Unit 1 Topic 1: Structure Of DNA

Question 1

Describe the structure of a nucleotide

Answer 1

DNA= Deoxyribonucleic Acid
A DNA molecule is made up of 2 chains of nucleotides.
Each nucleotide contains a base, Deoxyribose Sugar (Sugar) and Phosphate

Question 2

Describe the complementary base pairing in DNA

Answer 2

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

Adenine - Thymine
Cytosine - Guanine

These are known as complementary base pairs.

Question 3

Describe the different bonds found in the DNA double helix

Answer 3

Covalent - Connects between the Phosphate of one nucleotides to the sugar of another.

Hydrogen - Connects the complementary base pairs

Question 4

Explain how carbons are numbered on a sugar in a nucleotide

Answer 4

There are 5 different carbons in the deoxyribose sugar, these are numbered in a specific order.
1’
2’
3’
4’
5’
These form the strand called the 3’ 5’ strand.

Question 5

Explain the term “anti-parallel strands”

Answer 5

The two nucleotide chains run in opposite directions from each other. So are called anti-parallel strands.
One strand goes from 5’ to 3’ and the complementary strand goes from 3’ to 5’
The 5’ is positioned at the Phosphate end.
The 3’ is positioned at the Deoxyribose end.