1. Define digestion and name the three main types of digestive enzymes.
Answer
Digestion is the breakdown of large, insoluble food molecules into smaller, soluble molecules. The main digestive enzymes are carbohydrase, protease and lipase.
2. Explain how stents are used to treat coronary heart disease.
Answer
A stent is a wire mesh that can be inserted into a coronary artery to keep it open so more blood can flow through.
3. Describe how cell division can result in cancer.
Answer
Cancer is the result of changes in cells that lead to uncontrolled growth and division. Malignant tumours are formed and they can spread from one part of the body to another.
4. Amylase (carbohydrase), lipase and protease are digestive enzymes. Show the substrates of amylase and protease, and the products of lipase and protease.
Answer
The substrate of amylase is starch and the substrate of protease is protein. The products of lipase are are fatty acids and glycerol, while the products of protease are amino acids.
5. The figure below shows the human breathing system. Name the parts labelled A–E.
Answer
6. Give the functions of the left and right ventricles of the heart.
Answer
Left ventricle pumps blood around the body. Right ventricle pumps blood to the lungs where gas exchange takes place.
7. Describe some risks associated with heart or heart-and-lung transplants.
Answer
The transplant may be rejected, patient needs to take immunosuppressant drugs to prevent rejection, waiting lists for donor can be very long, there is a risk of (viral) infection from the donor heart or from the operation.
8. Name the substances transported by the blood plasma.
Answer
Glucose, amino acids, lactic acid, mineral ions, vitamins and hormones.
9. Name some diseases that obesity is a risk factor for.
Answer
Cardiovascular diseases and cancer.
10. Carcinogens are chemicals or agents that can cause cancer by damaging DNA. Give some examples of carcinogens.
Answer
X–rays, some UV light, tar in cigarette smoke, asbestos, etc.