Photosynthesis Quiz - ICSE Class 10 Biology

Free practice quiz: Photosynthesis (ICSE Class 10 Biology). 46 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 10 Biology practice quiz has 46 multiple-choice questions on Photosynthesis, and 46 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which of the following molecules is the primary electron acceptor in the light-dependent reactions of photosynthesis?

   1. ATP
   2. NADP+
   3. Glucose
   4. Water
   Show answer

   Answer: B. NADP+

   During the light-dependent reactions, light energy is used to split water molecules and excite electrons. These high-energy electrons are then passed along an electron transport chain, ultimately reducing NADP+ to NADPH. NADPH is a crucial electron carrier that will be used in the Calvin cycle to reduce carbon dioxide into sugars.

2. Which of the following is NOT a pigment involved in photosynthesis?

   1. Chlorophyll a
   2. Carotenoids
   3. Anthocyanins
   4. Chlorophyll b
   Show answer

   Answer: C. Anthocyanins

   Chlorophyll a and b are the primary photosynthetic pigments. Carotenoids are accessory pigments that absorb light in different wavelengths and transfer energy to chlorophyll. Anthocyanins are water-soluble pigments that often contribute to the red, purple, or blue colors of plant tissues but are not directly involved in capturing light energy for photosynthesis.

3. The enzyme catalyzing the reduction of NADP+ to NADPH in the light-dependent reactions is located in:

   1. The stroma of the chloroplast
   2. The lumen of the thylakoid
   3. The thylakoid membrane
   4. The inner mitochondrial membrane
   Show answer

   Answer: C. The thylakoid membrane

   The enzyme NADP+ reductase, which catalyzes the final step of electron transfer to NADP+ to form NADPH, is embedded within the thylakoid membrane. The electrons are passed to it from the electron transport chain, and NADP+ is reduced on the stromal side of the membrane.

4. The bundle sheath cells in C4 plants are characterized by:

   1. High concentrations of PEP carboxylase and low concentrations of RuBisCO.
   2. High concentrations of RuBisCO and low concentrations of PEP carboxylase.
   3. Equal concentrations of PEP carboxylase and RuBisCO.
   4. Absence of both PEP carboxylase and RuBisCO.
   Show answer

   Answer: B. High concentrations of RuBisCO and low concentrations of PEP carboxylase.

   In C4 plants, the spatial separation of carbon fixation ensures that the Calvin cycle occurs in bundle sheath cells. These cells are rich in RuBisCO, the enzyme that fixes CO2 into the Calvin cycle, and are generally low in PEP carboxylase, which is primarily found in the mesophyll cells.

5. Which statement is true regarding the relationship between chlorophyll and accessory pigments in light absorption?

   1. Accessory pigments absorb light energy and pass it to chlorophyll a, broadening the absorption spectrum.
   2. Chlorophyll a is the only pigment that absorbs light directly.
   3. Accessory pigments are located in the stroma, while chlorophyll is on the thylakoid membrane.
   4. Accessory pigments are more efficient than chlorophyll a in converting light energy to chemical energy.
   Show answer

   Answer: A. Accessory pigments absorb light energy and pass it to chlorophyll a, broadening the absorption spectrum.

   Accessory pigments, such as carotenoids and chlorophyll b, absorb light energy at wavelengths that chlorophyll a cannot absorb efficiently. They then transfer this absorbed energy to chlorophyll a molecules in the reaction centers, thereby increasing the overall efficiency of light capture during photosynthesis.

More questions in this quiz

Answers and explanations are in the full quiz.

1. The absorption spectrum of chlorophyll a shows peak absorption in which regions of the visible light spectrum?
2. In C4 plants, the initial fixation of carbon dioxide occurs in which type of cells?
3. The splitting of water molecules during the light-dependent reactions is called:
4. Which enzyme is responsible for the primary carboxylation of RuBP in the Calvin cycle?
5. The products of the light-dependent reactions that are used in the Calvin cycle are:
6. In a CAM plant, stomata are typically open during which time to minimize water loss?
7. Photorespiration is a process that:
8. The primary site of photosynthesis in eukaryotic plant cells is the:
9. The Calvin cycle takes place in which part of the chloroplast?
10. The light-dependent reactions of photosynthesis occur on the:
11. In C3 photosynthesis, the first stable product of carbon dioxide fixation is a:
12. Which factor is most likely to limit the rate of photosynthesis at high light intensities if other factors are not limiting?
13. The regeneration of RuBP in the Calvin cycle requires:
14. The primary function of accessory pigments in photosynthesis is to:
15. What is the net gain of ATP per molecule of glucose produced in aerobic respiration compared to the net gain of ATP per molecule of glucose produced in photosynthesis?
16. The light compensation point in photosynthesis refers to the light intensity at which:
17. In C4 plants, the Calvin cycle occurs in the:
18. Which of the following is the most accurate representation of the overall chemical equation for photosynthesis?
19. The reduction of 3-phosphoglycerate (3-PGA) to glyceraldehyde-3-phosphate (G3P) in the Calvin cycle requires:
20. Which statement best describes the role of the proton gradient across the thylakoid membrane in photosynthesis?
21. The enzyme RuBisCO has a dual function. What are these two functions?
22. What is the fate of the oxygen produced during the light-dependent reactions?
23. Which of the following conditions would most likely lead to an increase in the rate of photosynthesis in a C3 plant, assuming all other factors are optimal?
24. During the synthesis of ATP in the chloroplasts via photophosphorylation, what is the role of the electric potential gradient across the thylakoid membrane?
25. What is the function of NADP+ reductase in photosynthesis?
26. Which of the following best describes cyclic photophosphorylation?
27. In the process of photorespiration, which molecule is consumed, and which gas is released?
28. Which statement accurately reflects the interdependence of light-dependent and light-independent reactions?
29. The primary function of the RuBP carboxylase/oxygenase (RuBisCO) enzyme in the Calvin cycle is to catalyze the:
30. In a thylakoid membrane, the electron transport chain is arranged in such a way that it creates a proton gradient by:
31. In C3 plants, the accumulation of a 4-carbon dicarboxylic acid in mesophyll cells when exposed to light and CO2 indicates:
32. The primary product of the Calvin cycle that can be used to synthesize glucose and other organic molecules is:
33. In the context of photosynthesis, the 'dark reactions' (Calvin cycle) are dependent on the products of the 'light reactions' for:
34. Which cellular compartment is primarily responsible for the synthesis of ATP during the light-dependent reactions of photosynthesis?
35. A key difference between C3, C4, and CAM photosynthesis lies in the spatial or temporal separation of:
36. The enzyme phosphoglycerate kinase catalyzes the conversion of 3-phosphoglycerate to 1,3-bisphosphoglycerate using:
37. What is the primary role of carotenoids in photosynthesis?
38. The overall efficiency of light energy conversion in photosynthesis is typically quite low, often around:
39. Which molecule is regenerated at the end of the Calvin cycle to allow continuous carbon fixation?
40. The initial capture of light energy in photosynthesis occurs at the:
41. In CAM plants, the enzyme PEP carboxylase is active during the night to fix CO2 into:

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