A-Level Biology | Fun Learning Quest for Kids

You are comparing the efficiency of gas exchange in a single-celled amoeba and a human. Which of the following best explains why the amoeba can rely solely on diffusion across its cell surface membrane, whereas a human requires specialised exchange surfaces like alveoli?

In a laboratory, you are investigating the effect of pH on the activity of the enzyme pepsin, which breaks down proteins in the stomach. You measure the rate of product formation at various pH values. Which graph shape would you expect for pepsin activity over a pH range from 1 to 8?

While studying cell structure under an electron microscope, you observe a cell with a thick peptidoglycan cell wall, no membrane-bound organelles, and a single circular chromosome located in a region without a nuclear envelope. How would you classify this cell?