AQA GCSE Biology Paper 1 Higher June 2018 question paper 8461/1H

Eating food containing Salmonella bacteria can cause illness.

Two symptoms of infection by Salmonella are vomiting and diarrhoea.

What causes these symptoms?

Give two ways a person with a mild infection of Salmonella can help prevent the spread of the bacteria to other people.

In very serious infections of Salmonella, a doctor can prescribe drugs to kill the bacteria.

What type of drug can the doctor prescribe to kill the bacteria?

A person with AIDS may take longer than a healthy person to recover from a Salmonella infection.

Explain why.

Salmonella bacteria can be transmitted from chickens to humans. Chickens can be vaccinated to prevent the transmission of Salmonella bacteria to humans.

Suggest one other way farmers could prevent the transmission of Salmonella from chickens to humans.

A restaurant owner employed a scientist to test the effectiveness of two kitchen cleaning liquids.

The scientist took samples from two work surfaces:

before the surfaces had been cleaned with the cleaning liquids

• after the surfaces had been cleaned with the cleaning liquids.

The samples were then analysed for the number of bacteria they contained.

The results are shown in Figure 1.

Which cleaning liquid is the more effective?

Give a reason for your answer.

The scientist investigated the effect of cleaning liquid A and cleaning liquid B on Salmonella bacteria grown in a laboratory.

Figure 2 shows the way the investigation was set up.

The Petri dish was placed in an incubator at 25 °C for 48 hours.

After 48 hours, the scientist calculated the area around each paper disc where no bacteria were growing.

The results are shown in Table 1.

What measurement would the scientist need to take to calculate the area where no bacteria were growing?

Give one change to the investigation that would allow the scientist to check if the results are repeatable.

The scientist showed the results to the restaurant owner.

Both cleaning liquids cost the same per dm³.

Suggest one other factor the restaurant owner should consider when choosing which cleaning liquid to use.

Metabolism is the sum of all the chemical reactions in the cells of the body.

One metabolic reaction is the formation of lipids.

Give one other metabolic reaction in cells.

Table 2 shows the mean metabolic rate of humans of different ages.

What two conclusions can be made from the data in Table 2 ?

Tick two boxes.

Calculate the percentage decrease in the mean metabolic rate of males between 5 years and 45 years of age.

Use the equation:

Give your answer to 3 significant figures.

Regular exercise can increase metabolic rate.

Two people did five minutes of gentle exercise from rest.

Table 3 shows the effect of the exercise on their heart rates.

Describe two differences in the response of person R and person S to the exercise.

Use information from Table 3.

Complete the line graph in Figure 3 for person S.

You should:

• add the scale to the x axis

• label the x axis.

After five minutes of exercise, the heart rate of person S was 132 beats per minute. When person S rested, his heart rate decreased steadily at a rate of 12 beats every minute.

Calculate how much time it would take the heart rate of person S to return to its resting rate.

A student made the following hypothesis about the heart rate of smokers and non-smokers during exercise.

“During exercise, the heart rate of smokers increases more than the heart rate of non-smokers.”

Design an investigation that would allow you to test this hypothesis.

The circulatory system is composed of the blood, blood vessels and the heart.

Urea is transported in the blood plasma.

Name two other substances transported in the blood plasma.

Some athletes train at high altitude.

Training at high altitude increases the number of red blood cells per cm³ of blood.

Explain why having more red blood cells per cm³ of blood is an advantage to an athlete.

Which two blood vessels carry deoxygenated blood?

Tick two boxes.

Figure 4 shows the three types of blood vessel.

Which type of blood vessel carries blood into the right atrium?

Tick one box.

Compare the structure of an artery with the structure of a vein.

Heart rate is controlled by a group of cells. This group of cells act as a pacemaker.

Figure 5 shows a section through the heart.

Draw an X on Figure 5 to show the position of the pacemaker.

A patient may be fitted with an artificial pacemaker.

What condition may be treated using an artificial pacemaker?

A student carried out an investigation using chicken eggs.

This is the method used.

1. Place 5 eggs in acid for 24 hours to dissolve the egg shell.

2. Measure and record the mass of each egg.

3. Place each egg into a separate beaker containing 200 cm³ of distilled water.

4. After 20 minutes, remove the eggs from the beakers and dry them gently with a paper towel.

5. Measure and record the mass of each egg.

Table 4 shows the results.

Another student suggested that the result for egg 4 was anomalous.

Do you agree with the student?

Give a reason for your answer.

Calculate the percentage change in mass of egg 3.

Explain why the masses of the eggs increased.

Explain how the student could modify the investigation to determine the concentration of the solution inside each egg.

Chicken egg shells contain calcium. Calcium ions are moved from the shell into the cytoplasm of the egg.

Table 5 shows information about the concentration of calcium ions.

Explain how calcium ions are moved from the shell into the cytoplasm of the egg.

Plants can be infected by fungi, viruses and insects.

Aphids are small insects that carry pathogens.

Figure 6 shows an aphid feeding from a plant stem.

An aphid feeds by inserting its sharp mouthpiece into the stem of a plant.

Give the reason why the mouthpiece of an aphid contains a high concentration of dissolved sugars after feeding.

Plants infected with aphids may show symptoms of magnesium deficiency.

Magnesium deficiency symptoms include:

• yellow leaves

• stunted growth.

Explain how a deficiency of magnesium could cause these symptoms.

A farmer thinks a potato crop is infected with potato virus Y (PVY).

The farmer obtains a monoclonal antibody test kit for PVY.

To make the monoclonal antibodies a scientist first isolates the PVY protein from the virus.

Describe how the scientist would use the protein to produce the PVY monoclonal antibody.

Table 8 shows information about some food components in cow’s milk.

How much more milk would a typical adult have to drink to get their RDA for calcium compared with the amount of milk needed to get their RDA for vitamin B-12?

Describe how a student could test cow’s milk to show whether it contains protein and different types of carbohydrate.

A scientist investigated the effect of bile on the breakdown of fat in a sample of milk.

The scientist used an indicator that is colourless in solutions with a pH lower than 10, and pink in solutions with a pH above 10.

This is the method used.

1. Add 1 drop of bile to a test tube and one drop of water to a second test tube.

2. Add the following to each test tube:

• 5 cm³ of milk

• 7 cm³ of sodium carbonate solution (to make the solution above pH 10)

• 5 drops of the indicator

• 1 cm³ of lipase.

3. Time how long it takes for the indicator in the solutions to become colourless.

The results are shown in Table 9.

Explain why the indicator in both tubes became colourless.

Give the reason why the measurement of the time taken for the indicator to become colourless might be inaccurate.

Explain the difference in the results for the two test tubes in Table 9.