3.4 DNA Replication

Question 0

Explain DNA replication in terms of unwinding the double helix and separation of the strands by helicase, followed by the formation of the new complementary strands by DNA polymerase

Answer 0

Helicase

• unwinds the DNA
• separates the double helix by breaking the hydrogen bonds between complementary base pairs
• 2 separate stands = template for synthesis of new DNA

DNA Polymerase

• synthesizes new stands from 2 parental template strands
• free deoxynueoside triposhates aligned through complementary base pairing
• Covalently bonded through DNA polymerase III

Question 1

What key word describes DNA replication?

Answer 1

Semiconservative: half of a pre-existing DNA molecule is always conserved [saved].

Question 2

Explain the significance of complementary base pairing in the conversation of the base pairing In the conversation of the base sequence of DNA

Answer 2

• each nitrogenous base can only pair w/ complementary partner (a-T, G-C)
• when DNA replicated new strands formed are identical to original strands separated from template b/c nitrogenous bases pair in the same matter as original DNA
• 2 DNA molecules identical to original molecule