Edexcel GCSE Biology Paper 2 Higher November 2020 question paper 1BI0/2H

Figure 1 shows the sources of pollution and different levels of water pollution in a river.

Which part of the river will have the largest number of bloodworms?

Give the names of the two indicator species from the box which provide evidence for clean water.

Explain why sewage pollution in the river can decrease the oxygen levels in the water.

Excess fertilisers can cause a build‑up of nitrates in the rivers and lakes.

State the name given to a build‑up of nitrates in the lake.

State why the build‑up of nitrates is less likely to affect a river than a lake.

Figure 2 shows the leaves and flowers of water lily plants (Nymphaea odorata) on a lake.

Water lilies have stomata on the upper surface of the leaves.

Explain why water lilies have no stomata on the lower surface of the leaves.

The white petals of the water lily flowers cannot photosynthesise.

Which structure in leaf cells is the site of photosynthesis?

Glucose is made by photosynthesis.

Glucose is converted to another sugar to be transported in the plant.

What is the name of this sugar?

Describe how this sugar is transported from the leaves to the flowers of the water lily.

Figure 3 shows water lilies growing in a lake in Europe.

One water lily plant was brought from America 10 years ago and planted in the lake shown in Figure 3.

Explain why this non‑indigenous plant now covers the whole surface of the lake.

A slide of potato cells was viewed using a light microscope.

Figure 4 is a drawing of the slide showing starch grains in the potato cells.

Calculate the mean number of starch grains in potato cells P, Q and R.

Which structures are found in plant cells but are not found in animal cells?

A scientist investigated how the length of starch grains in potatoes changed when the potatoes were stored in the dark.

Figure 5 shows a potato after being stored in the dark.

Figure 5

Three potatoes were used in the investigation.

The length of starch grains in potato 1 were measured at the start.

The length of starch grains in potato 2 were measured after 5 weeks in the dark.

The length of starch grains in potato 3 were measured after 10 weeks in the dark.

Figure 6 shows the results.

Calculate the percentage difference in the mean length of starch grains in potato 2 at 5 weeks and in potato 3 at 10 weeks.

State two variables the scientist should have controlled to improve this investigation.

The starch grains in the potatoes became smaller as the starch was converted into glucose.

State why the potatoes need glucose.

Describe how starch is broken down into glucose.

Figure 7 shows the world human population from 1800 to 2015.

In 2015, 13% of the world human population were classified as malnourished.

Calculate, using Figure 7, how many people were classified as malnourished in 2015.

Protein is an important nutrient.

Describe the laboratory test for protein.

Figure 8 shows the mass of meat eaten in the world from 1980 to 2010.

Calculate the rate of increase in the mass of meat eaten in the world from 2000 to 2010.

_........ millions of tonnes per year

Figure 9 shows an energy pyramid.

Explain why the area labelled cattle is smaller than the area labelled plants.

The World Health Organisation uses this definition of food security.

Explain how a large increase in the mass of meat eaten will decrease food security in the future.

Trypsin is a protease enzyme used in the manufacture of food for babies.

Which food group is digested by trypsin?

The food is mashed before the trypsin is added.

Explain the advantage of mashing the food before adding the trypsin.

A manufacturer of baby food wanted to find out the optimum pH for trypsin.

Equal volumes of different pH solutions were placed in six separate test tubes.

5 cm³ of 1% trypsin solution was added to each test tube.

1.5 g of mashed food was placed in each test tube.

The time taken to digest the food was recorded.

State one other variable that should be controlled in this investigation.

State how this variable could be controlled.

The results are shown in Figure 10.

Describe the trends shown in this data.

At pH 4, the trypsin digested 1.5 g of mashed food at a rate of 0.8 g per minute.

Calculate the rate of digestion at pH 1.

Give your answer to one significant figure.

Explain the difference in the rate of reaction at pH 1 and the rate of reaction at pH 4.

Figure 11 shows the time taken for blood to clot at different temperatures.

Draw a graph to show the data in Figure 11.

Give two safety precautions that should be used when handling blood samples.

Which part of the blood causes blood to start clotting?

Give one advantage of a blood clot forming.

Explain how one structure of a vein helps the blood return to the heart.

A gardener decided to kill the dandelion plants growing in his lawn.

The gardener set up a trial to see which concentration of weed killer would kill the most dandelions and be most economical.

He counted the number of dandelion plants in six 1 m² areas of the lawn.

He made six different concentrations of weed killer solution.

He applied the solutions to each of the six different areas.

After two weeks, he counted the number of dandelion plants in each area.

The results are shown in Figure 12.

Give one variable the gardener should control when completing this trial.

State and explain the conclusions the gardener can make based on his trial.

Some weed killers contain plant hormones.

Explain how plant hormones work as weed killers.

Explain how phototropism is controlled in plant shoots.

Figure 13 shows the heart rate of person A and person B.

Person A does not do any regular exercise.

Person B has been running regularly for one year.

Both people rested for the first 6 minutes, then did the same high intensity exercise for the next 12 minutes, then rested.

Compare the heart rates of person A with the heart rates of person B.

The stroke volume for person B before exercising was 61 ml per beat.

Calculate the cardiac output for person B before exercising.

Give your answer in litres per minute.

_........ litres per minute

The cardiac output for person A during exercise was 5.5 litres per minute.

Explain why the heart rate for person A needed to be higher than the heart rate for person B during exercise.

Hyperthyroidism is caused by an overactive thyroid gland.

Figure 14 shows a person with a normal thyroid gland and a person with hyperthyroidism.

State one effect of hyperthyroidism on the thyroid gland.

The thyroid gland is part of the

Explain how negative feedback, involving the thyroid gland, controls metabolic rate.

(4).

*(c) Explain how hormones control the menstrual cycle.

A person with kidney disease may need kidney dialysis treatment.

Figure 15 shows an experiment to show how a dialysis membrane works.

Describe the method that would be used to find out what is present in the solution in the beaker, after one hour.

Explain how this experiment represents a simple model of kidney dialysis treatment.

*(b) The nephrons in the kidney remove unwanted substances from the blood.

Figure 16 shows the structure of a nephron.

Explain how substances are exchanged between the blood entering the nephron and the filtrate leaving the collecting duct.

Include reference to named structures of the nephron in your answer.