, that is used to elongate a strand of DNA during DNA replication

Front 33

Semiconservativemodel

Back 33

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

Front 34

Single-strandbinding proteins

Back 34

a protein that binds to both of the single strands of DNA during DNA replication and prevents them from re-forming a double helix.

Front 35

Telomerase

Back 35

the enzyme that recognizestelomeric sequences at the ends of eukaryotic chromosomes and synthesizes additional numbers of telomeric repeat sequences.

Front 36

Telomeres

Back 36

specialized DNA sequences found at the ends of linear eukaryotic chromosomes.

Front 37

Templatestrands

Back 37

a strand of DNA that is used to synthesize a complementary strand of DNA or RNA.

Front 38

Terminationsequences

Back 38

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 the replication forks.

Front 39

Topoisomerase(type II)

Back 39

during DNA replication, thisprotein travels in front of DNA helicase andalleviates positive supercoiling.

Front 40

Tus

Back 40

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 the replication forks.