AQA GCSE Trilogy Biology Paper 1 Higher November 2021 question paper 8464/B/1H

Plants absorb light for photosynthesis.

Which is the equation for photosynthesis? Tick (✓) one box.

A student investigated the effect of light intensity on the rate of photosynthesis. Figure 1 shows the apparatus.

This is the method used.

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

2. Place the pondweed 10 cm away from the lamp.

3. Switch on the lamp.

4. Record the number of bubbles of gas produced in 5 minutes.

5. Repeat steps 2 to 4 with the pondweed at different distances from the lamp.

What was the independent variable in this investigation? Tick (✓) one box.

The lamp gets warm when it is on. This causes the temperature of the water

to increase.

Explain how an increase in temperature would affect the results of this investigation.

Suggest one way the investigation could be improved so the temperature of the water does not increase.

Suggest two improvements to the investigation so the results would be more valid. Do not refer to controlling the temperature of the water.

Table 1 shows the results.

Calculate the rate of photosynthesis when the pondweed was 40 cm from the lamp. Give the rate of photosynthesis as the number of bubbles of gas produced per minute.

Give one conclusion that can be made from Table 1.

Plot the data from Table 1 on Figure 2. Draw a line of best fit.

Predict the number of bubbles that would be produced in 5 minutes if the pondweed was 60 cm from the lamp. Use Figure 2.

Describe how to test a sample of food for protein, starch and sugar. Give the colours that would be seen if the food sample contained protein, starch and sugar.

Fermentation in yeast is used in the manufacture of bread and alcoholic drinks. The equation for fermentation is: glucose → ethanol + carbon dioxide

Fermentation is an exothermic reaction. What does exothermic mean?

A student investigated the effect of temperature on fermentation in yeast. Figure 3 shows the apparatus.

This is the method used.

1. Mix yeast with sugar solution in a flask.

2. Pour a layer of oil over the surface of the mixture.

3. Put the flask in a water bath at 2 °C and leave for 20 minutes.

4. Attach a gas syringe.

5. Record the volume of gas collected every 5 minutes for 30 minutes.

6. After 30 minutes move the flask to a water bath at 35 °C.

7. Continue to record the volume of gas collected every 5 minutes.

Suggest why a layer of oil was needed on the surface of the mixture.

Suggest why the mixture was left for 20 minutes before the gas syringe was attached.

Steps 1 to 4 of the method were repeated at 35 °C.

The volume of gas collected was recorded every 5 minutes for 45 minutes. Table 2 shows the results for both flasks for the first 30 minutes. Table 3 shows the results for the last 15 minutes, when both flasks were at 35 °C.

Explain the results from 0 minutes to 45 minutes for the flask that was at 2 °C and was then moved to 35 °C. Use Table 2 and Table 3.

Explain the results from 0 minutes to 45 minutes for the flask kept at 35 °C. Use Table 2 and Table 3.

Pathogens are microorganisms that cause diseases. Gonorrhoea, malaria and measles are three diseases in humans.

Draw one line from each disease to the pathogen that causes the disease.

Malaria is transmitted by mosquitos. Male mosquitos can be sterilised so they are infertile. The spread of malaria is reduced by releasing sterile mosquitos into the environment. Explain how releasing sterile mosquitos reduces the spread of malaria.

Pathogens also cause diseases in plants. Figure 4 shows a rose black spot fungal spore and a tobacco mosaic virus.

Name the piece of equipment used to view the virus.

How many times longer is the fungal spore than the virus? Use Figure 4.

Explain why plants infected with tobacco mosaic virus grow slowly.

Figure 5 shows the human heart.

Which blood vessel transports blood with the highest oxygen concentration into the heart? Tick (✓) one box.

Blood pressure is a measure of the force of the blood against the walls of the blood vessels. Which blood vessel transports blood at the highest pressure? Tick (✓) one box.

What is the correct order for blood flowing through the heart to the lungs? Tick (✓) one box.

Every year thousands of people in the UK have heart attacks.

A heart attack is caused when the heart muscle cells do not get enough oxygen, causing the cells to die.

Statins and stents are two treatments used to reduce the risk of someone having a heart attack. Evaluate the use of statins compared with the use of a stent to reduce the risk of a heart attack.

Many people who survive a heart attack get out of breath easily when they exercise gently. Explain why heart attack survivors get out of breath easily.

Scientists have developed patches of beating heart cells to repair damaged

heart tissue. The patches are placed onto areas of the heart where cells have died. New cells grow to replace the dead cells. The patches are made using a person’s own cells that are converted into stem cells.

Explain why stem cells are used to make the patches.

The scientists could have used human embryonic stem cells to make the patches. Give two advantages of using stem cells made from the person’s own cells, rather than using embryonic stem cells.

This question is about plant transport systems.

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

Dissolved sugars are moved through a plant in phloem tissue. What is the name of the process that moves dissolved sugars through phloem tissue?

Phloem tissue is made of sieve tube cells and companion cells. Figure 6 shows a section of phloem tissue.

Explain one way sieve tube cells are specialised for their function. Use Figure 6.

What does the structure of the companion cells suggest about the process that moves dissolved sugars through the phloem tissue? Give a reason for your answer. Use Figure 6.

Describe why it is important that dissolved sugars are moved both upwards and downwards in a plant.