1. a) Egg cells in a mammal are made in the
b) The part of a cell which controls which substances enter and leave is the
cell surface membrane cell wall cytoplasm nucleus
c) Scurvy is caused by the lack of a
carbohydrate mineral protein vitamin
d) The fetus is protected from damage by the
amniotic fluid oviduct placenta ribcage
e) The vertebrates which live on land but which reproduce in water are
amphibians birds fish reptiles
f) The substance made in photosynthesis which stores energy is
carbon dioxide glucose oxygen water
g) In a food chain the type of organism which feeds on a producer is a
decomposer primary consumer secondary consumer virus
h) Fibre is important in a human diet because it
contains vitamins is digested to glucose makes us feel full prevents constipation
i) Iodine solution is used to test plant leaves for
carbon dioxide glucose starch water
j) The dark object in the centre of a stained human cheek cell is the
cell surface membrane chloroplast cytoplasm nucleus
(10)
2.
Homer Simpson likes to eat lots of doughnuts and drink Duff beer. He sits down all day in his office at the Springfield nuclear power plant where he is the Safety Officer. He hates all exercise and spends his free time watching TV.
(a) Suggest three biological reasons why Homer's lifestyle is unhealthy.
(i) (1)
(ii) (1)
(iii) (1)
(b) Suggest two ways in which Homer could improve his lifestyle.
(i) (1)
(ii) (1)
3. This is a picture of a rape plant. It makes seeds which contain liquid fats called oils.
(a) Name two conditions which you would need to give rape seeds so that they could germinate in a laboratory.
Condition 1: (1)
Condition 2: (1)
(b) What is the value to the plant of producing oils in its seeds?
(2)
Scientists have now produced rape plants whose seeds contain a chemical which can be made into a biodegradable plastic. They did this by putting four genes from a bacterium into the nuclei of the rape cells.
(c) What are genes for?
(1)
(1)
(e) Biodegradable plastic would be useful for some purposes, but not for others. Suggest one use for which it would be suitable and one for which it would not be suitable.
Suitable use: (1)
Unsuitable use: (1)
4. Grass flowers make pollen which is carried by air currents. Other plants, such as roses, make pollen which is carried by honey bees.
(a) Which part of a flower makes pollen?
(1)
(b) Suggest two ways in which wind-dispersed pollen might differ from beedispersed pollen.
(i) (1)
(ii) (1)
An experiment showed that pollen carried by the air had travelled up to 475 metres from the flowers whereas pollen carried by bees had travelled up to 4.5 kilometres from the plants.
(c) Ho.w do you think that the scientists were able to show that some honey bee pollen had travelled 4.5 kilometres from the flowers where it was made?
(3)
5. Explain why yeast is used in bread making.
(4)
6. Gerbils are often kept as pets in school science laboratories.
John and Marcia investigated the activity of a school gerbil by placing motionsensing electrodes in the animal's cage. The electrodes were connected to a computer which recorded when the animal was moving around the cage. The results are shown in the chart below. Time is recorded using the 24-hour clock. Midnight is 24 hours and midday is 12 hours.
(a) Use the chart to state when the animal was most active.
(1)
(b) Between what times do you think the animal was asleep?
(1)
This gerbil shows a similar pattern of behaviour to those gerbils living in their natural habitats. Gerbils are herbivores and are vulnerable to attack by predators.
(c) Suggest how this pattern of behaviour could help a gerbil to survive in deserts.
(3)
Gerbils are popular as pets because (unlike mice) they do not produce unpleasant scents. This is partly because they produce very little urine.
(d) How might this behaviour help the gerbils survive in desert habitats?
(2)
7. The diagram shows the reproductive system of the human male.
(a) Mark an X on the diagram to show the place where human sperm cells are made. (1)
A single ejaculation contains millions of sperms, although only one sperm is needed to fertilise an egg.
(b) Suggest why so many sperms are released at a single ejaculation.
(2)
Sperms are ejaculated in a liquid which contains sugars and chemicals which make the sperms swim.
(c) Why is it important that the liquid contains sugars?
(2)
(d) Why is it important that this liquid can make the sperms swim?
(2)
Sperms develop best at a temperature of 29°C, which is lower than the body temperature of 37 °C. The temperatures of the testes are maintained at 29°C.
(e) How many degrees cooler are the testes than the rest of the body?
(1)
(2)
8. Cigarette smoke contains carbon monoxide, a gas which reduces the ability of the blood to carry oxygen.
(a) Name the part of the blood which carries oxygen around the body.
(1)
Athletes who smoke regularly may find that they cannot perform as well as people who do not smoke.
(b) How could carbon monoxide help to cause this problem?
(2)
(c) Name two other effects of cigarette smoke which could cause an athlete to perform badly.
Effect 1: (1)
Effect 2: (1)
9. Describe a habitat which you know. Name and describe some of the producers in the habitat. What other organisms live there and on what do they feed?
(5)