AQA GCSE Trilogy Biology Paper 1 Higher June 2025 question paper 8464/B/1H

The heart is an organ that pumps blood around the body.

Figure 1 is a model of the heart and shows the direction of blood flow.

Draw one line from each blood vessel shown in Figure 1 to the name of the blood vessel.

Heart rate is controlled by a group of cells.

The group of cells acts as a pacemaker.

Where would the pacemaker be located in Figure 1 ?

Tick () one box.

Heart muscle cells contain many mitochondria.

Explain why heart muscle cells contain many mitochondria.

A small number of people are born with a ‘hole in the heart’.

Figure 2 shows the position of a hole in the heart.

The hole allows some blood from the right side of the heart to mix with blood in the left side of the heart.

Suggest two symptoms of having a hole in the heart.

In an operation to repair a hole in the heart:

• a flexible tube is inserted into a blood vessel and guided to the heart

• a mesh patch is passed down the tube

• the mesh patch covers the hole.

Heart tissue grows around the mesh and closes the hole.

Suggest two possible risks of this operation to repair a hole in the heart.

Chickenpox is an infectious disease that affects young children.

One symptom of chickenpox is small blisters on the skin.

Suggest one way chickenpox spreads from an infected person to other people.

Chickenpox is caused by a type of pathogen that cannot be treated with antibiotics.

Give the reason why chickenpox cannot be treated with antibiotics.

A vaccine that could be used to protect against chickenpox has been produced.

What does a vaccine contain that causes a person to become immune to a disease?

Give three reasons why a new vaccine must be tested.

Explain how a vaccine for chickenpox gives immunity against the disease.

You should refer to how the body responds to:

• the vaccine

• chickenpox pathogens that enter the body after vaccination.

Photosynthesis is important for plant growth.

A student used pondweed to investigate the rate of photosynthesis.

Figure 3 shows the apparatus used.

This is the method used.

1. Set up the apparatus as shown in Figure 3.

2. Switch on the lamp.

3. After 2 hours, record the volume of oxygen collected in the measuring cylinder.

4. Repeat steps 1 to 3 a further five times, increasing the distance between the lamp

and the pondweed each time.

5. Calculate the rate of oxygen production for each distance.

Figure 4 shows the results.

Which measuring cylinder should the student have used to give the most accurate results?

Tick () one box.

Light intensity can be calculated using the inverse square law.

The equation shows the inverse square law.

Explain how light intensity changed as the distance of the pondweed from the light source was doubled.

Include calculations in your answer.

Use data from Figure 4.

The student did the investigation at 10 °C.

The student repeated the investigation at 20 °C and again at 80 °C.

Explain how repeating the investigation at 20 °C would affect the results.

Explain how repeating the investigation at 80 °C would affect the results.

A student investigated the effect of surface area on the mass of potato pieces placed in water.

This is the method used.

1. Cut 5 cylinders from one potato. Cut each cylinder to a length of 3 cm.

2. Cut 4 of the cylinders into different numbers of pieces.

3. Dry each piece of potato on a paper towel.

4. Record the mass of each group of potato pieces.

5. Put each group of potato pieces into different beakers containing distilled water as

shown in Figure 5.

6. After 30 minutes remove and dry each group of potato pieces.

7. Record the mass of each group of potato pieces.

8. Calculate the percentage increase in mass for each group of potato pieces.

Table 1 shows the results.

Why is it more valid to calculate the percentage increase in mass rather than using the increase in mass?

Describe the relationship between total surface area and percentage increase in mass.

Use Table 1.

Explain why the potato pieces increased in mass.

The student repeated the investigation.

The potato pieces were in the beakers of distilled water for 24 hours.

Explain what results would be expected after leaving the investigation set up for 24 hours.

The method used is repeated below.

1. Cut 5 cylinders from one potato. Cut each cylinder to a length of 3 cm.

2. Cut 4 of the cylinders into different numbers of pieces.

3. Dry each piece of potato on a paper towel.

4. Record the mass of each group of potato pieces.

5. Put each group of potato pieces into different beakers containing distilled water as

shown in Figure 5 on page 13.

6. After 30 minutes, remove and dry each group of potato pieces.

7. Record the mass of each group of potato pieces.

8. Calculate the percentage increase in mass for each group of potato pieces.

A different student wanted to investigate the effect of salt concentration on potato tissue.

Describe how the student could change the method to investigate the effect of salt concentration on potato tissue.

This question is about plants.

Some plants can respire anaerobically.

Which are the two products of anaerobic respiration in plants?

Tick () two boxes.

Figure 6 shows the structure of part of a leaf

What is the name of tissue A ?

Explain how tissue A is adapted to its function.

Plants absorb water from the soil.

Describe how water is transported from the soil through plant tissues to the atmosphere.

Ciliated cells have small hair-like structures called cilia on the cell surface.

Ciliated cells are found in the trachea and in the oviducts.

Oviducts are part of the female reproductive system.

Figure 7 shows cilia lining an oviduct.

Give one piece of evidence that an electron microscope was used to produce the image shown in Figure 7.

Do not refer to colour in your answer.

Describe the function of ciliated cells in the oviduct.

The mean length of the cilia in an image was 6 mm.

The cilia were viewed at a magnification of 1.5 × 10³

Calculate the real mean length of the cilia.

Give your answer in micrometres (µm).

Red blood cells are a type of cell found in humans.

People with anaemia do not have enough red blood cells.

Explain why a person with anaemia is likely to experience muscle fatigue.

Scientists have produced red blood cells from stem cells in a laboratory.

The scientists:

• collected a sample of blood from a donor

• extracted 5 × 10⁵ stem cells from the sample.

Each stem cell was developed into 100 000 red blood cells.

35% of the red blood cells made from stem cells are suitable to use in a patient.

Calculate the number of red blood cells made from the donor’s sample that could be used in a patient.

Give your answer in standard form.

Patients with anaemia are sometimes given a blood transfusion.

A blood transfusion is when a patient is given blood.

The patient can be given red blood cells:

• produced from stem cells in a laboratory or

• from a whole blood donation.

Table 2 gives information about the two sources of red blood cells.

Evaluate the use of red blood cells:

• produced from stem cells in a laboratory

• from a whole blood donation.

You should refer to costs in your answer.