Biology 9700/04 May June 2002

1. Photophosphorylation: occurs in thylakoid membranes; light energy excites electrons, driving ATP and NADPH production in non-cyclic pathways, with cyclic photophosphorylation recycling electrons through PSI.

2. Respiratory quotient (RQ): indicates substrate usage; RQ > 1 suggests anaerobic respiration, RQ < 1 indicates lipid metabolism. Germinating seeds' oxygen uptake measured via manometer adjustments.

3. Axonal transmission: Na\\(^+\\) influx depolarizes membranes, K\\(^+\\) efflux repolarizes; myelin sheath enhances conduction speed by insulating axons and enabling saltatory conduction.

4. Kidney physiology: glomerulus filters blood, peritubular capillaries reabsorb nutrients, and vasa recta maintains medullary osmotic gradients; collecting ducts regulate water reabsorption via ADH.

5. Pea plant genetics: 9:3:3:1 dihybrid cross ratio explained by independent assortment of R/r and B/b alleles; chi-squared test confirms hypothesis of Mendelian inheritance.