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Question 1

What is the difference between a nucleotide and nucleoside

Answer 1

“A nucleotide is composed of a base, a sugar, and a phosphate group.
A nucleoside is composed of a base and a sugar (no phosphate).
”

Question 2

By convention which direction is the nucleotide sequence given in

Answer 2

5’ to 3’

Question 3

What is the secondary dna structure

Answer 3

Right handed double helix

Question 4

What causes dna strands to dissociate

Answer 4

High heat or low salt concentration

Question 5

What is the lowest level of dna packaging

Answer 5

Nucleosome: dna wrapped around the histones giving x7 condensation

Question 6

What is the second level of dna packaging

Answer 6

30nm fibre giving x40 condensation

Question 7

What is the highest level of dna packaging

Answer 7

Mitosis chromosome: x10000 condensation, 1400nm, fibre folds into loops

Question 8

What is chromatin

Answer 8

Dna and proteins

Question 9

Which carbon does the base attach to

Answer 9

1’

Question 10

What is the difference between t and u

Answer 10

T has an extra methyl group

Question 11

Describe the histones in the nucleosome

Answer 11

Dna is wrapped round 8 histones (2A, 2B, 3,4) and histones 1 is between each nucleosome