Cells (Continuity and change)
- Cell and nuclear division
- Cytokinesis
- Animal: actin–myosin ring
- Plant: vesicles build wall
- Unequal: oogenesis, yeast budding
- Before division
- DNA replication: two chromatids
- Histones supercoil DNA
- Microtubules and motors move
- Mitosis
- Prophase, metaphase
- Anaphase, telophase
- Two identical nuclei
- Meiosis
- Diploid to four haploid
- Homologues then chromatids separate
- Crossing over, random orientation
- Non-disjunction
- Trisomy 21
- Down syndrome
- Cell cycle HL only
- G1, S, G2, M, cytokinesis
- Cyclin thresholds at checkpoints
- Meristems, embryos, skin
- Tumours HL only
- Oncogenes, tumour suppressors
- Benign vs malignant
- Metastasis: secondary tumour
- Mitotic index
- Cytokinesis
- Gene expression (HL)HL only
- Gene to phenotype HL only
- Transcription
- Translation
- Protein function
- Regulating transcription HL only
- Promoters
- Enhancers
- Transcription factors
- mRNA degradation HL only
- Nucleases
- Minutes to days
- Epigenesis HL only
- Same genome
- Different transcriptome, proteome
- Phenotype not genotype
- Epigenetic tags HL only
- Promoter cytosine methylation
- Histone methylation
- Inheritance and environment HL only
- Tags kept through division
- Air pollution
- Tigons and ligers
- Monozygotic twins
- External factors HL only
- Oestrogen receptor complex
- Lactose and lac operon
- Gene to phenotype HL only
- Water potential
- Solvation
- Polar water
- Ions attract δ+ or δ−
- Hydrogen bonds with solutes
- Osmosis
- Towards higher solute concentration
- Hypo-, hyper-, isotonic
- Isotonic: dynamic equilibrium
- Plant tissue practical
- Percentage change in mass
- Zero change: isotonic point
- Standard error bars
- No cell wall
- Burst or crenate
- Contractile vacuoles
- Isotonic tissue fluid
- Cell wall
- Turgor pressure
- Plasmolysis
- Medical uses
- Intravenous fluids
- Transplant organs
- Water potential HL only
- ψw = ψs + ψp
- High to low ψ
- Pure water = 0 kPa
- Xylem: negative ψp
- Solvation