Genetic information must be copied, read and passed on. This SL lesson covers D1.1 DNA replication, D1.2 Protein synthesis, D1.3 Mutation, D2.1 Cell & nuclear division and D2.3 Water potential.
You will follow replication, transcription and translation, and use codon and water-potential calculations.
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.
DNA is copied semi-conservatively: the double helix unwinds (helicase), and each strand acts as a template. DNA polymerase adds complementary nucleotides (A-T, G-C).
Each daughter molecule keeps one original strand and gains one new strand — the basis of genetic continuity.
Genes are expressed in two stages:
The genetic code is a triplet code, degenerate (most amino acids have several codons) and nearly universal — evidence of shared ancestry.
A mutation is a change in the DNA base sequence. A point mutation changes one base; insertions or deletions can cause a frameshift.
Mutations are the ultimate source of new alleles and genetic variation — the raw material for evolution. Mutagens (UV, some chemicals) raise the mutation rate.
The cell cycle is interphase (growth and DNA replication) then division. Mitosis produces two genetically identical diploid daughter nuclei for growth and repair.
Meiosis (covered under reproduction) halves chromosome number to make varied gametes.
Uncontrolled mitosis, from mutations in genes controlling the cell cycle, can lead to a tumour.
Sort each statement into the correct process.
Match each term to its correct description.
D1.1: semi-conservative replication conserves genetic information
D1.2: transcription (mRNA) then translation (codons, tRNA) make proteins
D1.3: mutation changes the base sequence and creates variation
D2.1 / D2.3: mitosis gives identical diploid cells; Ψ = Ψs + Ψp
Press Finish to see your score.
You have worked through Theme D: Continuity & Change — Molecules & Cells for IB Diploma Biology. 🎉
Your stars: 0 / 0
Next: test yourself in the Evaluate stage Confidence Quiz, then lock it in with Verify.