Chapter 16: DNA Replication

Question 1

Fredrick Griffith

Answer 1

He took Living S cell : Mouse dead
Living R Cell: Mouse alive
Dead S Cell: Mouse Alive
Dead s Cell & Living R Cell: Mouse Dies
The S Cell’s DNA jumped to R Living making it deadly

He called this the transformative factor

Question 2

Hershey & Chase Experiment

Answer 2

They found an isotope (S)for the protein & one for the DNA(P) to make them glow to track them from the virus to the bacteria.

When they mixed the virus and bacteria together. The bacteria glowed the color of the of the DNA.

Meaning the the DNA was the trans-formative factors

Question 3

Structure of DNA

Answer 3

Double helix, sugar phosphate backbone, nitrogen bases interior

Question 4

How far apart is the bases are from each other?

Answer 4

They are equally spaced from each other

Question 5

Why is DNA two strands?

Answer 5

It’s for replication and used as a to correct errors and removal of damage to DNA

Question 6

Chargaff’s Rules

Answer 6

DNA composition
- varies b/tw species
- all 4 bases not in equal quantity
- bases present in characteristic ratio

Humans

A: 30.9%
T: 29.4%
G: 19.9%
C: 19.8%

Question 7

DNA Polymerase I

Answer 7

It removes the RNA primer, and replaces it with DNA nucleotide. It checks your cells don’t have any mutations.

Can only build onto 3’ end of an existing DNA strand.

Question 8

Who figured out the structure of DNA?

Answer 8

Watson, Crick, and Franklin

Question 9

How are bases arranged ?

Answer 9

Purine + Prymidine

Question 10

What is the 3 parts of DNA nucleotide

Answer 10

Phosphate group PO4

Deoxyribose 5 carbon sugar

N Base

• Adenine Thymine
• Guanine Cytosine

Question 11

Anti- Parallel Strands

Answer 11

The backbone of DNA starts opposite of each other. So, one strand starts from 3-5 while the other starts 5-3. Due to the face that DNA has direction & complementary strands run opposite direction

Question 12

How to know if it’s 3-5 or 5-3 strand

Answer 12

If the Phosphorus is on top it is a 5-3 strand or is the first thing you see, and at the bottom there is an OH. If the phosphorus is at the bottom and OH is at the top then it’s 3-5

Question 13

Purines

Answer 13

A & G

Question 14

Pyrimidines

Answer 14

T & C

Question 15

What pairs w/ A

Answer 15

T & 2 H-bonds

Question 16

What pairs w/ G

Answer 16

C & has 3 H-bonds

Question 17

1st step of Replication

Answer 17

Unwind DNA

The helicase enzymes unwinds DNA from the middle to both ends of the DNA

DNA strands are stabilized by the single strand binding proteins after unwinding

Question 18

Helicase

Answer 18

Enzyme that unwinds DNA

Question 19

Single- Stranded Binding Proteins

Answer 19

Stabilizes the DNA strands after it gets unwind by helicase

Question 20

2nd Step of Replication

Answer 20

Build daughter DNA strand
- add new complementary bases

This is done by DNA Polymerase III can only add nucleotides to 3’ -5’ (leading strand)end of a growing DNA strand since the strand can only grows 5’—3’
— Need a starter nucleotide to bond to

Question 21

Where does the energy for bonding the phosphorus group to the sugar

Answer 21

The nucleotides arrived as nucleosides
- DNA w/ P-P-P (ATP, GTP, TTP, CTP)

The DNA bases arrive w/ their own energy for the binding process this is used by DNA polymerase III (enzyme) to bond

Question 22

How does the body help make up for the limits of DNA

Answer 22

On the lagging strand ( 5’-3’ ) uses Okazaki fragments in order to keep up w/ the leading strand the gaps between the fragments are joined together by ligase

Question 23

Limits of DNA polymerase III

Answer 23

Can only build onto 3’ end of an existing DNA strand

Question 24

RHA primer

Answer 24

built by primase serves as a starter sequence for DNA polymerase III

Question 25

Why must RNA primase must exist?

Answer 25

DNA Polymerase III is only able to add nucleotides to an existing nucleotide chain; it can’t “start from scratch” and therefore needs RNA primer to start process

Question 26

What do all DNA have in common?

Answer 26

Can only add to the 3’ end of an existing DNA strand

Question 27

Why do chromosomes get shorter at each replication?

Answer 27

loss of bases at the 5’ ends in each replication

Question 28

Telomeres

Answer 28

repeating, non-coding sequences at the end of chromosomes=protective cap

Question 29

Telemerase

Answer 29

enzyme extends tel