Photosynthesis

A student investigated the effect of different factors on photosynthesis.

The student used three leaves growing on the same plant.

Each leaf was treated in a different way.

After 48 hours the student tested each leaf for starch.

Table 3 shows the results.

Explain the results for the three leaves.

In another investigation the student used a different type of plant.

The plant was left uncovered in the light for 48 hours.

After 48 hours the student tested a leaf from the plant for starch.

Figure 6 shows the leaf before it was tested for starch.

Complete Table 4 to show the results you would expect for the starch test on the leaf in Figure 6.

Explain the results you gave in Question 07.2.

In some leaves, the green parts become yellow because of an ion deficiency.

Which ion is deficient in a plant with yellow leaves?

Give the scientific term that describes the yellow colour of the leaves.

The rate of photosynthesis is affected by different factors.

How could the oxygen produced during photosynthesis be used to measure the rate of photosynthesis?

Light, carbon dioxide and temperature are limiting factors of photosynthesis.

Figure 7 shows how the rate of photosynthesis is affected by light, carbon dioxide and temperature.

At point A on Figure 7, light is a limiting factor.

What is meant by a ‘limiting factor’?

Explain the effect of increasing temperature and increasing carbon dioxide concentration on the rate of photosynthesis shown in Figure 7.

Photosynthesis investigations often use a light source.

The spreading out of light from a source obeys the inverse square law.

The inverse square law links light intensity to distance from the light source.

Which of the following shows the inverse square law?

Tick (✓) one box.

Photosynthesis produces oxygen.

Complete the word equation for photosynthesis.

Choose answers from the box.

_____________________ + _____________________ → _____________________ + oxygen

Explain how oxygen is used in cells.

A student investigated the effect of light from different coloured light bulbs on photosynthesis.

The student:

• used pondweed in a beaker of water

• used different coloured light bulbs in a lamp

• counted the number of bubbles of oxygen the pondweed produced in 2 minutes for each colour of light bulb.

Give one hazard the student would need to consider when using the apparatus in this investigation.

Give the risk the hazard would cause.

The student needed to keep the temperature of the water in the beaker the same throughout the investigation.

Describe how the student could keep the temperature of the water the same.

The beaker of water contained the pondweed.

Explain why the temperature of the water in the beaker needed to be kept the same throughout the investigation.

Table 3 shows the results.

Which colour of light caused the highest rate of photosynthesis in the pondweed?

Tick (✓) one box.

What is the best way to display the data in Table 3 ?

Tick (✓) one box.

The student wanted to measure the volume of oxygen the pondweed produced in 2 minutes.

Name one piece of apparatus the student could use to measure the volume of oxygen.

Another student investigated the effect of light intensity on the rate of photosynthesis.

Figure 1 shows the results.

Describe what Figure 1 shows about the relationship between light intensity and the rate of photosynthesis.

This question is about photosynthesis.

Complete the symbol equation for photosynthesis.

Figure 8 shows how the rate of photosynthesis changes with light intensity.

Which part of the graph could be represented by the equation y = mx + c ? Tick (✓) one box.

A student investigated the effect of colour of light on the rate of photosynthesis

in leaves. Figure 9 shows how the investigation was set up.

Table 5 shows the results.

Give one way the student could change the colour of the light shining on the leaf discs.

Give the independent variable and the dependent variable in this investigation. Independent variable

Dependent variable

All of the air had to be removed from the leaf discs before placing them in the beaker. Suggest one reason why.

The leaf discs were placed in a beaker of sodium hydrogencarbonate

Explain why sodium hydrogencarbonate solution was used instead of water.

Explain why the leaf discs moved to the surface of the solution during the investigation.

There are two types of chlorophyll in leaves.

Figure 10 shows the percentage of different wavelengths of light that the two types of chlorophyll absorb.

Table 6 shows the colour of different wavelengths of light.

Suggest the advantage to a plant of having two types of chlorophyll.

Table 5 is repeated below.

The leaf discs in the investigation are green. Explain the results in Table 5 for blue light and for green light. Use data from Figure 10 and Table 6.

Plants take up water from the soil through their roots.

Some of the water is used for photosynthesis.

Complete the word equation for photosynthesis.

Choose answers from the box.

Water and dissolved substances are transported through a plant.

Complete the sentences.

Choose answers from the box.

Water moves from the roots to the leaves in the

Water is lost from leaves through pores called

Dissolved sugars are transported in the.

Table 3 shows the rate of transpiration in four different plant species.

Calculate how many times greater the rate of transpiration of species A is than the rate of transpiration of species B.

Give your answer to 2 significant figures.

Which factor could cause species A to have a higher rate of transpiration than species B ?

Tick (✓) one box.

Which environmental change would cause an increase in the rate of transpiration?

Tick (✓) one box.

Which plant species in Table 3 is most likely to live in a dry desert?

Tick (✓) one box.

Some plants have adaptations that help them survive.

Figure 6 shows part of a gorse plant.

How will the sharp spines help the gorse plant survive?

Animals also have adaptations to help them survive.

Figure 7 shows two insects.

Hornets are insects that sting other animals and cause pain.

Hornet moths do not sting other animals.

Explain why animals avoid eating the hornet moth.

A cactus is a plant that lives in a dry environment. Figure 6 shows part of a cactus plant.

Give one adaptation shown in Figure 6 that helps to prevent the cactus from being eaten by animals.

A plant may produce poisons that make animals unwell. What is this type of defence mechanism?

Tick (✓) one box.

Some desert plants only grow leaves after it has rained. As soon as the soil dries out, the leaves fall off. How could the leaves falling off the plant be an advantage to a plant that lives in a dry environment? Tick (✓) one box.

The stem of a cactus is green.

What causes the green colour in the stem?

What is the advantage to the cactus of having a green stem?

The stem of a cactus contains many different tissues.

What name is given to a group of tissues working together? Tick (✓) one box.

Name one substance transported through the xylem in the stem of the cactus.

Name the tissue that transports dissolved sugars through the stem of the cactus.

Figure 7 shows part of a deadly nightshade plant.

How will the poisonous berries help the deadly nightshade plant to survive?

Which type of defence mechanism are the berries? Tick (✓) one box.

Figure 8 shows part of a gorse plant.

Suggest how the gorse plant is adapted to defend itself.

The green leaves of the gorse plant make glucose for the plant to use. What are two uses of glucose in the gorse plant? Tick (✓) two boxes.

A student wanted to show that the leaves of a gorse plant contain glucose. The student crushed the leaves to extract the liquid from the cells. Describe the method the student could use to test the liquid from the cells for glucose. Include the result if glucose is present.

The roots of the gorse plant have bacteria that turn nitrogen gas into nitrate ions. Explain why nitrate ions are needed by the gorse plant.

The roots of gorse plants can be infected by honey fungus. The honey fungus produces tiny spores underground. Suggest how the honey fungus spores travel from the roots of an infected gorse plant to the roots of a healthy gorse plant.

A drug can be extracted from gorse seeds.

Doctors want to trial the drug from gorse seeds to see if it can treat diarrhoea.

Which two factors must the doctors test the drug for in the trial? Tick (✓) two boxes.

In the trial some patients will take tablets made from gorse seeds and some patients will take tablets made from sugar. What are the tablets made from sugar called? Tick (✓) one box.

This question is about photosynthesis.

Complete the word equation for photosynthesis.

Describe how energy for the photosynthesis reaction is gained by plants.

Students investigated the effect of temperature on the rate of photosynthesis. The students shone light from a lamp onto pondweed and measured the volume of oxygen produced per hour. Table 3 shows the results.

Calculate mean value X.

The students identified one anomalous result in Table 3.

Draw a ring around the anomalous result in Table 3.

Suggest one possible cause of the anomalous result.

How did the students deal with the anomalous result?

Give one factor the students should have kept constant in this investigation.

Table 3 is repeated below.

Why did the rate of photosynthesis decrease from 35 °C to 45 °C?

Complete Figure 10 using data from Table 3. You should:

• label the y-axis

• use a suitable scale for the y-axis

• plot the mean data from Table 3 for temperatures from 25 °C to 45 °C

• draw a line of best fit.

This question is about photosynthesis.

Complete the word equation for photosynthesis.

Describe how energy for the photosynthesis reaction is gained by plants.

Students investigated the effect of temperature on the rate of photosynthesis. The students shone light from a lamp onto pondweed and measured the volume of oxygen produced per hour. Table 1 shows the results.

Calculate mean value X.

The students identified one anomalous result in Table 1.

Draw a ring around the anomalous result in Table 1.

Suggest one possible cause of the anomalous result.

How did the students deal with the anomalous result?

Give one factor the students should have kept constant in this investigation.

Table 1 is repeated below.

Why did the rate of photosynthesis decrease from 35 °C to 45 °C?

Complete Figure 1 using data from Table 1. You should:

• label the y-axis

• use a suitable scale for the y-axis

• plot the mean data from Table 1 for temperatures from 25 °C to 45 °C

• draw a line of best fit.

Lipases break down lipids. Which two products are formed when lipids are broken down? Tick (✓) two boxes.

One model used to explain enzyme action is the ‘lock and key theory’.

Figure 7 shows a model of the theory.

Explain the ‘lock and key theory’ of enzyme action. Use information from Figure 7 in your answer.

There are many different types of lipase in the human body. Why does each different type of lipase act on only one specific type of lipid molecule?

Students investigated the presence of starch and glucose in the leaves of

geranium plants. This is the method used.

1. Place two identical geranium plants on a bench near a sunny window for two days.

2. After two days:

leave one plant near the window for two more days.

place one plant in a cupboard with no light for two more days.

3. Remove one leaf from each plant.

4. Crush each leaf to extract the liquid from the cells.

5. Test the liquid from each leaf for glucose and for starch.

Describe how the students would find out if the liquid from the leaf contained glucose.

Describe how the students would find out if the liquid from the leaf contained starch.

Table 2 shows the students’ results.

Explain why the leaf in the light for four days contained both glucose and starch.

Explain why the leaf left in a cupboard with no light for two days did contain glucose but did not contain starch.

Suggest one way the students could develop the investigation to find out more about glucose and starch production in plants.

This question is about photosynthesis.

Complete the word equation for photosynthesis:

A student investigated photosynthesis using pondweed.

Figure 14 shows the apparatus the student used.

This is the method used.

1. Set up the apparatus as shown in Figure 14.

2. Switch on the lamp.

3. After 20 minutes, record the volume of oxygen collected in the measuring cylinder.

4. Repeat steps 1–3 using bulbs of different power output.

What was the independent variable in the investigation?

Tick (✓) one box.

Suggest two ways the method could be improved so the results would be more valid.

Table 9 shows the student’s results.

Calculate value X in Table 9.

Complete Figure 15.

You should:

• label the x-axis

• use a suitable scale

• plot the data from Table 9 and your answer to Question 09.4

• draw a line of best fit.

Determine the expected rate of photosynthesis with a bulb of power output 75 watts.

Use Figure 15.

Which graph shows the effect of temperature on the rate of photosynthesis?

Tick (✓) one box.

This question is about photosynthesis.

Complete the word equation for photosynthesis:

A student investigated photosynthesis using pondweed.

Figure 3 shows the apparatus the student used.

This is the method used.

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

2. Switch on the lamp.

3. After 20 minutes, record the volume of oxygen collected in the measuring cylinder.

4. Repeat steps 1–3 using bulbs of different power output.

What was the independent variable in the investigation?

Tick (✓) one box.

Suggest two ways the method could be improved so the results would be more valid.

Table 3 shows the student’s results.

Calculate value X in Table 3.

Complete Figure 4.

You should:

• label the x-axis

• use a suitable scale

• plot the data from Table 3 and your answer to Question 03.4

• draw a line of best fit.

Determine the expected rate of photosynthesis with a bulb of power output 75 watts.

Use Figure 4.

Which graph shows the effect of temperature on the rate of photosynthesis?

Tick (✓) one box.