Water and carbohydratesEdexcel International A Level Biology: Mind map

Exam questions on Water and carbohydrates

1. Blood plasma is about 90% water. It carries dissolved glucose, amino acids and mineral ions such as hydrogencarbonate ions (HCO₃⁻) around the body of a mammal.
   Explain how the structure of glucose allows it to dissolve in blood plasma so that it can be transported.2 marks
2. A marathon runner stores energy as glycogen in her liver and muscle cells. During a race, the glycogen is broken down to provide glucose for respiration.
   Explain why glycogen is a suitable energy store for the runner's muscle cells.2 marks
3. Potato tuber cells store starch over the winter. In spring the tuber must release glucose quickly to supply energy for the growth of new shoots. Starch is a mixture of two polysaccharides, amylose and amylopectin.
   Compare the structures of amylose and amylopectin.3 marks