Biology 9700/23 Oct Nov 2019 | Cambridge AS Level Past Papers With Mark Scheme

1. Structure and function of hemoglobin, including the impact of mutations in the HBB gene on protein structure, oxygen transport, and carbon dioxide interaction.

2. Analysis of cell cycle stages in Allium cepa root meristematic tissue, calculation of percentages for cell stages, and time spent in anaphase during the cell cycle.

3. Differences between drought-tolerant and non-tolerant tomato plants, focusing on stomatal aperture, transpiration rates, and water uptake, with the role of microRNAs in protein synthesis regulation.

4. Structural adaptations of arteries, functional differences between arterioles and capillaries, and the formation and return of tissue fluid to the circulatory system.

5. Influenza virus structure and its interaction with host cells, immune response mechanisms for antibody production, and the benefits and drawbacks of artificial passive immunity.

6. Components of the cell surface membrane in squamous epithelial cells, identification of external membrane surfaces, and the roles of membrane proteins and lipids.