DNA Replication and Recombination Quiz

Help study for Lecture Exam 3

The amount of DNA that is replicated from a single origin of replication is referred to as a(n) ________.

replicon

DNA replication occurs by adding ________.

dNTPs to the 3' end of the daughter strand

Which terms accurately reflect the nature of replication of the chromosome in E. coli?

bidirectional and fixed point of initiation

DNA Pol III is believed to be responsible for removing the primer.

False

DNA Pol I, II, and III all possess 3' to 5' exonuclease activity.

True

DNA polymerases can all perform 5' to 3' polymerization.

True

DNA Pol I, II, and III all possess 5' to 3' exonuclease activity.

False

DNA polymerases are important in various aspects of DNA repair.

True

DNA polymerases can all initiate DNA synthesis on a template on their own.

False

Which activity of E. coli DNA polymerase I is responsible for proofreading the newly synthesized DNA?

3' to 5'; exonuclease

The protein responsible for the initial step in unwinding the DNA helix during replication of the bacterial chromosome is coded for by the ________ gene.

dnaA

During DNA replication, ________ are 1000-2000 nucleotide long strands synthesized on the ________ strand to maintain the ________ of replication.

Okazaki fragments; lagging; bidirectionality

Which enzyme is responsible for relieving the tension ahead of the fork that results when the DNA unwinds to form the replication "bubble" or "eye"?

DNA gyrase

Which of the following statements about DNA replication is true?

DNA synthesis is continuous on the leading strand and discontinuous on the lagging strand.

As unwinding of the helix occurs during DNA replication, tension referred to as ________ is created ahead of the replication fork. This tension is relieved by the action of ________.

supercoiling; DNA gyrase

DNA replication in eukaryotes ________.

initiates at multiple origins

Chromatin is defined as ________.

DNA complexed with protein

Continuous on one strand and discontinuous on the other strand.

Prokaryotic and Eukaryotic

The only replication origin in a chromosome

Prokaryotic Replication

Euchromatin and heterochromatin replicate at different times

Eukaryotic Replication

Long Okazaki fragments (about 1000 nucleotides)

Eukaryotic Replication

Multiple replication origins

Eukaryotic Replication

Bidirectional

Prokaryotic replication

Short Okazaki fragments (about 100 nucleotides)

Prokaryotic replication

The process of making DNA from an RNA template is referred to as ________.

reverse transcription

Which term describes a genetic exchange between two DNA molecules with substantial DNA sequence homology?

homologous recombination

The new DNA in the daughter strand is interspersed among the old pieces

dispersive

The old DNA is completely conserved

conservative

Each daughter strand is composed of one old DNA strand and one new DNA strand

semiconservative

Separation of the individual covalent, phosphodiester bonds is required for this mode of replication

dispersive

The original DNA strand is broken into pieces

dispersive

The original double helix remains as a complete unit

conservative

The new DNA double helix is produced as a single unit

Conservative

Kornberg showed that nucleotides are added to the 3'-end of each growing DNA strand.

In what way does an exposed 3'-OH group participate in strand elongation?

It directly participates in the formation of a covalent bond with the nucleotide being added

Can you distinguish between (a) unidirectional and bidirectional synthesis, and (b) continuous and discontinuous synthesis of DNA?

This diagram depicts an origin of replication, with the direction of the movement of the replication fork indicated.

unidirectional

Given the direction of replication and the orientation of the two DNA strands, which of the following is true?

Select the two true statements.

-The bottom strand (blue) is the lagging strand; it is being synthesized discontinuously

-The top strand (pink) is the leading strand; it is being synthesized continuously

Primase

Not involved in the unwinding of DNA for replication

DNA gyrase (topoisomerase)

Release supercoiling by nicking DNA

DNA polymerase

Not involved in the unwinding of DNA for replication

Helicase

Opens DNA Double Helix

DnaA replication initiation factor protein

Not involved in the unwinding of DNA for replication

Single-stranded binding protein

Stabilizes the open conformation

DNA ligase

Not involved in the unwinding of DNA for replication

Consider the drawing of a dinucleotide below. Is it DNA or RNA ?

DNA

Consider the drawing of a dinucleotide below. Is the arrow closest to the 5' or the 3' end?

3’