Biology 9700/12 May June 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Estimation of spongy mesophyll cell size using stage micrometer scale and eyepiece graticule calibration.

2. Properties of biomolecules: differentiation of branched (amylopectin, glycogen) and unbranched polysaccharides (cellulose, amylose), and bonding in proteins (ionic, hydrogen, disulfide).

3. Enzyme activity: activation energy reduction by catalysts, factors affecting activity (temperature, pH), and substrate interactions.

4. Plant adaptations: xerophytes reducing transpiration via sunken stomata and thick cuticles, phloem sucrose transport via active mechanisms.

5. Respiratory adaptations: alveolar efficiency in gas exchange, nicotine’s effects on cilia and goblet cells, and emphysema's impact on surface area.

6. Nucleic acid processes: transcription by RNA polymerase, hydrogen bonding in DNA base pairing, and amino acid coding sequences in polypeptide synthesis.

7. Disease prevention and impacts: vaccination challenges for TB and malaria, treatment of bacterial diseases like cholera, and anaerobic bacteria effects on soil fertility.

8. Ecosystem components: nitrogen cycle contributions by nitrifying bacteria, ecosystem interactions, and definitions of communities and niches.