Which statement describes how the two strands of a DNA molecule are held together?
Strong hydrogen bonds link identical bases on opposite strands.
Weak hydrogen bonds link complementary bases on opposite strands.
Weak hydrogen bonds link sugar molecules on opposite strands.
Strong hydrogen bonds link phosphate groups on opposite strands.
44 exam-style questions on Edexcel GCSE Biology 3.2 DNA and protein synthesis, covering 3.2.1 DNA structure as a polymer, 3.2.2 Genome and gene definitions, 3.2.3 Extracting DNA from fruit, 3.2.4 Base order determines protein shape, 3.2.5 Stages of protein synthesis, 3.2.6 Non-coding DNA variants affecting phenotype, and 3.2.7 Coding DNA variants affecting phenotype. Each one has a worked solution and a mark scheme showing where the marks go.