Unit 1: Cells and multicellular organisms

Cell theory and cell types. States the three postulates of cell theory, contrasts prokaryotic and eukaryotic cells across membrane-bound organelles, genetic material, ribosomes and size, and groups bacteria and archaea as the two prokaryotic domains.

Surface area to volume ratio. Calculates SA:V for simple cubes, shows why it falls as size rises, and links the ratio to limits on diffusion, the typical size range of cells and the structural adaptations of exchange surfaces.

Enzymes. Defines enzymes and the active site, applies the induced-fit model, and predicts the effect of temperature, pH, substrate and enzyme concentration and inhibitors (competitive and non-competitive) on reaction rate.

Cellular components. Describes the plasma membrane using the fluid mosaic model, then names the structure and function of each membrane-bound organelle (nucleus, mitochondrion, chloroplast, ER, Golgi, lysosome, vesicle, vacuole) plus the cytoskeleton and cell wall.

Photosynthesis and respiration. Writes the balanced word and chemical equations for photosynthesis and aerobic respiration, locates each in chloroplasts and mitochondria, and compares anaerobic respiration in animals (lactic acid) and yeast (ethanol).

Membrane transport. Defines diffusion, osmosis (with tonicity), facilitated diffusion and active transport including protein pumps, endocytosis and exocytosis, and predicts the direction and energy requirements for each.

Exchange and transport. Describes gas exchange surfaces in plants (stomata) and animals (alveoli, gills), the cohesion-tension theory of transpiration, the phloem translocation pathway and the differences between open and closed circulatory systems including the human four-chambered heart.

Multicellular hierarchy and stem cells. Lays out the cell to tissue to organ to organ-system progression with named examples and contrasts totipotent, pluripotent and multipotent stem cells across potency and source.