1. Where are coronary arteries found and what is their function ?
Answer
Thay are in the wall of the heart (or in the heart muscle tissue), where they supply glucose and oxygen to the cells of the heart.
2. What is meant by "obesity" ?
Answer
Obesity means very overweight (with a BMI greater that 25).
3. What is the main function of all digestive enzymes ?
Answer
Digestive enzymes convert food into small soluble molecules that can be absorbed into the bloodstream.
4. A student investigates the effect of pH on the rate of reaction of the enzyme amylase. He mixes buffer solution, starch solution, and amylase solution, then places them in a water bath at 35°C. At regular intervals, samples of the reaction mixture are added to iodine solution until the iodine no longer changes colour, showing the starch has been broken down. The investigation is repeated using buffer solutions with pH values from 4 to 9.
a) What is the dependent variable for this investigation ?
b) Give the variables that the student controlled.
c) How did the student control the temperature ? Why it must be controlled ?
Answer
a) Time taken for all starch to break down (no further colour change).
b) Volume of amylase, volume of buffer, volume of starch, time in water bath, number of drops of iodine per well, number of drops of mixture removed at regular intervals.
c) The temperature was controlled using a water bath. Temperature affects the rate of an enzyme-controlled reaction. An increase in temperature would increase the rate. If too cold, rate of reaction will be low or if too hot, enzymes can denature.
5. The figure below shows a cross-section through a human heart. Name the parts labelled A–E.
Answer
6. The heart contains valves to prevent the backflow of blood. Describe the effects a faulty valve would have on a person.
Answer
Less oxygenated blood would be pumped around the body so the person may feel tired, dizzy or breathless.
7. Name the components of the blood labelled A–D in the figure below.
Answer
8. Match the health issues with the disease that the health issue most commonly triggers.
| Health issue | Disease most commonly triggered |
|---|---|
| Immune system defects | Certain cancers |
| Viruses living in cells | Infectious diseases |
| Severe physical ill health | Allergies, such as skin rashes and asthma |
| Immune reactions caused by a pathogen | Depression and other mental illness |
Answer
Immune system defects can lead to infectious diseases.
Viruses living in cells cause certain cancers.
Severe physical ill health cause depression and other mental illness.
Immune reactions caused by a pathogen trigger allergies, such as skin rashes and asthma.
9. What can happen to unborn babies if they are exposed to high levels of alcohol ?
Answer
High levels of alcohol can cause fetal alcohol syndrome, increased risk of miscarriage, premature birth, low birth weight or reduced brain function.
10. List some lifestyle risk factors for cancers that have been identified.
Answer
Smoking, too much alcohol, ionising radiation, obesity, etc.