This set of Life Sciences Interview Questions and Answers for freshers focuses on “Photosynthesis – 2”.
1. What is the absorption spectrum?
a) The graph produced by absorption of light
b) The graph shows the photochemical reaction
c) The graph produced by absorption of oxygen
d) The graph shows oxygen evolution at a different wavelength
Explanation: Absorption spectrum is the graph showing the absorption of light by the pigment as the function of the wavelength. Photosynthetic pigment absorbs light in the visible and infrared region.
2. Photosynthetic reaction in an oxygenic photosynthetic organism is performed by pigment ______
a) Chlorophyll b
b) Chlorophyll a
c) Bacteriochlorophyll a
d) Bacteriochlorophyll c
Explanation: Chlorophyll a most effectively absorbs the wavelength and drive photochemical reactions in oxygenic organisms. The spectrum which shows the activity of wavelength on photochemical reaction is the action spectrum.
3. Name the filamentous fungi which are used in Engelmann’s experiment to show photosynthetic activity?
a) Rhizopus stolonifer
Explanation: Engelmann determined the first action spectrum by illuminating filamentous fungus (Spirogyra) with white light that had been passed through the prism and showed the evolution of oxygen at a different wavelength.
4. Which of the following term defines the production of heat and light when excited molecule returns to its original state?
c) Intersystem crossing
Explanation: When extra energy converted to heat and light it is called fluorescence while luminescence is the term given to radioactive decay. Intersystem crossing is the conversion of an excited singlet state to the excited triplet state. In phosphorescence light emitted by triplet to ground state transition.
5. What is resonance energy transfer?
a) Transfer of electrons between the molecules
b) The transfer of energy as well as electrons
c) The transfer of electrons but not the energy
d) The transfer of energy but not the electron
Explanation: Resonance energy transfer is also known as a forster transfer where only energy is transferred directly to the neighboring chlorophyll but not the electrons.
6. Which of the following is a Hill reagent?
c) 2, 6- dichlorophenolindophenol
d) Nicotinamide adenine dinucleotide phosphate
Explanation: When the electrons transferred from water to non-physiological oxidant by the effect of light it is known as Hill reaction and the non-physiological oxidant is called Hill reagent (2, 6- dichlorophenolindophenol).
7. How many photons are absorbed to produce one molecule of oxygen?
Explanation: One molecule of oxygen is produced by the absorption of a minimum eight photos. For the production of oxygen about 300 or more chlorophyll molecules operate together as one photosynthetic unit.
8. Water is used as an electron donor in anoxygenic photosynthesis.
Explanation: Water does not act as an electron donor in anoxygenic photosynthesis as oxygen is not produced by the light energy; it is only converted to ATP while in oxygenic photosynthesis light energy is used to produce oxygen along with ATP.
9. What is red drop phenomenon?
a) Falling of red color in the spectrum
b) Drop in quantum yield in the red region of the spectrum
c) Drop in quantum yield in the far-red region of the spectrum
d) Falling of far-red color in the spectrum
Explanation: Red drop phenomenon describes the drop of quantum yield in far-red region i.e. above 680nm wavelength. It was observed that quantum yield remain same till 680nm and after that, it declined sharply.
10. Which of the following correctly defines the yield of oxygen by the no. of photons absorbed?
a) Emerson enhancement effect
b) Quantum requirement
c) Photochemical reaction
d) Quantum Yield
Explanation: Quantum yield is also known as photosynthetic efficiency which describes the no. of oxygen molecules produced by the absorption of photons.
Sanfoundry Global Education & Learning Series – Life Sciences.
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