Ch 10 Book Terms

Question 1

Replicon

Answer 1

A unit of the genome in which DNA is replicated. Each contains an origin for initiation of replication.

Question 2

Origin

Answer 2

A sequence of DNA at which replication is initiated.

Question 3

Terminus

Answer 3

A segment of DNA at which replication ends.

Question 4

Plasmid

Answer 4

Circular, extrachromosomal DNA. It is autonomous and can replicate itself.

Question 5

Single Copy

Answer 5

A type of replication control in bacteria resulting from the fact that a genome in a bacterial cell has a single replication origin and thus constitutes a single replicon. Because units of replication and segregation coincide, initiation at a single origin
sponsors replication of the entire genome, once for every cell division.

Question 6

Semiconservative Replication

Answer 6

DNA replication accomplished by separation of the strands of a parental duplex, each strand then acting as a template for synthesis of a complementary strand.

Question 7

Replication Bubble

Answer 7

A region in which DNA has been replicated within a longer, unreplicated region.

Question 8

Replication Fork (Growing Point)

Answer 8

The point at which strands of parental duplex DNA are separated so that replication can proceed. A complex of proteins including DNA polymerase is found there.

Question 9

Unidirectional Replication

Answer 9

The movement of a single replication fork from a given origin.

Question 10

Bidirectional Replication

Answer 10

A system in which an origin generates two replication forks that proceed away from the origin in opposite directions.

Question 11

Hemimethylated DNA

Answer 11

DNA that is methylated on one strand of a target sequence that has a cytosine on each strand.

Question 12

Licensing Factor

Answer 12

A factor located in the nucleus and necessary for replication; it is inactivated or destroyed after one round of replication. New factors must be provided for further rounds of replication to occur.

Question 13

Helicase

Answer 13

An enzyme that uses energy provided by ATP hydrolysis to separate the strands of a nucleic acid duplex.

Question 14

Single-Strand Binding Protein (SSB)

Answer 14

The protein that attaches to single-stranded DNA, thereby preventing the DNA from forming a duplex.

Question 15

Primase

Answer 15

A type of RNA polymerase that synthesizes short segments of RNA that will be used as primers for DNA replication.

Question 16

S Phase

Answer 16

The restricted part of the eukaryotic cell cycle during which synthesis of DNA occurs.

Question 17

Checkpoint

Answer 17

A biochemical control mechanism that prevents the cell from progressing from one stage to the next unless specific goals and requirements have been met.

Question 18

Autonomously Replicating Sequence (ARS)

Answer 18

A DNA sequence element that contains an origin of replication.

Question 19

A Domain

Answer 19

The conserved 11-bp sequence of A-T base pairs in the yeast ARS element that comprises the replication origin.

Question 20

Origin Recognition Complex (ORC)

Answer 20

Found in eukaryotes, a multiprotein complex that binds to the replication origin, the autonomously replicating sequence (ARS), and remains associated with it throughout the cell cycle.

Question 21

Prereplication Complex

Answer 21

A protein–DNA complex at the origin in Saccharomyces cerevisiae that is required for DNA replication. The complex contains the ORC complex, Cdc6, and the MCM proteins.

Question 22

Postreplication Complex

Answer 22

A protein–DNA complex in Saccharomyces cerevisiae that consists of the ORC complex bound to the origin.