Plant Physiology: I. Photosynthesis

21. The most active light for photosynthesis is : [Uttarakhand U.D.A./L.D.A. (Mains) 2006]

(a) Violet light
(b) Red light
(c) Blue light
(d) Green light

Correct Answer: (b) Red light

Solution:The process of photosynthesis takes place only in the visible part (3800Å - 7600Å wavelengths) of the electromagnetic radiations. Best photosynthesis takes place in the red light and next best in blue light while in green light, it is nil. T.W. Engelmann (1888), had shown the action spectrum of photosynthesis in his experiment, in which algae in red light produces more oxygen and represented by the accumulation of more aerobic bacteria, whereas in blue light some fewer numbers of bacteria were accumulated.

22. Which light is most effective in photosynthesis? [U.P. R.O./A.R.O. (Mains) 2014]

(a) Red
(b) Blue
(c) Green
(d) Violet

Correct Answer: (a) Red

Solution:The process of photosynthesis takes place only in the visible part (3800Å - 7600Å wavelengths) of the electromagnetic radiations. Best photosynthesis takes place in the red light and next best in blue light while in green light, it is nil. T.W. Engelmann (1888), had shown the action spectrum of photosynthesis in his experiment, in which algae in red light produces more oxygen and represented by the accumulation of more aerobic bacteria, whereas in blue light some fewer numbers of bacteria were accumulated.

23. What rays of sunlight are mostly utilized by chlorophyll in photosynthesis? [Uttarakhand P.C.S. (Pre) 2010]

(a) Red
(b) Yellow
(c) Green
(d) Blue

Correct Answer: (a) Red

Solution:The process of photosynthesis takes place only in the visible part (3800Å - 7600Å wavelengths) of the electromagnetic radiations. Best photosynthesis takes place in the red light and next best in blue light while in green light, it is nil. T.W. Engelmann (1888), had shown the action spectrum of photosynthesis in his experiment, in which algae in red light produces more oxygen and represented by the accumulation of more aerobic bacteria, whereas in blue light some fewer numbers of bacteria were accumulated.

24. Artificial light can — [U.P. Lower Sub (Spl) (Pre) 2008]

(a) Destroy chlorophyll
(b) Synthesise chlorophyll
(c) Bring about photosynthesis
(d) Not bring about photosynthesis

Correct Answer: (c) Bring about photosynthesis

Solution:In the process of photosynthesis, light energy changes into the chemical energy. Normally plants utilize sunlight but marine algae also use moonlight. Photosynthesis even occurs in electric light.

Bioreactors using various models can mimic the actual photosynthesis. It seeks to overcome the limitations of natural photosynthesis such as low efficiency in solar energy capturing and reduction of carbon dioxide.It can provide an alternative route of food security and climate mitigation.Several systems have been demonstrated to convert carbon dioxide and water into various reduced species - Carbon Monoxide, methanol, formate, and hydrogen.

Research at JNCASR (India): Scientists at Jawaharlal Nehru Centre for Advanced Scientific Research have converted the carbon dioxide to carbon monoxide and water by using photosensitiser (ruthenium bipyridyl complex) and enzyme complex (rhenium carbonyl complex).

25. Which one of the following energy conversions takes place in carrying out the process of photosynthesis? [U.P.P.C.S. (Pre) 1998]

(a) Light to chemical energy
(b) Light to thermal energy
(c) Thermal to biochemical energy
(d) Heat to kinetic energy

Correct Answer: (a) Light to chemical energy

Solution:Photosynthesis is the process used by plants to convert light energy into chemical energy. Photosynthesis can be represented by using following chemical equation:
6CO₂ + 12H₂O ⟶ (Sunlight/Chlorophyll) ⟶ C₆H₁₂O₆ + 6H₂O + 6O₂
Where CO₂ = Carbon dioxide, H₂O = Water, C₆H₁₂O₆ = Glucose, O₂ = Oxygen

26. In the process of Photosynthesis, how many molecules of A.T.P. are involved in the synthesis of each molecule of Glucose? [Chhattisgarh P.C.S. (Pre) 2020]

(a) 16
(b) 18
(c) 20
(d) 24

Correct Answer: (b) 18

Solution:In the process of photosynthesis, 18 molecules of A.T.P., 6 molecules of CO₂ and 12 molecules of NADPH are involved in the synthesis of each molecule of Glucose.

Significance of Photosynthesis: It is the bedrock of the existence of living beings as it has multiple ecological significance such as:

Carbon cycle: Carbon compounds are interchanged among the biosphere and atmosphere of the earth through the process of Photosynthesis.

Base for higher trophic levels: Green plants being autotrophs create a base for energy flow to higher trophic level heterotrophic organisms.

Carbon fixation: Plants fix carbon from carbon dioxide into organic molecules through the process of photosynthesis.

Oxygen: Oxygen is a byproduct of Photosynthesis which serves as an essential component of the Respiration process of living beings.

Cyanobacteria and phytoplanktons in the oceans are considered to produce about one-third to one-half of the atmospheric oxygen on the Earth.

27. Solar energy is converted into ATP in : [65ᵗʰ B.P.S.C. (Pre) 2019]

(a) Mitochondria
(b) Chloroplast
(c) Ribosome
(d) Peroxisome

Correct Answer: (b) Chloroplast

Solution:In the process of photosynthesis solar energy is converted into ATP in chloroplast. In light reactions (energy-transduction reactions) of photosynthesis solar energy is converted into chemical energy in the form of two energy-transporting molecules, ATP and NADPH.

28. Light energy changes into the chemical energy by which of the following process: [Uttarakhand P.C.S. (Pre) 2007]

(a) Electrolysis
(b) By photosynthesis
(c) By respiration
(d) By spewing

Correct Answer: (b) By photosynthesis

Solution:In the process of photosynthesis solar energy is converted into ATP in chloroplast. In light reactions (energy-transduction reactions) of photosynthesis solar energy is converted into chemical energy in the form of two energy-transporting molecules, ATP and NADPH.

29. The sunlight energy used by green plants in photosynthesis is transformed into : [M.P. P.C.S. (Pre) 2018]

(a) Chemical energy
(b) Physical energy
(c) Both (a) or (b)
(d) None of the above

Correct Answer: (a) Chemical energy

Solution:In the process of photosynthesis solar energy is converted into ATP in chloroplast. In light reactions (energy-transduction reactions) of photosynthesis solar energy is converted into chemical energy in the form of two energy-transporting molecules, ATP and NADPH.

30. In photosynthesis [Chhattisgarh P.C.S. (Pre) 2017]

(a) Solar energy converts into heat energy
(b) Solar energy converts into kinetic energy
(c) Solar energy converts into potential energy
(d) Light energy converts into mechanical energy
(e) None of the above

Correct Answer: (c) Solar energy converts into potential energy

Solution:In photosynthesis, light energy is converted into chemical energy (and stored), which is a type of potential energy. Chemical energy is stored within the bonds of the atoms and molecules that make up a substance.

Plant Physiology: I. Photosynthesis

21. The most active light for photosynthesis is : [Uttarakhand U.D.A./L.D.A. (Mains) 2006]

22. Which light is most effective in photosynthesis? [U.P. R.O./A.R.O. (Mains) 2014]

23. What rays of sunlight are mostly utilized by chlorophyll in photosynthesis? [Uttarakhand P.C.S. (Pre) 2010]

24. Artificial light can — [U.P. Lower Sub (Spl) (Pre) 2008]

25. Which one of the following energy conversions takes place in carrying out the process of photosynthesis? [U.P.P.C.S. (Pre) 1998]

26. In the process of Photosynthesis, how many molecules of A.T.P. are involved in the synthesis of each molecule of Glucose? [Chhattisgarh P.C.S. (Pre) 2020]

27. Solar energy is converted into ATP in : [65ᵗʰ B.P.S.C. (Pre) 2019]

28. Light energy changes into the chemical energy by which of the following process: [Uttarakhand P.C.S. (Pre) 2007]

29. The sunlight energy used by green plants in photosynthesis is transformed into : [M.P. P.C.S. (Pre) 2018]

30. In photosynthesis [Chhattisgarh P.C.S. (Pre) 2017]

Related Posts