AQA GCSE Trilogy Biology Paper 1 Higher November 2020 question paper 8464/B/1H

A student investigated the effect of different concentrations of sugar solution on pieces of potato. This is the method used.

1. Cut five pieces of potato.

2. Record the starting mass of each piece of potato.

3. Place each piece of potato in a different concentration of sugar solution.

4. After 24 hours remove the pieces of potato from the solutions.

5. Record the final mass of each piece of potato.

6. Calculate the change in mass for each piece of potato.

What is the independent variable? Tick (✓) one box.

Table 1 shows the results.

Explain why the potato in 0.0 mol/dm³ sugar solution increased in mass.

Complete Figure 1. Some of the results have been plotted for you. You should:

• plot the data from Table 1

• draw a line of best fit through all the points.

The mass of a piece of potato does not change when: concentration of solution inside cells = concentration of solution outside cells

Determine the concentration of sugar solution inside the potato cells. Use Figure 1.

Table 1 is repeated below.

Calculate the percentage change in mass for the potato in 0.2 mol/dm³ sugar solution. Use Table 1. Use the equation:

Give your answer to 3 significant figures.

Starch is digested to form sugar molecules in the digestive system.

What is the name of the enzyme that digests starch?

Where are most food molecules absorbed? Tick (✓) one box.

Figure 2 shows two villi. Figure 2 also shows one cell on the surface of a villus as seen using an electron microscope.

Give one advantage of using an electron microscope compared with using a light microscope.

What type of blood vessel is labelled X ? Tick (✓) one box.

The real length of one villus is 0.8 mm Calculate the image length if the villus is viewed at a magnification of ×20 Use the equation:

Figure 3 shows two cells from the surface of a villus. There are sugar molecules inside and next to each cell.

Name the process by which sugar moves into cell A.

Name the process by which sugar moves into cell B.

Give one use of sugar in the body.

Figure 2 is repeated below.

Explain how villi are adapted for efficient absorption of sugar molecules.

Being overweight can affect the health and life expectancy of a person.

Give one disease related to being overweight.

Body mass index (BMI) helps to show if a person has a healthy body mass for their height. BMI is calculated using the equation:

A woman has a BMI of 27 and a body mass of 68.1 kg Calculate the woman’s height in metres.

Figure 4 shows a height-body mass chart for adults.

Which weight category describes the woman in Question 03.2 ? Tick (✓) one box.

People are encouraged to control their body mass with diet and exercise. Describe how the balance between the mass of food eaten and the amount of exercise a person does controls body mass.

During long periods of vigorous exercise the body respires anaerobically. Explain the changes that happen in the body during and after vigorous exercise.

Cells are the basic units of all forms of life.

Describe four differences between a bacterial cell and a plant cell.

Gonorrhoea is a bacterial disease. A new vaccine is being developed against gonorrhoea. Describe how a vaccine would work to prevent gonorrhoea.

Another disease caused by bacteria is salmonella food poisoning. In the UK, chickens are vaccinated against Salmonella bacteria to reduce the number of cases of food poisoning in humans.

Explain how vaccinating chickens reduces the number of cases of salmonella food poisoning.

Give one way that the spread of salmonella food poisoning from one human to another is controlled. Do not refer to vaccination in your answer.

The number of cases of salmonella food poisoning is usually higher in summer than in winter. Suggest one reason why.

This question is about photosynthesis and food production.

How can oxygen production be used to show the rate of photosynthesis?

Scientists investigated factors affecting the rate of photosynthesis in tomato plants. The tomato plants were growing in a commercial greenhouse in the UK during winter. Figure 5 shows the results.

The percentage of carbon dioxide in the Earth’s atmosphere is 0.04%

Name the factor that is limiting the rate of photosynthesis at point X.

Farmers growing tomatoes commercially try to control the rate of photosynthesis and

make maximum profit. A farmer can control the temperature and carbon dioxide concentration in a greenhouse.

What is the minimum light intensity a farmer should use to get the maximum rate of photosynthesis shown in Figure 5 ?

The light intensity you gave in Question 05.3 may not give the farmer maximum profit. Explain why.

Explain the results when the light intensity was 0 lux. Use Figure 5.

New drugs are tested and trialled before they can be licensed to treat patients. Figure 6 shows how much time the different stages of testing took for one new drug.

How much more time did the clinical trials take compared with the preclinical testing? Tick (✓) one box.

During Phase 1 clinical trials low doses of the drug are tested on healthy volunteers.

Suggest one reason why low doses of the drug are used in Phase 1 clinical trials.

Suggest two reasons why healthy volunteers are used in Phase 1 clinical trials.

The results of clinical trials can only be published after peer review by other scientists. Suggest one reason why the results must be reviewed by other scientists.

A drug is only licensed for the medical conditions it was tested to treat in the clinical trials. Drug regulations:

• control what drugs a doctor can prescribe

• ensure doctors can prescribe a drug with confidence

• protect patients.

AMD is an eye condition that can result in very poor vision. Doctors treat approximately 40 000 new cases of AMD each year. Two drugs licensed to treat AMD in the UK are drug A and drug B. In many other countries drug C is used to treat AMD. Drug C is only licensed in the UK to treat cancer. The cost per injection for each drug is:

• drug A £561

• drug B £800

• drug C £28

The number of injections required to treat AMD is the same for each drug.

In 2018 the High Court in the UK gave permission for drug C to be used to treat AMD. Evaluate the decision to allow the use of drug C to treat AMD in the UK.