Practise defining photosynthesis, writing its equations and analysing investigations involving light, chlorophyll, carbon dioxide, oxygen production and limiting factors.
Which substance is used up in photosynthesis?
chlorophyll
light
oxygen
water
The following can be used to write a word equation for photosynthesis.
1 carbon dioxide and water
2 light and chlorophyll
3 glucose and oxygen
Which shows a correct word equation for photosynthesis?
in the presence of 3
in the presence of 2
in the presence of 1
in the presence of 2
Which structure contains the pigment that transfers energy from light into chemical energy?
chloroplast
mitochondrion
nucleus
ribosome
Fig. 4.1 is a photograph of a water lily, Nymphaea alba, in a lake.
Fig. 4.1
Fig. 4.2 is a photomicrograph of a cross-section of part of a water lily leaf.
A green pigment is found in tissue B in Fig. 4.2.
Describe the function of this pigment.
State the balanced chemical equation for photosynthesis.
Scientists investigated the effect of cuticle thickness on water loss from the leaves of the balsam fir tree, Abies balsamea.
The leaves were divided into three groups:
A - thick cuticle
B - medium cuticle
C - thin cuticle
Samples of leaves from each group were weighed. The leaves were placed on a tray in dry air at . The samples of leaves were reweighed, at intervals, over 15 hours. The scientists calculated the mass of each sample of leaves as a percentage of the initial mass.
mass of the leaves as a percentage of the initial mass
Fig. 5.1 shows the results.
Water is one of the raw materials needed for the production of sugars in photosynthesis.
State three ways a plant uses the sugars produced in photosynthesis.
Some algae are single-celled organisms that can photosynthesise. Their cells contain the pigment chlorophyll.
State the name of one mineral ion that is needed to make chlorophyll.
A plant with variegated leaves was placed in a dark cupboard for 48 hours so that all the starch was removed from the leaves. The variegated leaves have green parts and white parts.
Black paper was then fixed on one leaf and the plant was exposed to the light.
After 24 hours, which region of the leaf contained starch?
The diagram shows an experiment investigating the effect of light intensity on an aquatic plant.
Photosynthesis occurred in both test-tube P and test-tube Q . Both test-tubes were kept at the same temperature. The number of bubbles produced in test-tube P was 12 bubbles per minute.
What is the most likely number of bubbles produced in one minute in test-tube Q ?
0
3
12
48
A student investigated the effect of light on photosynthesis in algae, using hydrogencarbonate indicator solution.
Carbon dioxide is an acidic gas.
Table 4.1 shows the colour of the hydrogencarbonate indicator solution at different pH values.
Table 4.1
Two test-tubes were set up at the same time. Both contained algae and hydrogencarbonate indicator. At the start of the investigation the hydrogencarbonate indicator was red in both test-tubes.
One test-tube was placed in the dark and one test-tube was placed in the light.
After 20 minutes, the contents of the test-tube in the dark were yellow and the contents of the test-tube in the light were purple.
Explain these results.
A student investigated the effect of light on photosynthesis in algae, using hydrogencarbonate indicator solution.
Carbon dioxide is an acidic gas.
Table 4.1 shows the colour of the hydrogencarbonate indicator solution at different pH values.
Table 4.1
Fig. 4.1 is a graph showing the effect of light intensity on the rate of photosynthesis.
Fig. 4.1
State which factors could be limiting the rate of photosynthesis at X and at Y in Fig. 4.1.