lecture 11 - DNA structure Flashcards
What are Chargraff’s rules?
[A]=[T] and [G]=[C] and that the composition of DNA and base concentrations varies between species
What are the two types of DNA/RNA bases?
Purine and pyrimidine
What are the pyrimidine bases?
Cytosine, Thymine
What are the purine bases?
Adenine, guanine
How many ‘rings’ do purine bases have?
2
How many ‘rings’ do pyrimidine bases have?
1
What is the name of the bonds between sugar and phosphate groups in the DNA backbone?
Phosphodiester bonds
What are the names for a long strand of repeating nucleotides?
Polynucleotide, nucleic acid
What carbon is the bonding hydroxyl group of a nucleotide attached to?
3’
What carbon is the phosphate group of a nucleotide attached to?
5’
What needs to happen to the phosphate group of a nucleotide before phosphodiester bonds can be formed?
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
What direction do nucleotides form a chain?
5’ to 3’ - 5’ phosphate build onto the end at a 3’ hydroxyl group.
How many hydrogen bonds exist between the A and T base pair?
2
How many hydrogen bonds exist between the G and C base pairs?
3