This exam focus covers Exam Focus within DNA Genome for GCSE Biology. DNA structure, function, and the human genome It is section 11 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 11 of 13
Practice
25 questions
Recall
25 flashcards
Exam Focus
Frequently ExaminedDNA and the genome are tested in almost every AQA Biology Paper 2 series. The most common question formats are:
- 1-mark recall: "What is a gene?" or "State the bases that pair together in DNA." Know definitions precisely.
- 2-mark explain: "Explain how the base sequence of DNA determines the structure of a protein." Always mention amino acid sequence and protein shape.
- Application questions: Given a DNA base sequence, identify the complementary strand using A-T and C-G pairing rules.
- 6-mark extended response: "Describe how a protein is made from DNA" — very high frequency. Structure your answer in two clearly labelled stages: transcription (nucleus: DNA unzips → mRNA made → leaves through nuclear pores) and translation (ribosome: codons read → tRNA brings amino acids → peptide bonds form → protein folds). Missing the location of either step costs marks.
- 4-mark explain: "Explain how a mutation could affect an organism." Chain your answer: base change → different codon → different amino acid → different protein shape → loss of function. Award yourself one mark per link in the chain.
Key command words: "State" (give without explanation), "Describe" (list features), "Explain" (give reasons). For base pairing questions, always write both pairs: A-T and C-G. For protein synthesis questions, always state WHERE each stage happens.