Biology 9700/51 Oct Nov 2009 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of temperature effects on the light-dependent stage of photosynthesis, focusing on controlling variables like light intensity and chloroplast suspension concentration.
2. Estimation of cell density in cultures using a counting grid and the importance of control setups for validating growth experiments.
3. Percentage growth calculations and hypothesis testing for a growth-promoting substance, identifying supportive and contradictory evidence from experimental results.
4. Procedures for assessing relative organ size in fish, statistical testing for significance in size variations, and implications of reduced organ size on reproductive success.
5. Analysis of PCB exposure on human sperm DNA integrity using fluorescence markers and plotting DNA fragmentation indices against PCB concentrations.
6. Effects of pollutants like CB-153 on DNA damage trends, highlighting concentration-dependent impacts and conclusions from grouped data analysis.