Biology A (9-1) - Gateway Science Suite J247 9-1: Cell level systems Topical Past Paper Questions

Bacteria are found in milk. They can cause the milk to decompose. Enzymes from the bacteria convert sugar in the milk into lactic acid. Some students investigate the effect of temperature on the decomposition of milk. This is the method the students use: • Pour $ 20\,cm^{3} $ of…

Some students investigate the effect of run-off water from a farm on the growth of plants. The run-off water is washed off the fields in the farm when it rains. They use a pond plant called duckweed, shown in the diagram. A duckweed plant has a single leaf that floats on the surf…

Marimo moss balls are made up of green algae. They are found in lakes and are known to rise and fall during different times of the day. Fig. 17.1 shows some moss balls in a beaker of water. Fig. 17.1 Scientists predict that the moss balls rise because they are covered in tiny bub…