Question

1. In your own words, describe the process of DNA replication (include the proteins discussed in the lecture presentation in your description and identify their functions) (20pts)

2. Is DNA conservative or semiconservative? Explain. (10 pts)

3. In your own words, provide a detailed description of how DNA is packaged in the nucleus (10 pts).

4. Identify the process and detail the steps of transcription from start to finish (In your own words) (10pts)

5. RNA is derived from DNA by what process and which major enzyme? (5pts)

6. List three differences between RNA and DNA. (5pts)

7. What is the difference between Mitosis and Meiosis? (The process and cell types.) (10pts)

8. What is a nonsense mutation? (5 pts)

9. What determines if a gene is functional (5 pts)

10. How do mutations occur in cells? Further list 3 things that can increase the rate of mutations not discussed in lecture. (10 pts)

Answer 1

List three differences between RNA and DNA.

DNA.	RNA
Deoxyribonucleic acid It is located in the nucleus and in the mitochondria double stranded molecule long chain of nucleotides self-replicating base pairing occurs between G and C, A and T	Ribonucleic acid located in cytoplasm, nucleus and mitochondria. single stranded molecule short chain of nucleotides do not replicate,they replicate from DNA base pairing occurs between G and C, A and U

What is the difference between Mitosis and Meiosis?

Mitosis

Meiosis

Occurs in the somatic cells of both asexually and sexually reproducing organisms DNA replication, chromosomes duplication and cell division occur only once. Prophase is simple and brief. Synapsis,crossing over,chiasmata formation and recombination absent. Is an equational division. Two daughter cells are formed at the end. Daughter cells will have the same parental chromosomal number. New gene combinations do not appear. Daughter cells are genetically and metabolically identical to each other and also to the parent cell. Maintains genetic constancy.

Occurs only in the germinal cells of sexually reproducing organisms. DNA replication and chromosome duplication occur once but cell division occurs twice. Prophase 1 is complex and prolonged. Synapsis,crossing over,chiasmata formation and recombination present. Is a reductional division Four daughter cells are formed at the end. Daughter cells will have half the parental number of chromosomes New gene combinations appear. Daughter cells are not identical to each other and also to the parental cell. Creates genetic variability through new gene combinations.

What is a nonsense mutation?

Mutation that changes a codon in a gene to one of the three termination codon (UAA,UGA ,UAG) is decribed as nonsense mutation.It results in the shortened protein because the translation of the mRNA stops at this termination codon.

Is DNA conservative or semiconservative? Explain.

DNA replication occurs through semi-conservative replication.

When Watson and Crick worked out the double helical structure of DNA in 1953, they recognized the complimentary nature of strands- A paired with T and G paired with C.If the two strands of a parental DNA double helix are separated and each of the parental strands then act as template strand to synthesis  a complementary daughter strand .This model of replication , in which a parental duplex DNA gives rise to two identical daughter duplexes DNA, each containing one original parental strand and one new strand, which is called as semiconservative replication.