The molecular machinery of inheritance is remarkably precise. This HL lesson covers D1.1 DNA replication, D1.2 Protein synthesis and D1.3 Mutation & gene editing in depth.
You will study leading and lagging strands, translation in detail, mutation types and CRISPR gene editing.
Work through each screen, answer the questions as you go (some are wordy, some are calculations) and collect ⭐ stars. Press Start when you are ready.
Replication is semi-conservative. Helicase unwinds the helix; because DNA polymerase only builds in the 5→3 direction:
Primase lays RNA primers; polymerase proofreads to keep the copy accurate.
Transcription: RNA polymerase makes mRNA from a DNA template.
Translation at the ribosome has three phases — initiation, elongation and termination. tRNAs, activated with their amino acids, read codons via anticodons; the ribosome forms peptide bonds. Several ribosomes can read one mRNA as a polysome.
Mutations change DNA: substitutions (point mutations, e.g. sickle-cell), and insertions/deletions that cause a frameshift. Mutagens raise the rate.
CRISPR-Cas9 is a guided nuclease that cuts DNA at a chosen sequence, allowing precise gene editing — powerful but ethically debated.
Sort each item into the correct category.
Match each replication term to its description.
D1.1 (HL): semi-conservative; leading (continuous) vs lagging (Okazaki) strands; ligase
D1.2 (HL): transcription then translation (initiation, elongation, termination); polysomes
D1.3: substitution, frameshift, mutagens; CRISPR-Cas9 gene editing
Skills: Chargaff ratios; codons = nucleotides / 3
Press Finish to see your score.
You have worked through Theme D: Continuity & Change — Molecules for IB Diploma Biology. 🎉
Your stars: 0 / 0
Next: test yourself in the Verify stage.