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 explain what semiconservative replication means and sketch it for two rounds. (Guide: “Semiconservative replication”, Figure 1)
- I can explain why new DNA is always made 5′ → 3′ and why DNA polymerase needs an RNA primer. (Guide: “The direction rule”; Practice Q7)
- I can state the job and position of helicase, topoisomerase, DNA polymerase and ligase. (Guide: “At the replication fork”; Practice Q1, Q4)
- I can explain why the leading strand is continuous and the lagging strand is made in fragments. (Guide: “Leading and lagging strands”, Figure 2; Practice Q4)
- I can describe what happens to RNA primers and how the lagging strand is completed. (Guide: “Leading and lagging strands”)
Calculation and skills
- I can write the new strand made on a template, 5′ to 3′, and say which new strand at a fork is leading. (Guide: Worked example 1; Practice Q3)
- I can predict the density bands, or the percentage of labelled molecules, for each replication model. (Guide: Worked example 2; Practice Q2)
- I can calculate replication time from fork speed, genome size and number of origins, remembering two forks per origin. (Guide: Worked example 3; Practice Q6)
Reasoning
- I can explain how density data rule out the conservative and dispersive models. (Guide: “The evidence”; Worked example 2)
- I can identify a defective enzyme from experimental observations and justify my answer. (Practice Q5)
- I can predict the effect of blocking primers, ligase or topoisomerase on each strand. (Practice Q4, Q5, Q7)
- I can explain why eukaryotic chromosomes need many origins of replication. (Guide: Worked example 3; Practice Q6)
All ticked? Move on to Topic 6.3, Transcription and RNA Processing, or return to the course roadmap.