Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can name the three parts of a nucleotide and say which carbon of the sugar carries the phosphate and which carries the base. (Guide: “The nucleotide: three parts”, Figure 1; Practice Q4)
- I can explain why the information in a nucleic acid is carried by the order of its bases, not by the backbone. (Guide: “Information written in a chemical alphabet”)
- I can explain what the 5′ and 3′ ends of a strand are and why new nucleotides are added only to the 3′ end. (Guide: “Building a strand”; Practice Q7)
- I can describe DNA as an antiparallel double helix, with A–T and C–G pairs held by hydrogen bonds and backbones held by covalent bonds. (Guide: Figure 2; Practice Q2, Q6)
- I can state three structural differences between DNA and RNA. (Guide: “DNA and RNA compared”; Practice Q1)
Calculation and skills
- I can write a complementary DNA or RNA sequence from 5′ to 3′ with both ends labelled. (Guide: Worked example 1; Practice Q2, Q7)
- I can find all four base percentages in double-stranded DNA from one of them. (Guide: Worked example 2; Practice Q3)
- I can count hydrogen bonds between strands and covalent links within a strand. (Guide: Worked example 3; Practice Q6, Q7)
- I can identify the parts and the 5′ and 3′ ends on a diagram of a strand, and say whether it shows DNA or RNA. (Guide: Figures 1 and 2; Practice Q4)
Reasoning
- I can use base composition data to decide whether a sample is DNA or RNA and whether it is likely to be single- or double-stranded. (Guide: Worked example 2; Practice Q5)
- I can explain why strands rich in C–G pairs need more energy to separate, and why heating does not break the backbone. (Guide: Worked example 3; Practice Q6)
- I can predict the effect of a nucleotide that lacks a 3′ –OH on the synthesis of a new strand. (Practice Q7)
All ticked? Move on to Topic 1.7, Proteins, or return to the course roadmap.