Edexcel GCSE Combined Science Paper 2: Biology 2 Higher June 2022 question paper 1SC0/2BH

Figure 1 shows xylem and phloem from the stem of a plant.

Living cells in phloem use energy to transport sucrose.

Which organelles release energy in living cells?

Describe two features of the structure of xylem vessels that can be seen in Figure 1.

A scientist investigated how the flow of air affected the rate of transpiration in a plant.

A fan was used to change the flow of air.

The volume of water taken up by the plant was measured.

Figure 2 shows the results of this investigation.

Explain why switching on the fan caused a change in the volume of water taken up by the plant.

Give one reason why the volume of water taken up by the plant was also measured when the fan was not switched on.

Calculate the rate of water uptake from 8 minutes to 10 minutes when the fan was switched on.

Use the equation

_........ mm³ per minute

Figure 3 shows a cross-section of an artery and a vein.

(Source: © The University of Kansas Medical Center)

Figure 3

Explain one difference between the artery wall and the vein wall shown in Figure 3.

Name one structure that is found in veins but not found in arteries.

A human body has 5 dm³ of blood.

At rest 20% of the blood travels to the muscles.

During exercise 60% of the blood travels to the muscles.

Calculate the volume of blood travelling to the muscles during exercise.

Explain one reason why there is an increase in blood flow to muscles during exercise.

Figure 4 shows a cross-section of a root nodule on a leguminous plant.

Bacteria in the root nodule provide the leguminous plant with nitrogen compounds.

The leguminous plant provides the bacteria with sugars.

(Source: © Nigel Downer / Science Photo Library)

Figure 4

Which term describes the relationship between this leguminous plant and the bacteria?

The width of this root nodule is 7.5 mm.

Give the width in µ m.

Figure 5 shows part of the nitrogen cycle.

Identify the types of microorganism involved in process X and process Y.

Explain how crop rotation increases nitrate levels in the soil.

Explain why increased nitrate levels in the soil improve crop yield.

The combined contraceptive pill contains artificial versions of oestrogen and progesterone.

Explain how the combined contraceptive pill prevents pregnancy.

When taken correctly, the combined pill can be over 99% effective.

Taking the combined pill can lead to weight gain.

Give one other disadvantage of using the combined pill as the only method of contraception.

Excessive weight gain and obesity increase the likelihood of developing type 2 diabetes.

Explain the effect of type 2 diabetes on the body.

A woman had unexplained weight loss and fatigue. She had blood tests to investigate the cause of these symptoms.

Figure 6 shows the results.

Comment on the results of these blood tests and the possible causes of the woman’s weight loss and fatigue.

The effect of different types of exercise on the heart rate of an athlete was investigated.

The athlete counted the number of beats in 10 seconds at the carotid artery pulse point, as shown in Figure 7.

This measurement was used to calculate the heart rate.

The athlete exercised for 20 minutes.

The heart rate was recorded every 5 minutes during each type of exercise.

State how the heart rate was calculated using this method.

Give two ways of improving the method used to obtain the data needed to calculate the heart rate.

Figure 8 shows the results of this investigation.

Comment on the difference in the heart rates during these types of exercise.

Exercise increases adrenalin levels.

State which endocrine gland secretes adrenalin.

Explain the effect of adrenalin on liver cells during exercise.

After high intensity exercise, the pH of muscles can decrease from pH 7.0 to pH 6.3.

Explain this change in pH.

Scientists use a technique called mark and recapture to estimate animal populations in a habitat.

A sample of the population is captured and a harmless mark is added to each animal.

These animals are released and after a period of time the population is sampled again.

This second sample includes some recaptured animals that have marks on them.

The population can be estimated using this equation

A scientist used this technique to determine the change in the population size of snails in a pond from March to July.

Figure 9 shows the results.

Using data from Figure 9, calculate the difference in the population size from March to July.

Difference in the population size_........

State two factors the scientist should control when sampling the habitat in March and July.

This pond is affected by eutrophication.

Explain one possible cause of eutrophication.

*(c) Reforestation has a beneficial effect on air composition and biodiversity.

Animal conservation projects can also have a beneficial effect on biodiversity.

Explain the beneficial effects of reforestation and animal conservation projects.