DNA Replication

Question 1

What is a chromosome?

Answer 1

-the tightly wound DNA inside a chromatid

Question 2

What are histones?

Answer 2

-proteins which DNA wraps around

Question 3

What are genes?

Answer 3

-certain sections of DNA which contain certain code

Question 4

What is chromatin?

Answer 4

-Loosely wound DNA

Question 5

What nucleotides pair with each other?

Answer 5

• A and T
• C and G
• A and U

Question 6

What happens in step 1 of DNA replication?

Answer 6

• called unzipping

- helicase pulls apart hydrogen bonds creating replication fork or loose strands called lagging and leading strand

Question 7

What occurs in step 2 of DNA replication?

Answer 7

• called priming

- a strand of RNA with a complementary sequence of nucleotides is found

Question 8

What is the leading strand?

Answer 8

-The loose strand which has 3 at the end which is connecting to the primer, allowing the primer to run down the DNA without stopping.

Question 9

What is the lagging strand?

Answer 9

-The strand which has 5 at the end, which causes the strand to need multiple primers, as the primer reaches the edge of the strand and other primers

Question 10

Which way does the primer run?

Answer 10

-5-3, so if the DNA strand runs 5-3 the 5 of the primer will start at the 3 of the DNA, and the opposite for the other strand

Question 11

What occurs in step 3 of DNA replication?

Answer 11

• primer is attached to DNA stand via an enzyme called DNA polymerase
• DNA polymerase reads DNA strand and adds new nucleotides to create a new strand

Question 12

What are Okazaki fragments?

Answer 12

-The section between primers on the lagging strand

Question 13

What occurs in step 4 of DNA replication?

Answer 13

• primers removed by exonuclease
• gaps are filled in with nucleotides
• strands are proof read
• DNA ligase glues DNA back together (restoring hydrogen bonds)