This set of Plant Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “Photosynthesis”.
1. Who indicated first that water is the electron donor in light reaction of photosynthesis?
a) Daniel Arnon
b) Van Niel
c) Blakeslee
d) Calvin
View Answer
Explanation: Van Niel first indicated that water is the electron donor in the light phase of photosynthesis. Daniel Arnon proposed how light from the sun is converted to ATP by plants.
2. Dark reaction of photosynthesis is so-called because ______
a) It requires light
b) It occurs in the dark
c) It occurs more rapidly at night
d) It is light independent
View Answer
Explanation: Dark reaction of photosynthesis does not require light for the process to occur but occurs in the presence of sunlight and not in dark. That is why this process is called a light-independent step.
3. What is the main substrate for photorespiration?
a) Glycolate
b) Serine
c) Glycine
d) Phosphoglycerate
View Answer
Explanation: Glycolate is the chief substrate for photorespiration and another important metabolite is serine and glycine but phosphoglycerate is not a substrate because it is a lipid.
4. C4 plants have higher net photosynthetic rate because they have __________
a) Kranz anatomy
b) PEP as CO2 receptor
c) No photorespiration
d) Photosynthesis even at a low light intensity
View Answer
Explanation: The net photosynthetic rate in C4 plants is higher because there is no photorespiration and also photosynthesis takes place even at low CO2 concentration. Therefore, photosynthesis is more efficient in C3 plants.
5. Why does chlorophyll appear green?
a) Because it absorbs red and blue regions of light and reflects green light
b) It absorbs green light and reflects green light
c) It absorbs red light and emits green light
d) Transmits green light
View Answer
Explanation: Chlorophyll appears green because it absorbs light in blue and red regions of the visible spectrum and reflects green light and make the plant appear green. It does not absorb and emits green light.
6. Plants store carbohydrate as starch and not glucose because ____________
a) Glucose is unstable
b) Starch is unstable
c) Glucose disturbs the osmotic balance
d) Glucose will be used by plants
View Answer
Explanation: Plants store and transport carbohydrate as starch or sucrose and not glucose because glucose is unstable and starch is more efficient in energy storage. Sucrose enters the phloem for its active transport.
7. In which of the following category of plants, the CAM pathway occurs?
a) Bryophyllum
b) Succulents
c) Mesophytic
d) Angiosperms
View Answer
Explanation: CAM pathway occurs in succulents in which the sunlight is absorbed during day time and this energy is used for CO2 fixation during night time. This pathway is not observed in another type of plants.
8. Which of the following is not an accessory pigment?
a) Chlorophyll a
b) Chlorophyll b
c) Xanthophyll
d) Carotene
View Answer
Explanation: Chlorophyll a is not an accessory pigment as it initiates the reactions of photosynthesis whereas chlorophyll b, Xanthophyll and carotene help in channeling the trapped sunlight towards the reaction center.
9. How many molecules of ATP and NADPH are required for the synthesis of a molecule of glucose respectively?
a) 12 and 22
b) 18 and 12
c) 12 and 32
d) 12 and 8
View Answer
Explanation: 18 molecules of ATP and 12 molecules of NADPH are required for the synthesis of a molecule of glucose. Different steps utilize and release a different number of ATP and NADPH.
10. Which photosynthetic bacteria possess both PSI and PSII for photosynthesis?
a) Purple non-sulfur bacteria
b) Purple sulfur bacteria
c) Green sulfur bacteria
d) Cyanobacteria
View Answer
Explanation: Cyanobacteria possess chlorophyll molecule as well as both the reaction center, PSI and PSII for photosynthesis whereas purple sulfur and non-sulfur bacteria do not show photosynthesis as they lack chlorophyll.
11. The photosynthetic unit present in the thylakoid is known as _________
a) Ribosome
b) Quantosome
c) Liposome
d) Glyoxysome
View Answer
Explanation: Quantosome is the photosynthetic unit present in the thylakoid membrane of chloroplast in which photosynthesis takes place.
12. Oxygen is liberated in which part of photosynthesis?
a) Reduction of CO2
b) Breakdown of glucose
c) Breakdown of proteins
d) Hydrolysis of water
View Answer
Explanation: Hydrolysis of water occurs when the PSII loses its electron and there is a hole left. Hydrolysis of water occurs in the presence of light and releases 2H+, 2O2 and electron.
13. C4 plants are more efficient than C3 plants.
a) True
b) False
View Answer
Explanation: In C4 plants, photorespiration does not occur and also photosynthesis occurs even when the stomata are closed and there is low CO2 concentration. Therefore, the photosynthetic yield is more in C4 plants than in C3 plants.
14. Sugarcane shows the high efficiency of CO2 fixation because it shows ______
a) EMP pathway
b) TCA cycle
c) Calvin cycle
d) Hatch and Slack pathway
View Answer
Explanation: Sugarcane shows the high efficiency of CO2 fixation because it is a C4 plant and shows the Hatch and Slack pathway which is also known as the C4 pathway. The efficiency is less in C3 plants.
Sanfoundry Global Education & Learning Series – Plant Biotechnology.
To practice all areas of Plant Biotechnology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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