It was observed that the mutant tobacco plants had a faster growth rate than the normal tobacco plants.
Suggest explanations for this observation.
Identify three similarities between the artificial photosynthesis process shown in Fig. 4.1 and the normal process of photosynthesis.
Fig. 4.2 shows the single-celled alga Chlamydomonas. It contains a large, cup-shaped chloroplast for photosynthesis.
Structures A and B in Fig. 4.2 are found within the chloroplast.
Name structures A and B.
A _____
B _____
Some of the protein components of the thylakoid membrane have a role in the
light-dependent stage of photosynthesis.
Explain the roles of the different proteins that function in the light-dependent stage of photosynthesis.
The products of the light-dependent stage of photosynthesis are used in the Calvin cycle. Calvin cycle intermediates are used to produce amino acids, carbohydrates and lipids.
Name the Calvin cycle intermediate that can be used to produce starch.
Scientists claim that the artificial photosynthesis process shown in Fig. 4.1 is more efficient at converting light energy into food than normal photosynthesis by crop plants.
Give reasons why this claim may or may not be true.
true _____
not true _____
Paper chromatography is a technique that can be used to separate a mixture of four common chloroplast pigments. The pigments can be identified by calculating their values.
A student carried out paper chromatography on a solution containing a mixture of chloroplast pigments.
The results are shown in Table 7.1.
Table 7.1
| pigment | distance travelled by pigment from baseline / cm | distance travelled by solvent from baseline / cm | |
|---|---|---|---|
| ______ | 6.5 | 8.9 | 0.73 |
| chlorophyll a | 4.6 | 8.9 | 0.52 |
| chlorophyll b | ______ | 8.9 | 0.38 |
| carotene | 8.2 | 8.9 | ______ |
Complete Table 7.1.
Fig. 7.1 shows the absorption spectrum for carotene and for chlorophyll a.
With reference to Fig. 7.1, describe and explain the role of carotene in photosynthesis.
Fig. 9.1 is a diagram outlining non-cyclic photophosphorylation.
With reference to Fig. 9.1, describe the process of non-cyclic photophosphorylation.
Fig. 9.2 shows the relationship between the rate of photosynthesis and light intensity.
Describe and explain the relationship shown in Fig. 9.2.
Suggest and explain why the curve shown in Fig. 9.1 for the absorption spectrum is different from the curve for the action spectrum for wavelengths of light between 450 nm and 550 nm.
With reference to Fig. 9.2, describe and explain the effect of temperature on the rate of photosynthesis for K. procumbens.
The rate of photosynthesis in this investigation was obtained by measuring the uptake of carbon dioxide from the atmosphere. It did not take into account the use of carbon dioxide produced by respiration.
Using Fig. 9.2, calculate the rate of photosynthesis at 20°C when the carbon dioxide produced by respiration is taken into account.
rate of photosynthesis = ______
Cyclic photophosphorylation and non-cyclic photophosphorylation occur during the light-dependent stage of photosynthesis.
Outline the differences between cyclic photophosphorylation and non-cyclic photophosphorylation.
Complete the passage about the Calvin cycle using the most appropriate word or words.
A molecule of ______ combines with a five-carbon molecule, ribulose bisphosphate (RuBP), catalysed by the enzyme ______. This reaction produces a six-carbon compound that splits into two molecules of a three-carbon compound, glycerate 3-phosphate (GP).
ATP and ______ are used to convert GP molecules into molecules of a three-carbon sugar, triose phosphate (TP).
Some TP molecules are used to make ______, while others are recycled to regenerate RuBP using ATP.
With reference to the light-dependent stage of photosynthesis, explain the differences between the results shown in Fig. 7.1 for red light and for green light.
Changes in the atmospheric carbon dioxide concentration, light intensity and temperature can affect the rate of photosynthesis. These three factors directly affect different processes of photosynthesis.
Complete Table 7.1 using a tick (✓) to identify the processes that can be directly affected by each factor or a cross (✗) to identify the processes that are not directly affected by each factor.
Indirect effects where a change in the rate of one process affects the rate of a different process should not be considered.
A tick or a cross must be placed in the final column of every row.
Table 7.1
| factor | process | ✓ or ✗ |
|---|---|---|
| carbon dioxide concentration | Calvin cycle | ______ |
| photophosphorylation | ______ | |
| light intensity | Calvin cycle | ______ |
| photophosphorylation | ______ | |
| temperature | Calvin cycle | ______ |
| photophosphorylation | ______ |
The group of proteins labelled C, PSI and the protein labelled E are involved in a specific biochemical process during the light-dependent stage of photosynthesis.
Name this specific biochemical process and the protein labelled E.
process ______
E ______
Product D is used during the Calvin cycle.
Identify product D and describe its specific role in the Calvin cycle.
Limiting factors affect the rate of photosynthesis.
Describe and suggest how the results for tropical forest, temperate forest and snow forest in Fig. 5.2 show the effect of limiting factors on photosynthesis.
Suggest reasons why grasslands and desert have a lower rate of energy transfer by photosynthesis than forests.
Use Table 7.1 to calculate the rate of photosynthesis at a light intensity of 6 lux.
Complete Table 7.1 by writing your calculated value in the space provided.
Plot a graph of the data in Table 7.1 on the grid in Fig. 7.1 to show the effect of light intensity on the rate of photosynthesis.
Draw a curve and extend your curve to show what would happen to the rate of photosynthesis if the experiment is carried out at 18 lux.
Fig. 7.1
In photophosphorylation, photoactivation of chlorophyll results in the synthesis of ATP.
Describe how photoactivation of chlorophyll results in the synthesis of ATP in photophosphorylation.