This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Photosynthesis – 1”.
1. Name the physiochemical process in which chemical energy is produced by light energy with the help of a photosynthetic organism?
c) Oxidative decarboxylation
d) Oxidative phosphorylation
Explanation: Photosynthesis is the physiochemical process in which chemical energy is produced by light energy in the form of reducing power (NADPH, ATP) which is used for carbon dioxide fixation.
2. Classification of organisms as oxygenic or anoxygenic during photosynthesis is based on ______
a) The presence of Co2
b) The generation of oxygen
c) The presence of light
d) The presence of water
Explanation: Photosynthetic organisms are classified on the basis of generation of oxygen during photosynthesis, it may be oxygenic or anoxygenic. Oxygenic organisms include both prokaryotes and eukaryotes while anoxygenic organisms are only prokaryotes.
3. Which of the following is an anoxygenic photosynthetic organism?
b) Photosynthetic protists
d) Green and Purple photosynthetic organism
Explanation: Green and Purple photosynthetic organism is an anoxygenic photosynthetic organism while rests are oxygenic in nature. Anoxygenic photosynthetic organisms work under the absence of light and take part in light-independent reactions.
4. Which of the following is not a lipid-soluble photosynthetic pigment?
Explanation: Among all the photosynthetic pigments, only phycobilins are water soluble. This unique feature of phycobilins is due to the presence of water-soluble proteins in their structure.
5. Which of these features are not of chlorophyll?
a) It has Mg2+ as the central metal ion
b) It has cyclopentanone ring fused with a pyrrole ring
c) It has a planer tetrapyrrole ring structure
d) It is water-soluble pigment
Explanation: Water-soluble pigment is not the feature of chlorophyll as it is a lipid-soluble pigment. It consists of a hydrophobic phytol tail which makes it hydrophobic in nature. Due to the hydrophobic character, it is not soluble in water.
6. Name the pigment which is responsible for the yellow color of leaves in autumn and orange color of carrots?
Explanation: Carotenoids distinguished from one another by their end group, these are long-chain, conjugated hydrocarbons whose absorption spectrum lies between 400-500nm which is responsible for yellow as well as orange color in leaves and carrots.
7. Accessory pigments absorb light at more wavelengths as compared to chlorophyll.
Explanation: The presence of conjugated double bond, the isomeric configuration and the end group of accessory pigments makes it absorb light at more wavelength than chlorophyll. The two accessory pigments are phycobilins and carotenoids.
8. Name the mechanism which prevents photo-oxidative damage in plants?
Explanation: Carotenoids are the accessory pigments which protect the plant from oxidative damage, and this phenomenon is known as photoprotection. Lipids and some cellular components get damaged by high-intensity light where carotenoid helps to remove excess energy.
9. Name the photosynthetic pigment which is structurally similar to bile pigment bilirubin?
Explanation: Phycobilins have non-cyclic, linear tetrapyrroles structure which shows the structural similarity to the bile pigment called bilirubin. This is unique photosynthetic pigment which is covalently bound to water-soluble protein, phycobiliprotein.
10. What is the location of photosynthetic pigment in an oxygenic photosynthetic organism?
a) Plasma membranes
b) Thylakoid membranes
Explanation: Photosynthetic pigment of oxygenic organism located in thylakoid membranes while plasma membrane and chlorosome are the locations for storing pigment of green sulfur bacteria. Purple sulfur bacteria store their pigment in chromatophore.
Sanfoundry Global Education & Learning Series – Life Sciences.
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