Which bases are purines?

  1. Thymine and uracil
  2. Cytosine and thymine
  3. Uracil and cytosine
  4. Adenine and guanine
Answer

D) Adenine and guanine

Purines have a double ring. AS & A Level Biology · Topic 6 Nucleic Acids and Protein Synthesis · 6.1 Structure of nucleic acids and replication of DNA

Biology MCQ · More A Level Biology: Nucleic acids and protein synthesis MCQs · Practise