Biology 9700/22 May June 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Identification of mitotic stages (prophase, metaphase, anaphase) in onion root tip cells, differences in cell size during division, and active processes in interphase.

2. Ecological terms analysis: habitat, ecosystem, niche, and population, with trophic levels and energy loss explanations in food chains.

3. Red blood cell adaptations for oxygen transport, lifespan limitations due to enzyme loss, and hemoglobin breakdown into iron and amino acids.

4. Role of carbon dioxide and hydrogen ions in oxygen unloading from hemoglobin, including enzyme involvement and Bohr effect mechanisms.

5. Tuberculosis pathogen structure, magnification calculation, prokaryotic cell features, factors influencing TB cases, and streptomycin’s inhibitory effects on bacterial ribosomes.

6. Structural and functional differences between triglycerides and phospholipids, with phospholipid roles in membrane fluidity and selective permeability.

7. Lipase activity investigation using olive oil, pH changes during triglyceride hydrolysis, and enzyme-substrate interaction effects.

8. Nicotine's cardiovascular effects, such as increased heart rate and atherosclerosis risk, and evaluation of low-nicotine tobacco products in harm reduction strategies.