lecture 11 - DNA structure

Question 1

What are Chargraff’s rules?

Answer 1

[A]=[T] and [G]=[C] and that the composition of DNA and base concentrations varies between species

Question 2

What are the two types of DNA/RNA bases?

Answer 2

Purine and pyrimidine

Question 3

What are the pyrimidine bases?

Answer 3

Cytosine, Thymine

Question 4

What are the purine bases?

Answer 4

Adenine, guanine

Question 5

How many ‘rings’ do purine bases have?

Answer 5

2

Question 6

How many ‘rings’ do pyrimidine bases have?

Answer 6

1

Question 7

What is the name of the bonds between sugar and phosphate groups in the DNA backbone?

Answer 7

Phosphodiester bonds

Question 8

What are the names for a long strand of repeating nucleotides?

Answer 8

Polynucleotide, nucleic acid

Question 9

What carbon is the bonding hydroxyl group of a nucleotide attached to?

Answer 9

3’

Question 10

What carbon is the phosphate group of a nucleotide attached to?

Answer 10

5’

Question 11

What needs to happen to the phosphate group of a nucleotide before phosphodiester bonds can be formed?

Answer 11

The 3 phosphate group of the nucleotide is cleaved by an enzyme, leaving 1 phosphate group that can then bond to a 3’ hydroxyl group

Question 12

What direction do nucleotides form a chain?

Answer 12

5’ to 3’ - 5’ phosphate build onto the end at a 3’ hydroxyl group.

Question 13

How many hydrogen bonds exist between the A and T base pair?

Answer 13

2

Question 14

How many hydrogen bonds exist between the G and C base pairs?

Answer 14

3