DNA replication

Question 0

What are types of DNA damages that can occur when exposed to UV light?

Answer 0

1) . thymidine dimers - fixed by nucleotide excision repair

2. ) UV deamination - fixed by base excision repair

Question 1

What bonds connect DNA molecules

Answer 1

dinucleotide triphosphates are joined via 3 to 5’ phosphodiester bonds

Question 2

What are other types of DNA damage that can occur?

Answer 2

1. Dealkylation/depurination

2. Intercalation

Question 3

Why do we need a primer?

Answer 3

nucleotides are added by the 3’OH on one nucleotide attacking the 5’ phosphate group on another, therefore the first DNA base needs something to attack it, so you add the RNA primer

Question 4

Why do eukaryotes need multiple origins of rep?

Answer 4

a lot more DNA

Question 5

How does exonuclease activity identify the right strand in mistmatch repair?

Answer 5

The daughter strand has nicks that have not been worked out by DNA ligase yet

Question 6

Holiday structure

Answer 6

X type structure from general recombination after both strands and nicked and exchanged; RecA bacterial protein important in identifying homologous structures for recomb.

Question 7

Site specific recombination

Answer 7

Driven by recombination enzymes that recongize specific sequennces on DNA strands; found in viruses that incorporate into host genome like HIV and bacteriophage lambda ; recombination is how antibodies are created in immune cells
- Transposable elements encode recombinases