Nucleic Acids

Question 1

Structure of a nucleotide

Answer 1

1) Sugar
2) Phosphate
3) Base

Question 2

ATP

Answer 2

Universal energy currency
3 phosphate groups, ribose sugar and the base adenine.
To release energy the bond between the 3rd and 2nd phosphate group is hydrolysed, creating ADP.
every molecule of energy hydrolysed produces 30.6kj

Question 3

Advantages of using ATP

Answer 3

Involves a single reaction
Only one enzyme is needed
releases energy in small amount when and where it is needed
provides a common source of energy for many different reactions, increasing efficiency and control by the cell.

Question 4

Role of ATP

Answer 4

1) Metabolic processes- building large complex molecules from smaller ones eg DNA Synthesis from Nucleotides.
2) Active Transport
3) Movement eg muscle contraction
4) Nerve transmission - sodium potassium pump (active transport)
5) Secretion - packaging and transport of secretory products in vesicles.

Question 5

Structure of DNA

Answer 5

2 polynucleotide strands wound around a double helix
Pentose sugar is deoxyribose
4 organic bases - adenine, thymine, cytosine and guanine
Cytosine and Thymine are pyrimidines
Guanine and adenine are purines
Sugar- phosphate backbone