How are polynucleotide DNA strands held together? (3 marks)

The two antiparallel strands of DNA are held together by hydrogen bonds joining the bases of each complementary nucleotide; Adenine is held to Thymine by 2 hydrogen bonds, and Guanine to Cytosine by 3 hydrogen bonds.

SA

Related Biology A Level answers

All answers ▸

Explain how the human body is adapted for gas exchange


Describe what happens when an action potential reaches an axon terminal.


What is the difference between DNA and RNA?


How does Acetylcholine act on a neuronal synapse, and how is it re-uptaken?