CH 12 DNA Replication and Manipulation Reading Guide Flashcards Preview

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Flashcards in CH 12 DNA Replication and Manipulation Reading Guide Deck (20):
1

Explain semi conservative and conservative DNA?

Semi conservative: one strand of the newly formed DNA will be from the parent and another strand will be brand newConservative both strands are from the parents no new strand is created

2

What method did me seldom and stahl up to identify parental and newly synthesized DNA strands?

They labeled the different strands with different isotopes of nitrogen

3

Explain the three main steps of the modelson and stahl experiment?

1 both strands of DNA are labeled with heavy nitrogen which forms a band of heavy DNA2 after one round of replication one strand contains heavy nitrogen and one strand contains light nitrogen therefore net lighter3. After two rounds of replication two strand of light nitrogen and one stand of heavy and one strand of light similar to step 2

4

How are the two daughter strands different after replication?

There anti parallel to one another

5

What is the enzyme called that is required to catalyze the addition of new nucleotides? Do they synthesize DNA from an existing template.

DNA polymeraseYes

6

Define leading strand

The daughter strand that has its 3' end pointing towards the replication fork

7

Define lagging strand

The daughter strand that has its 3' end pointing away from the replication fork

8

Define Okazaki fragments

Short pieces found within the lagging strand

9

Define a primer

Short stretch of RNA that serves as the starting point for a strand of DNA

10

What type of enzyme is primase?

A type of RNA polymerase

11

Why does DNA polymerase require a primer in order to do its job?

So that it knows where to start copying

12

What happens to DNA primers during the process of DNA replication?

Gets replaced by DNA nucleotides

13

What do DNA ligases do?

Joins the fragments of DNA together

14

Define proofreading

A process when DNA polymerase correct there own copying errors

15

How good is DNA polymerase at finding errors

99%

16

Define a mutation in the context of DNA polymerase?

When mistakes slip past the proofreading process Some mistakes in coding may cause harmful changes to the genetic code

17

What is the function of helicase?

To unwind the parental double helix at the replication fork

18

What do topoisomerases do?

Removes stress associated wight the unwinding at the replication fork

19

What do single stranded binding proteins do?

Bind the resulting single stranded regions of DNA to prevent the template strands from coming back together

20

How are the deoxyribose sugars linked together in a DNA strand?

Phosphate group