DNA Replication

What are the three parts of a nucleotide in DNA?

Deoxyribose, phosphate group, and nitrogenous base.

What is the orientation of the DNA strands?

anti-parallel, with one strand running 5’ to 3’ and the other 3’ to 5’.

Which base pairs form three hydrogen bonds?

Cytosine and Guanine (C-G)

What is the nature of DNA replication?

semi-conservative, meaning each new DNA molecule consists of one original strand and one newly synthesized strand.

What enzyme unwinds the DNA double helix during replication?

Helicase

What is the role of primase in DNA replication?

synthesizes RNA primers using the parental strand as a template.

What differentiates the leading strand from the lagging strand?

The leading strand is synthesized continuously, whereas the lagging strand is synthesized discontinuously in Okazaki fragments.

What enzyme replaces RNA primers with DNA nucleotides?

DNA polymerase I

What are telomeres?

repetitive segments at the end of DNA strands that protect coding sequences from being shortened during replication.

What mechanism allows DNA Polymerase to correct errors during replication?

proofreading ability to remove and replace incorrect base pairs during replication.

When does a mismatch repair occur and what is its purpose?

occurs right after replication to correct incorrect nucleotides and remove slight insertions/deletions.

What occurs during base excision repair?

A glycosylase removes the incorrect base, and then DNA Polymerase fills the gap with the correct nucleotide.

What type of repair deals with covalent bonding of adjacent thymine dimers?

nucleotide excision repair.

What is a consequence of double strand breaks in DNA?

loss of important genes.