Nucleic Acids and DNA Replication

Question 1

What is a nucleotide?

Answer 1

The monomers that make up polynucleotides

Question 2

Describe the structure of DNA?

Answer 2

1. Double stranded and Double Helix
2. Long Polymer Polynucleotide
3. Relatively Simple Structure

Question 3

What is the purpose of DNA?

Answer 3

Carries the Genetic information, triplet codes for amino acids

Question 4

What is the Structure of RNA?

Answer 4

1. Single Stranded
2. Short Polynucleotides

Question 5

What is the purpose of RNA?

Answer 5

Transfers genetic code from DNA to ribosomes in the cytoplasm

Question 6

What bonds form between 2 nucleotides?

Answer 6

Phosphodiester bonds joined via a condensation reaction

Question 7

Describe the Process of semi-conservative replication?

Answer 7

1. DNA Helicase unwinds DNA by breaking the H-Bonds
2. Both strands act as templates
3. Free DNA nucleotides attach by complementary base pairing
4. DNA Polymerase joins nucleotides forming phosphodiester bonds
5. H-Bonds reform
6. DNA is semi-conservative as each new strand and one original strand

Question 8

What is meant by ‘DNA is semi-conservative’?

Answer 8

New DNA is made of one original strand and one new strand

Question 9

How do you prove DNA replication is semi-conservative?

Answer 9

1.Population cultured in a growth medium containing heavy Nitrogen (15N) only.
2. When centrifuged only one heavy band is observed
3. Cells transferred to a medium with only light nitrogen
4. After one replication the DNA band was intermediate (twice the thickness)
5. After 2 replications in light nitrogen, intermediate and light bands were observed
6. Proving DNA replication is semi-conservative