State the name of one mineral ion needed for chlorophyll production.
Two test-tubes were prepared together. Both contained algae and hydrogencarbonate indicator. At the start of the investigation, the indicator in both tubes was red. One test-tube was kept in darkness and the other was kept in light. After 20 minutes, the contents of the tube in darkness were yellow, while those in the light were purple. Explain why these results were obtained.
Fig. 4.1 is a graph showing how light intensity affects the rate of photosynthesis. State which factors could be limiting the rate of photosynthesis at X and at Y in Fig. 4.1.
State the name of the tissue that moves sucrose around the plant and the name of one other biological molecule moved in this tissue.
Describe how starch is digested in the human digestive system so that the glucose produced can be absorbed into the blood.