DNA replication

Question 1

DNA double helix stability is affected by what 5 things?

Answer 1

temp
- denature or melting

Cations
-stabilize the helix; reduce charge repulsion of the two strands

Base mismatchs
- destabilize the helix

Length of the helix
- longer helices are more stable

Proteins
-histones- positively charged proteins

Question 2

the complex of DNA double helix and proteins is called what?

Answer 2

histones which is a loosely packed form of DNA and DNA replication and gene expression

Question 3

what are the Two structures of bacterial DNA?

Answer 3

circular and supercoiled

Question 4

What is DNA replication?

Answer 4

the copying of DNA sequence

Question 5

When does DNA replication occur?

Answer 5

before the cell divides (S-Phase)

also some repair associated DNA replication can go on throughout the cell cycle

Question 6

Where does DNA replication happen?

Answer 6

Nucleus, mitochondria, chloroplast

Question 7

What is required for DNA replication?

Answer 7

must be coordinated with cell cycle

fidelity of replication must be very high

Question 8

How does DNA replication occur

?

Answer 8

replication is semi-conservative

each daughter helix has one old strand, one newly synthesized strand

Question 9

how are New nucleotides added?

Answer 9

added via the watson-crick pairing rule

Question 10

What materials are needed in DNA replication?

Answer 10

helicase: unwind

single strand binding protein- maintains ssDNA

topoisomerase: prevents overwinding ahead of replication fork

Primase: synthesize RNA primer

DNA polymerase 3: elongateds DNA by adding to primer

DNA polymerase 1 : removes RNA primers from 5’ end and replaces it with DNA

DNA ligase: joins strands of DNA