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 ▸How can genetic engineering be used in forensic science and paternity tests?
What is the founder effect? How can it influence the genetic profile of a population?
How does muscle contraction work?
How is air breathed in to the lungs so that oxygen reaches the gas exchange surfaces?