Biology MCQs for NEET Exam on “Photosynthesis Basics – 2”.
1. The following diagram represents ______
a) Joseph Priestly experiment
b) Gregor Mendel experiment
c) Engelmann experiment
d) Linnaeus experiment
Answer: a
Clarification: This shows the Joseph Priestly experiment. Here, (a) and (b) shows that when a mouse and a candle is placed in a jar without air, the mouse dies. Whereas, (c) and (d) shows that when a mint plant is placed along with the mouse and candle, we can see that the mouse is still alive. The plant restores the oxygen inside the jar.
2. During which year, Joseph Priestley discovered O2?
a) 1774
b) 1770
c) 1884
d) 1880
Answer: a
Clarification: Joseph Priestley discovered O2 in 1774. He found the presence of oxygen during his experiment. In a jar containing a mouse, a candle and a mint plant, he found out that the mouse was alive and the candle was lit up. This showed that the mint plant gave oxygen to the enclosed jar.
3. Photosynthesis is the basis of life on earth because ______
a) It is the main source of all food on earth
b) It helps in the release of CO2 into the atmosphere
c) It produces new offsprings
d) It gives no energy to plants
Answer: a
Clarification: Photosynthesis is the basis of life on earth because it is the main source of all food on earth. It is also responsible for the release of oxygen into the atmosphere. It does not produce new offsprings but gives energy or glucose to the plants in the form of starch.
4. Other than CO2 and light, which is used as the raw material for photosynthesis?
a) O2
b) CO2
c) H2O
d) MnO2
Answer: c
Clarification: The raw materials of photosynthesis are carbon dioxide and water in the presence of sunlight. And its final products are glucose, water, and oxygen. These substances are the most abundant materials on earth and provide equivalent oxygen to atmosphere.
5. Among the following, which compound does not play an important role in photosynthesis?
a) Xanthophyll
b) Anthocyanin
c) Chlorophyll
d) Phycoerythrin
Answer: b
Clarification: Anthocyanin does not play an important role in photosynthesis whereas the others have an important role. Anthocyanin main role is to provide blue, red and purple color to the plants. It also protects the plants from high temperatures and abiotic stresses.
6. What do we call the organism that does photosynthesis but does not release oxygen?
a) Green sulfur bacterium
b) Blue-green algae
c) Green algae
d) Green plants
Answer: a
Clarification: Green sulfur bacterium does photosynthesis but does not release oxygen. They are anoxygenic. They use H2S as a substitute for water and utilize sulfide ions to form sulfur and water. No oxygen is formed.
7. In photosynthesis, the carbon dioxide is oxidized and water is reduced.
a) True
b) False
Answer: b
Clarification: It is a wrong statement. Here in photosynthesis, the carbon dioxide is reduced and water is oxidized. Carbon dioxide is reduced to glucose whereas water is oxidized to oxygen.
8. Who found out that oxygen evolved from water in photosynthesis?
a) T. W. Engelmann
b) C. Van Neil
c) R. Hill
d) Ruben and Kamen
Answer: c
Clarification: R. Hill found out that oxygen evolved from water in photosynthesis. It was believed that oxygen came from carbon dioxide. Later, Hill’s reaction showed that oxygen was produced from water.
9. What were the isotopes used, to research about photosynthesis?
a) 11C and 32P
b) 15C and 35Cl
c) 13C and 14N
d) 14C and 18O
Answer: d
Clarification: 14C and 18O were the isotopes used to research about photosynthesis. A plant undergoing photosynthesis produces more 18O than normal oxygen. Also, 14C was used to estimate the presence of carbon atoms in the photosynthesis process.
10. Why is light energy used in photosynthesis?
a) Reduction of H2O
b) Reduction of CO2
c) Activation of chlorophyll
d) Oxidation of C6H12O6
Answer: c
Clarification: Light energy is mainly used in photosynthesis for activation of chlorophyll. Chlorophyll is in an inactive state. It becomes active only in the presence of sunlight. These rays fall on chloroplast which in turn activates the chlorophyll.
11. During photosynthesis, which light is least effective?
a) Greenlight
b) Sunlight
c) Yellow light
d) Blue light
Answer: a
Clarification: Greenlight is the least effective among the following. Greenlight is reflected by green leaves, so cannot be absorbed. But blue light gives maximum absorption peak of chlorophyll and is most effective.
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