DNA Replication Overview Quiz

DNA Replication Overview

• DNA replication is semi-conservative, with each new double-helix containing one original parent strand.
• It is characterized as an anabolic process since it builds new DNA strands.

Nucleotide Structure

• A nucleotide consists of three components: nitrogenous base, phosphate group, and deoxyribose sugar.

Nitrogenous Bases

• Pyrimidine bases include thymine (T) and cytosine (C).
• Purine bases consist of adenine (A) and guanine (G).

DNA Replication Mechanics

• The starting point for replication is called the Point of Origin.
• Helicase is responsible for unzipping the DNA helix by breaking the hydrogen bonds between nitrogen bases.

Strand Synthesis

• The lagging strand is synthesized towards the replication fork, requiring more RNA primers due to its synthesis occurring in the opposite direction.
• The leading strand is synthesized continuously.

Key Enzymes and Their Functions

• Helicase: Unzips the double helix.
• Primase: Lays down RNA primers for DNA polymerase to follow.
• Polymerase: Adds free-floating nucleotides to synthesize the new DNA strand.
• Ligase: Glues nucleotides together on the lagging strand.

Base Pairing Strength

• Guanine (G) and cytosine (C) pairs are harder to split than adenine (A) and thymine (T) pairs due to G and C forming three hydrogen bonds, compared to the two hydrogen bonds in A and T.

5' and 3' Ends

• DNA strands have a 5' end with a phosphate group and a 3' end with a hydroxyl group.