LECTURE 2 - STUDY GUIDE

Question 1

22. Regarding DNA replication, DNA replication begins at the ______ site and ends at a specific site called the _________. Fill in the blanks.

Answer 1

1. origin
2. terminus

Question 2

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

Answer 2

An enzyme that’s responsible for placing the polymerases

Question 3

24. 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

• DNA polymerase I: responsible for putting the very first amount of nucleotides where the origin site
  DNA polymerase II: only function it has is to repair
  DNA polymerase III: synthesizes all nucleotides in DNA, MAIN REPLICATION ENZYME

Question 4

25. Regarding DNA replication, what is a primer?

Answer 4

Primers

• A short stretch of DNA or RNA nucleotides hydrogen bonded to its completer strand
• Only needed within DNA Replication

Question 5

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

Answer 5

You will not be able to continue the DNA replication process

Question 6

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

Answer 6

Remove any nucleotides and must be cut out

Question 7

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

Answer 7

Endonuclease- inside DNA strand, cut out and repair
Exonuclease- outside on tips of DNA strand, cut out and repair

Question 8

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

Answer 8

Difference: lagging strand is discontinuous and leading strand is continuous
Similarity:

Question 9

30. 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

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

Answer 10

Helicase: area that will unwind your double helix (unzips) so the replication fork opens

Primase: makes primer

DNA gyrase: relieves torque, zips up DNA segments and use for DNA repair

DNA ligase: 2 functions, joins the end of DNA segments and use for DNA repair

Question 11

32. 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 are usually not stable in aqueous environments

Question 12

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

Answer 12

Initiating process, getting stuff ready

Question 13

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

Answer 13

Actively opening up replication fork

Question 14

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

Answer 14

Finishes the process of replication

Question 15

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

Answer 15

Time of replication :

Eukaryotic - S phase

Prokaryotic - end of cell cycle

Question 16

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

Answer 16

Direction of replication: both 3-5 and 5-3

Replication Model: both semi-conservative