(a) Explain why an athlete in a race would be given a glucose drink rather than a piece of bread.
(b) Outline the test for starch in a given food substance.
(c) State five reasons why water is important in human diet.
Explanation
(a)Why an athlete should be given glucose drink: Glucose is the simplest form of carbohydrates/soluble form of carbohydrate; an energy-giving food substance which does not require any form of digestion. – hence it is absorbed in the ileum/small intestine. – where it diffuses/enters into the blood stream/circulatory system. – it is then assimilated; and oxidized. – within the shortest time/quickly/immediately. – to give energy to the athlete. – bread is a complex carbohydrate/polysaccharide/starch. – which will require a series of digestive processes/hydrolysis. – which starts in the mouth; and ends in small intestine/ileum. – this takes a longer time to produce energy for use/cannot give immediate energy.
(b) Test for starch: –
- Macerate/crush a piece of the food substance.
- add water to the crushed food to form a solution/suspension/take a piece of food substance.
- put a few drops of the solution/suspension/ piece of food.
- on a white tile/watch glass/in test tube
- add one or two drops of iodine solution
- the solution/piece of food will turn blue black
- indicating the presence of starch.
(c) Importance of water in human diet: –
- Water is an essential part of living protoplasm; blood
- it acts as a solvent; and transport medium in the body for food substances/gases/hormones.
- transports waste excretory products
- it is a medium for chemical reactions/digestive processes
- it function in distribution of body heat
- it is the main component of the synovial fluid of joints; amniotic fluid
- serves a protective function in the brain
- allows easy movement of food through the digestive tract.