AS & A Level Biology (9700) — May–June 2025, Paper 41

Name two energy-rich molecules that enter a respiration pathway to synthesise ATP.

Fig. 2.2 shows a respirometer set up to measure the rate of respiration of woodlice. The apparatus includes NaOH pellets, a boiling tube, and a graduated capillary tube with a…

Porphyria is a group of inherited diseases. Three types of porphyria are X-linked protoporphyria, variegate porphyria and congenital erythropoietic porphyria (CEP). Fig. 3.1 shows…

Scientists have developed a new process called artificial photosynthesis. Fig. 4.1 shows the process of artificial photosynthesis. In this process, solar panels capture light…

Geospiza fortis is one of the many species of finch that live on the Galápagos islands. Scientists measured the bill size (length, width and depth) of individuals in a population…

In the kidney, various molecules move between the blood and the kidney nephron. Table 6.1 describes the movements of molecules at three regions of the nephron, P, Q and R: - P:…

Insulin is an example of a cell-signalling molecule of the endocrine system. Outline why insulin can be described as an example of a cell-signalling molecule of the endocrine…

The presence of gibberellins in a plant cell leads to the expression of genes involved in stem elongation. Describe how gibberellin causes stem elongation in plants.

A species is classified into one of three domains. Two of the domains contain only prokaryotic species. With reference to the two prokaryotic domains, describe the features used…

During the course of an action potential, the potential difference across a neurone membrane changes. Table 10.1 shows the potential difference across the neurone membrane at…