OCR Gateway GCSE Biology

Topic Questions

1.4 Photosynthesis

1
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1 mark

An experiment is set up with four test tubes as shown in the diagram below. All four test tubes are left in sunlight for 6 hours.

1-2

Which test tube would contain the least amount of dissolved carbon dioxide after 6 hours?

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2
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Which statement correctly describes why plants are called primary producers?

  • They release oxygen into the atmosphere

  • They use chemical energy from the sun to produce glucose

  • They release heat energy during photosynthesis

  • Energy stored in the biomass of plants makes its way through the food chain

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3
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The process of photosynthesis happens in two main stages.

Which row accurately describes each stage?

  Stage 1 Stage 2
A

Energy from light splits water into oxygen gas and hydrogen ions

Carbon dioxide combines with hydrogen ions to make glucose

B

Carbon dioxide combines with water

Glucose is made and oxygen released

C

Carbon dioxide is taken into the leaf through stomata

Energy from light is used to combine carbon dioxide with hydrogen

D

Energy from light splits carbon dioxide into carbon and oxygen atoms

Water combines with the carbon and oxygen atoms to make glucose

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4
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The following experimental set-up is used to measure the rate of oxygen production of an aquatic plant from photosynthesis.

The experiment was repeated several times and the mean volume of oxygen collected was determined. 

insert-diagram_-6-q9-experiment

Which two factors should be kept constant during the experiment?

  • The size of the funnel and temperature of the water.

  • The size of the aquatic plant and the amount of water in the beaker.

  • The size of the aquatic plant and the amount of gas in the measuring cylinder.

  • The distance from the light source and size of the aquatic plant.

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5
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The diagram below shows the results of three experiments to measure the rate of photosynthesis under different conditions.

Experiment 1 measured the effect of light intensity on photosynthesis

Experiment 2 measured the effect of temperature on photosynthesis

Experiment 3 measured the effect of carbon dioxide on photosynthesis

6-q5-limiting-factors

Which of the following correctly identifies the limiting factor for photosynthesis in each experiment?

  1 2 3
A light intensity light intensity carbon dioxide concentration
B temperature temperature light intensity
C light intensity temperature carbon dioxide concentration
D light intensity carbon dioxide concentration temperature

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6
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Higher Tier Only

The graph shows the effect of carbon dioxide concentration on the rate of photosynthesis.q5-paper1h-spec2018-ocrgcsebio
Where on the graph is carbon dioxide a limiting factor?

  • X only

  • X and Y

  • Y and Z

  • Z only

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7
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Higher Tier Only

The inverse square law in relation to light intensity (i) and distance (d) from the light source is shown by:

  • i ∝ d2

  • i ∝ 1/d2

  • i2 ∝ 1/d

  • i2 ∝ d

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8
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Higher Tier only

A light source is placed 0.5m from a plant. The relative light intensity falling on the plant is 2 units.

The light source is moved to 1m away.

What is the relative light intensity falling on the plant now?

  • 0.125

  • 0.25

  • 0.5

  • 1.0

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