2.6 Structure of DNA and RNA

Question 1

Nucleotide components

Answer 1

1. Sugar (pentose)
2. Phosphate (negatively charged, acidic)
3. Nitrogenous base (purine/pyramidine, N)

Linked by covalent bonds

Question 2

Which components of nucleotides form the backbone?

Answer 2

Sugar - phosphate strong backbone

Question 3

DNA vs RNA composition

Answer 3

Question 4

DNA vs RNA nucleotide

Answer 4

Question 5

Detailed DNA structure

Answer 5

• base linked to C1
• phosphate linked to C5
• phosphate of another nucleotide linked to C3 - 3’ terminal end
• pentose of another nucelotide linked to phosphate on 5’ terminal end
• strands are parallel but run in different directions - antiparallel
• complemenatry base pairing
• double helix

Question 6

DNA structure discovery

Answer 6

• discovered using DNA model building by Watson and Crick
• X-ray crystallography - X-ray diffraction patterns used to obtain images by Rosalind Franklin