Lecture 7: DNA Replication and PCR

What are the four different nucleotides in DNA?

Adenine (A), Thymine (T), Cytosine (C), Guanine (G)

What is the structure of DNA?

Double-stranded helix

What is the size of the human genome?

3.2 billion base pairs (bp)

What does 'semi-conservative' mean in DNA replication?

Each new DNA double helix contains one old strand and one new strand.

What is the role of Ori C in DNA replication?

It is the origin of replication where DNA strands separate easily due to A/T consensus sequences.

What is the function of DNA Polymerase III?

It adds nucleotides to the growing DNA strand in a 5' to 3' direction.

How fast does DNA Polymerase III add bases?

33 bases per second

What are Okazaki fragments?

Short DNA fragments synthesized on the lagging strand during DNA replication.

What is the role of Primase in DNA replication?

It creates a small RNA primer to initiate DNA synthesis.

What is the function of DNA Ligase?

It joins Okazaki fragments by linking the 3' end of one fragment to the 5' end of another.

What is required to replicate DNA in a test tube?

Template DNA, dNTPs, DNA Polymerase, and a short DNA primer.

What is the significance of Taq DNA Polymerase in PCR?

It is derived from heat-loving bacteria and can withstand high temperatures needed for DNA replication.

What temperature range is optimal for Taq DNA Polymerase?

70-75 °C

What are the main components needed for PCR?

DNA template, dNTPs, Taq DNA Polymerase, primers, and heating/cooling equipment.

What is the purpose of performing PCR?

To amplify trace amounts of DNA for easier detection and analysis.

What are the outcomes of PCR?

Easier detection and analysis, isolation and purification of samples, preservation and sharing of material.

What is the challenge of DNA polymerization?

The need for specific base-pair sequences and the integrity of the DNA structure.

What happens to DNA at high temperatures during PCR?

The double strands separate, allowing for single-stranded templates.

What is the dilemma faced when using human DNA Polymerase in PCR?

It denatures at high temperatures needed to keep DNA unwound.

What is a replicon?

A site of new strand synthesis during DNA replication.

What is the role of Helicase in DNA replication?

It opens the replication fork by unwinding the DNA strands.

What is the significance of the consensus sequence in DNA replication?

It allows for easier separation of DNA strands at the origin of replication.

How does temperature affect DNA structure?

Heating causes the double strands to separate, while cooling allows H bonds to reform.

What is the function of DNA Polymerase I?

It removes RNA primers and replaces them with DNA.

What is the importance of PCR in molecular biology?

It revolutionizes the ability to use DNA as a tool for various applications.