AQA GCSE Trilogy Biology Paper 1 Higher June 2018 question paper 8464/B/1H

This question is about cell structures.

Draw one line from each cell structure to the type of cell where the structure is found. Type of cell where the Cell Structure structure is found

Figure 1 shows a plant cell.

What are the names of structures A, B and C ? Tick one box.

A student observed slides of onion cells using a microscope. Figure 2 shows two of the slides the student observed.

The cells on the slides are not clear to see.

Describe how the student should adjust the microscope to see the cells on Slide A more clearly.

Describe how the student should adjust the microscope to see the cells on Slide B more clearly.

The student made the necessary adjustments to get a clear image. Figure 3 shows the student’s drawing of one of the cells.

The real length of the cell was 280 micrometres (µm). Calculate the magnification of the drawing.

Coronary heart disease (CHD) is a non-communicable disease. CHD is caused when fatty material builds up in the coronary arteries.

Explain what a non-communicable disease is.

Figure 4 shows a coronary artery of someone with CHD.

Explain how CHD can cause a heart attack.

Explain how lifestyle and medical risk factors increase the chance of developing CHD.

This question is about photosynthesis.

What is the correct balanced equation for photosynthesis? Tick one box.

What type of reaction is photosynthesis? Tick one box.

A student investigated the effect of light intensity on the rate of photosynthesis. Figure 5 shows the apparatus used.

Sodium hydrogencarbonate solution releases carbon dioxide gas for the pondweed. This is the method used.

1. Place the pondweed at 5 cm from the light source.

2. Measure the rate of photosynthesis by counting the number of bubbles produced in 1 minute.

3. Repeat with the pondweed at 10 cm and at 20 cm from the light source.

Counting the number of bubbles produced in 1 minute is not an accurate way to measure the rate of photosynthesis. Suggest two ways the method could be improved to measure the rate of photosynthesis more accurately.

The LED light source does not get hot. Explain why it is important that the pondweed remains at a constant temperature.

Light intensity can be calculated using the inverse square law:

Where I is light intensity and d is the distance of the pondweed from the light source. The student placed the pondweed at 5, 10 and 20 cm from the light source. Explain how light intensity changes as the distance of the pondweed from the light source is doubled. You must include calculations in your answer.

The student’s results are shown in Table 1

Predict how many bubbles of gas would be produced in 1 minute if the pondweed was placed 40 cm from the light source. Give a reason for your prediction.

Describe how the student could change the method to investigate the effect of carbon dioxide concentration on the rate of photosynthesis. You should include:

• how to change the independent variable

• two control variables.

Use Figure 5 on page 9 to help you answer this question.

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

1. Weigh five pieces of carrot.

2. Place each piece into a different tube.

3. Into each tube add 20 cm³ of water or one of the sugar solutions as shown in

Figure 6

4. Leave the apparatus for 2 hours.

5. Remove the carrot and dry each piece on paper towel.

6. Reweigh each piece.

7. Calculate the percentage (%) change in mass of each piece.

Figure 6 shows how the investigation was set up.

Table 2 shows the results.

Suggest why the student calculated the percentage (%) change in mass of each piece of carrot.

Complete Figure 7 using the results in Table 2

• Choose a suitable scale and label for the y-axis.

• Plot the results.

• Draw a line of best fit.

Estimate the concentration of sugar solution inside the carrot cells. Use your completed graph on Figure 7

Explain why the mass of the carrot in the 0.6 mol/dm³ sugar solution changed.

The student repeated the investigation using boiled pieces of carrot. The pieces of carrot did not change in mass. Suggest why.

Measles is a serious disease. A person can die from measles. Table 3 shows the number of medically confirmed cases of measles in England and Wales between 2012 and 2015

Suggest one reason why the actual number of cases of measles in England and Wales might be higher than is shown in Table 3

Calculate the percentage decrease in the number of medically confirmed cases of measles between 2012 and 2015

One reason for the decrease in the number of cases of measles is that more children were vaccinated against the disease. Vaccinating a large proportion of the population reduces the spread of the measles virus. Explain why.

Figure 8 shows the concentration of measles antibodies in the blood of a boy.

Explain the differences between antibody production after the vaccine injection and after exposure to the measles virus. You should include data from Figure 8

This question is about stem cells.

Give one place in a plant where stem cells are found.

What is one economic use of plant stem cells? Tick one box.

Embryonic stem cells divide by mitosis. Figure 9 represents a cell cycle for a human embryonic stem cell.

The mass of DNA in the cell at the start of the cycle is 6 picograms.

Convert 6 picograms to grams. Give your answer in standard form.

The time taken for this complete cell cycle is 15 hours. Calculate how many hours the cell spent in mitosis. Give your answer to 3 significant figures.

Describe what happens in each of the three stages of the cell cycle.

Figure 10 shows how embryonic stem cells are produced in therapeutic cloning for use in patients.

Give two advantages and two disadvantages of therapeutic cloning in medical treatments. Use Figure 10 to help you.

Disadvantage 2