DNA Synthesis, Mutation, Repair and Antioxidants

DNA Synthesis

1. Define conservative and semiconservative replication.

2. Explain the difference between uni- and bi-directional replication.

3. List the differences and the similarities between leading and lagging strand synthesis.

4. Define the terms primer and template.

5. List the major eukaryotic DNA polymerases and state their function(s).

6. List the cis- and trans- acting factors required for initiating and sustaining DNA replication.

7. Describe how leading and lagging strand synthesis are coordinated.

8. State the function of Telomerase and describe its "probable" mechanism.

9. List some examples of drugs that inhibit replication and explain how they "inhibit" replication.

DNA Mutation and Repair

1. Define the following mutations: point, silent, missense, nonsense and frameshift.

2. Define the terms transition and transversion.

3. Describe what is meant by a conservative and nonconservative mutation.

4. List five major ways that DNA can be damaged or mutated.

5. Outline the major steps of mismatch , nucleotide excision and recombination repair.

6. Outline the pathway by whichp53 is believed to regulate DNA repair.

7. List four diseases that are attributed to defects in DNA repair.

Antioxidants (Cobalamin and Folic Acid)

1. Identify the major active oxygen (AO) species and compare their relative reactivities.

2. Explain how the following AO species are generated intracellularly:

Singlet Oxygen

Superoxide Anion Radical

Lipid Peroxyl Radical

Hydroxyl Radical

3. List the harmful actions of AO species in cells.

4. Explain how vitamins C, E and the carotenoids act as cellular antioxidants.

5. Discuss the deficiencies, toxicities and RDA for vitamins C, E and the carotenoids.

6. Explain how folate is absorbed and transported.

7. Diagram the function, source, and deficiencies of folic acid and vitamin B₁₂ (cobalamin).