Biology GCSE Past Paper 2

Some organisms have adaptations that allow them to survive in very cold conditions.

1. The photograph below is of a polar bear. Polars bears live in the Arctic. The conditions here are very cold. Provide two ways in which a polar bear has adapted to living in these very cold conditions and explain how this adaptation helps them to survive.

Adaptation 1 ___________________________________________________

How it helps the polar bear survive cold conditions

______________________________________________________________________________________________________________________________________________

Adaptation 2 ____________________________________________________

How it helps the polar bear survive cold conditions

______________________________________________________________________________________________________________________________________________

2. Zebras live in the hot plains for Africa. Their main predators are lions and hyenas. Suggest two adaptations that help zebras avoid being caught and killed by these predators and explain how the adaptations helps them with this goal.

Adaptation 1 ___________________________________________________

How it helps the zebra escape predators

______________________________________________________________________________________________________________________________________________

Adaptation 2 ____________________________________________________

How it helps the zebra escape predators

______________________________________________________________________________________________________________________________________________

2. The menstrual cycle involves a number of hormones.
   1. Describe the roles of the following hormones in the menstrual cycle.
      1. FSH
      2. LH
      3. Oestrogen
   2. Hormones are used in oral contraceptives to prevent women from becoming pregnant during sexual intercourse. Complete the sentences using the correct hormone listed below.
      1. The hormone most likely to be found on oral contraceptives is ______________.
      2. The hormone most likely to be used in fertility treatments is ______________.

oestrogen LSH LH

3. Cystic fibrosis is an inherited disorder that mainly affects the lungs. It’s a chronic illness and as yet there’s no real cure.
   1. A couple have two children. The father has cystic fibrosis while the mother is healthy. They have a boy and a girl. The boy is healthy but the girl has cystic fibrosis.
      1. Explain why the girl has cystic fibrosis.
      2. Why didn’t the boy inherit cystic fibrosis?
   2. The couple know that there’s a risk that their next child will inherit cystic fibrosis. It is possible for an embryo to be screened for the disease. Some people support embryo screening however others do not.
      1. Provide one reason why some people support embryo screening.
      2. Provide one reason why some people do not support embryo screening.

4. The table below shows three different species of plant, A, B and C. It provides information on the average number of stomata on the upper and lower surfaces of the leaves rounded up to 2 sf.
   1. 1. Which of the plant species probably lives in a dry region?
      2. Explain your answer.
   2. All three species in the table have more stomata at on the lower surface as opposed to the upper surface of their leaves. Explain how this could help a plant survive better.

5. A lot of people use different recreational drugs. Some recreational drugs are legal and some are illegal.
   1. Provide an example for each of the following:
      1. a legal recreational drug
      2. an illegal recreational drug
   2. Some drugs are addictive. How a drug acts within the body to make someone become addicted to it.
   3. Scientists have been researching a lot into the affects of cannabis and mental health. An investigation was carried out into cannabis smoking and depression. The results are shown in the table below. Provide two conclusions that can be taken from this data.
      1. _________________________________________________________
      2. _________________________________________________________

ANSWERS

1. Whatever adaptation you give remember to make sure that it links with the advantage.
   1. 1. Thick hair/fur for insulation.
      2. Small ears to reduce heat loss.
      3. White fur for camouflage.
      4. Thick layer of fat insulates/keeps the bear warm.
   2. 1. Long legs for speed/to escape.
      2. Striped body for camouflage.
      3. Eyes on the side of its head so that it has a wider field of vision.
      4. Large ears so that it can hear the predators better.

2. 1. Check the number of marks. For example, if there are four marks then you need to give four points. However, make sure you give examples for all the hormones. Although it says describe keep your descriptions brief and to the point.
      1. FSH stimulate the eggs to mature AND/OR stimulates oestrogen production.
      2. Oestrogen stimulates LH production AND/OR inhibits FSH production.
      3. LH stimulates egg release.
   2. 1. Oestrogen (it inhibits the production of FSH which in then prevents the eggs from maturing in the ovaries)
      2. FSH (it stimulate the eggs to mature in the ovary)

3. 1. You know that cystic fibrosis is a recessive allele. This means that to inherit cystic fibrosis the child must have two recessive cystic fibrosis alleles.
      1. Correct: The girl inherited two recessive/cystic fibrosis/diseased alleles from both her parents.

Incorrect: There’s no need to mention chromosomes.

2. Correct: The boy inherited the dominant/normal allele from his mother.

Incorrect: No points are given for mentioning the father’s recessive allele.

2. Remember that you only have to provide one reason.
   1. Correct:
      • It reduces the number of people in the population who have cystic fibrosis.
      • It reduces health-care costs.
      • It’s expensive to bring up a child with cystic fibrosis.
      • It allow people to decide whether they want to terminate the pregnancy/have an abortion.
      • It helps the couple to begin to prepare emotionally and financially if they decide to have the child.
   2. Correct:
      • It could possibly damage/hurt the embryo/foetus/baby.
      • Screening is expensive.
      • There are ethical/moral/religious decisions involved.
      • Everyone has a right to life.

Incorrect: Simply stating that’s unethical, immoral or not natural won’t get you a mark.

4. 1. 1. B
      2. Correct: B has the lowest number of stomata. This means that less water can be lost via the stomata by transpiration/evaporation.

Incorrect: This has nothing to do with leaf surface area.

2. Remember to check the number of marks available.

Correct:

• It reduces the amount of water lost/transpiration from the upper surface.
• The upper surface is warmer/the lower surface is shaded so there’s less light/heat.

Incorrect: You can’t say that no water is lost because there’s always some water loss.

5. 1. 1. Correct:
         • Tobacco
         • Alcohol
         • Nicotine

Incorrect:

• Cigarettes: you need to provide the drug (tobacco or nicotine).
• Coffee: it’s not classed as a recreational drug.

Correct: It alters the body’s chemistry.

Incorrect:

• It has nothing to do with withdrawal symptoms or craving.
• Any non-chemical effects won’t get you a mark.

Correct:

• An increase in cannabis use/smoking increases depression.
• There’s been a greater effect in women.
• Depression is linked with cannabis but there’s no direct cause shown from these results.
• Not all of the cannabis smokers develop depression.

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