Test 7 - Lecture 2

Question 1

Regarding DNA replication, DNA replication begins at the ______________ site and ends at a specific site called the _______________. Fill in the blanks.

Answer 1

Origin of replication, Terminus

Question 2

Regarding DNA replication, What is the main function of something within the polymerase class of enzymes?

Answer 2

Responsible for placing nucleotides and synthesize nucleic acid

Question 3

Regarding DNA replication, which statement accurately describes the function of (a) DNA polymerase I, (b) DNA polymerase II, or (c) DNA polymerase III?

Answer 3

A) Adds new nucleotides to the 3’ ends
B) Repairs processes
C) Synthesizes all nucleotides

Question 4

Regarding DNA replication, what is a primer?

Answer 4

Works with DNA polymerase

Question 5

Regarding DNA replication, what happens if no primer is present?

Answer 5

You will not have any DNA replicated as they are only needed in replicating DNA

Question 6

Regarding DNA replication, what is the main function of an nuclease?

Answer 6

Remove any enzyme that does not belong there

Question 7

Regarding DNA replication, what is the difference between an endonuclease and an exonuclease?

Answer 7

Endonuclease: INSIDE, cut out and repair
Exonuclease: Tips of DNA strand OUTSIDE, remove

Question 8

Regarding DNA replication, which statement accurately describes a (a) difference or (b) similarity between the leading and lagging strands of DNA templates?

Answer 8

A) Lagging strands are DISCONTINUOUS and are synthesized by the addition of nucleotides to THE 5’ END, while leading strands are CONTINUOUS and are synthesized by the addition of nucleotides to THE 3’ END
B) Both are synthesized by the addition of nucleotides

Question 9

The site of the opening of the DNA strand where active replication occurs (and other enzymatic activities) is called the ______________. Fill in the blank.

Answer 9

Replication fork

Question 10

Regarding DNA replication, which statement accurately describes the function of (a) helicase, (b) primase, (c) DNA gyrase, or (d) DNA ligase?

Answer 10

A) Area that unwinds/unzips the double helix to allow the replication fork to be open
B) Makes primers
C) Relieves torque and zips up the DNA behind the replication, prevents spinning or breakage
D) Joins the end of the DNA segments and does DNA repair

Question 11

Regarding DNA replication, what is the definition or function (i.e. why is it needed) of a single-stranded binding protein?

Answer 11

Stabilizes single-stranded regions which aren’t usually stable in aqueous environments

Question 12

There are three main stages of DNA replication. Which statement describes the initiation stage (only as discussed in class)?

Answer 12

The first stage of DNA replication, does not have an open replication fork, if going into next stage you must create proteins and enzymes, making everything and looking for primers

Question 13

There are three main stages of DNA replication. Which statement describes the elongation stage (only as discussed in class)?

Answer 13

DNA Polymerase III will add new nucleotides to template strand

Question 14

There are three main stages of DNA replication. Which statement describes the termination stage (only as discussed in class)?

Answer 14

DNA gyrase reaches the site and finishes the process

Question 15

What is a difference between eukaryotic and prokaryotic DNA replication (know the chart on PPT Chapter 14 Slide 21)?

Answer 15

Eukaryotes: Occurs in S phase in the nucleus, uses DNA polymerase alpha, delta, gamma, and epsilion, has a more complex mechanism, has many active replication sites, 50 bases replication/sec, and 1500 bases for length of okazaki fragments

Prokaryotes: Occurs at the end of the cell cycle within the cytoplasm, uses enzymes DNA polymerase I, II, and III, simple mechanism, one active replication site, 500 bases replication/sec, and 150 bases for length of okazaki fragments

Question 16

What is a similarity between eukaryotic and prokaryotic DNA replication (know the chart on PPT Chapter 14 Slide 21)?

Answer 16

Both use pre-existing DNA as the template, use 3-5 and 503 directions of replication, and have semi-conservative replication models