1. Describe the function of the heart.
Answer
An organ that pumps blood around the body in a double circulatory system.
2. Explain what is meant by the term "health" and list ways of improving health.
Answer
Health is the state of physical and mental well-being. Health can be improved by: balanced diet, regular exercise, reduced stress.
3. Explain shortly the function of oesophagus, stomach, small intestine and large intestine.
Answer
Oesophagus transports the food to stomach by peristalsis.
Stomach produces the hydrochloric acid.
Small intestine absorbs the soluble products of digestion.
Large intestine absorbs water and mineral ions.
4. The Figure below shows the "lock and key" model of enzyme action. Describe what is happening in parts A to C.
Answer
The enzyme has a specific shape and has an active site specific to one substrate. The substrate fits into the active site like a key in a lock. The enzyme catalyses the reaction and a bond is broken. The products are released from the active site and the enzyme is unchanged.
5. Give two ways that smoking can increase the risk of cardiovascular disease.
Answer
Chemicals in cigarette smoke increase heart rate and blood pressure and damage the lining of the arteries. Fatty material builds up in the coronary arteries, making them narrower. The supply of oxygenated blood to the heart muscle is reduced or sometimes stopped.
6. Explain what happens to the heart in coronary heart disease.
Answer
In coronary heart disease, layers of fatty material build up inside the coronary arteries, narrowing them and reducing the flow of blood, which results in a lack of oxygen for the heart muscle.
7. Describe the structures and functions of arteries, capillaries and veins.
Answer
Arteries have a thick layer of muscle tissue and elastic tissue (or narrow lumen) to maintain and withstand high pressure. They transport blood
away from the heart.
Veins have a wide lumen so less resistance to blood flow and valves to prevent backflow of blood. They transport blood to the heart.
Capillaries have thin walls (only one cell thick) so substances can diffuse into and out of the blood. They exchange materials between blood and cells (or tissues).
8. What is the difference between communicable and non-communicable diseases ?
Answer
Communicable diseases are infectious, non-communicable diseases are not infectious. Communicable diseases are caused by pathogens, non-communicable diseases are not caused by pathogens. Communicable diseases can be transmitted from one person to another, noncommunicable diseases cannot be transmitted.
9. Describe how a person's liver can be affected by drinking too much alcohol.
Answer
The liver may accumulate fat and become enlarged. Prolonged use can lead to liver cirrhosis, resulting in scarring that impairs its ability to function effectively.
10. Give the difference between benign tumours and malignant tumours.
Answer
Malignant tumours invade neighbouring tissues, benign tumours do not. Malignant tumours spread to different parts of the body in the blood, benign tumours do not. Malignant tumours form secondary tumours, benign tumours do not.