Biology 9700/02 Oct Nov 2003 | Cambridge AS Level Past Papers With Mark Scheme

1. Artery and vein comparison: structural differences in wall thickness, lumen diameter, and presence of valves; capillaries' role in gas exchange efficiency in the lungs.

2. Energy flow in ecosystems: trophic energy calculations for primary consumers, efficiency between secondary and tertiary consumers, and decomposers' role in carbon and nitrogen cycling.

3. Cholera infection: caused by Vibrio cholerae, rapid dehydration due to toxin-induced diarrhea, oral cholera vaccine's immune response involving gut lymphocytes and antibody production.

4. Polysaccharide characteristics: distinctions in glycosidic bonds, monomer types, and storage sites for starch, glycogen, and cellulose; amylase hydrolysis rate determination via iodine test and time measurements.

5. Membrane components: glycoproteins' cell signaling roles, carrier proteins in active transport, cholesterol for fluidity; ion and non-polar molecule crossing mechanisms and phagocytosis processes.

6. Athlete oxygen consumption: increased demand during exercise linked to cellular respiration, post-exercise recovery involving oxygen debt repayment and ATP resynthesis; heart treatment methods contrasting transplant rarity with bypass surgery frequency.