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Most Important Plant Physiology mcqs
Plant physiology is the science that is connected to the material and energy exchange, growth and development, as well as movement of plants. Plant physiology is the science that studies plant function—what is going on in plants that accounts for their being alive (Salisbury and Ross, 1992).
Another definition of plant physiology by Taiz and Zeiger (2010) is the study of plant function, encompassing the dynamic processes of growth, metabolism, and reproduction in living plants. In this article, we will explore the most important plant physiology MCQs that will be helpful in your exam.
Most important Bryophytes MCQ's Most important Pteridophytes MCQ's
a. Small pores in epidermis of leaf is called stomata.
b. Guard cells present in the stomata are helpful in exchange of gases with atmosphere.
c. Transpiration takes place through stomata.
(a) a and b
(b) a and c
(c) b and c
(d) a, b and c
Answer : (d)
2.The sub-apical elongation in plants is induced by
(a) Auxins
(b) Gibberellins
(c) Cytokinin
(d) Ethylene
Answer: (b)
3. ATP molecules required for synthesis of a glucose molecule in Calvin-Benson cycle are
(a) 6
(b) 38
(c) 12
(d) 18
Answer: (d)
4. Number of oxygen molecules required during glycolysis of one glucose molecule is
(a) zero
(b) one
(c) six
(d) four
Answer: (a)
5. During the 'Z' scheme of Photosynthesis electrons of which of these reduce NADP+
(a) Photosystem-I
(b) Water
(c) CO2
(d) Photosystem-II
Answer: (b)
6. In the context of respiration, the stage known as glycolysis involves the breaking down of ___ to pyruvic acid.
(a) lactic acid
(b) fructose
(c) citric acid
(d) glucose
Answer: (d)
7. RuBisCO is the most abundant enzyme in the world because:
(a) It is required by the green plants for photosynthesis.
(b) It can absorb maximum CO2 during photosynthesis.
(c) Its active site can bind with both CO2 and O2 and is found in leaves.
(d) It can release oxygen from all the plants in the world.
Answer: (c)
8. What is the correct sequence of cytochromes in ETS?
(a) c1, c, b, a3, a
(b) n, c1, c, a3, a
(c) b, c1, c, a3, a
(d) c1, b, c, a, a3
Answer: (c)
9. Match the following classes of terpenes and their ecological significance
Group I Group II Group III
1. Monoterpenes A. β-Carotene P. Membrane Component
2. Diterpenes B. Pyrethroids Q. Plant Pigment
3. Triterpenes C. Dihydroleucodine R. Insecticidal activity
4. Tetraterpenes D. Sitosterol S. Antioxidant
Identify the correct:
(a) 1-B-R; 2-C-S; 3-D-P; 4-A-Q
(b) 1-D-P; 2-B-R; 3-C-S; 4-A-Q
(c) 1-D-Q; 2-G-P; 3-B-P; 4-A-R
(d) 1-A-S; 2-G-P; 3-B-S; 4-D-P
Answer: (a)
10. Which element is essential for activating the enzyme but not a pert of enzyme?
(a) Mn
(b) Mg
(c) K
(d) Co
Answer: (c)
11. In photosynthesis which element is essential for evolution of oxygen
(a) Cl
(b) Mg
(c) Fe
(d) All of the above
Answer: (a)
12. Main source of elements for nitrate reductase is ferredoxin which is present in
(a) Endoplasmic reticulum
(b) Mitochondria
(c) Chloroplast
(d) Golgi complex
Answer: (c)
13. Which plants Scotoactive stomata perform
(a) C3 photosynthesis
(b) C4 Photosynthesis
(c) Both A and B
(d) CAM Photosynthesis
Answer: (d)
14. The best light f0r stomata opening is
(a) Red
(b) Yellow
(c) Green
(d) Blue
Answer: (d)
15. Sub epidermal evaporation of water exhibit in plant during
(a) Photosynthesis
(b) Guttation
(c) Respiration
(d) Transpiration
Answer: (d)
16.Terpenes constitute a large class of natural products built up from isoprene units. Terpenes are technically only hydrocarbons. The basic molecular formula of terpenes are multiples of (C H )n Where 'n' is the 5 8 number of linked isoprene units. Thus terpenes are also termed isoprenoid compounds. There are two biosynthetic pathways for the terpenes-MVA (mevalonic acid) pathway and MEP (Methylerythritol Phosphate) pathway. Which of the following is incorrect regarding terpenes Biosynthesis
(a) In the MVA pathway, acetyl-coenzyme A acts as a precursor. Two molecules of acetyl-CoA are joined together to form mevalonic acid. This key six-carbon molecule is then pyrophosphorylase, decarboxylated, and dehydrated to yield isopentenyl pyrophosphate (IPP).
(b) In the MVA pathway, IPP isomerizes to dimethylallyl pyrophosphate (DMAPP). DMAPP acts as the prenyl donor to a molecule of IPP producing geranyl pyrophosphate (GPP) by a head-to-tail condensation reaction. GPP can then link to another molecule of IPP to give the 15-Carbon compound farnesyl pyrophosphate, the precursor of nearly all the sesquiterpenes
(c) In the MVA pathway, IPP isomerizes to dimethylallyl pyrophosphate (DMAPP). DMAPP acts as the prenyl donor to a molecule of IPP producing geranyl pyrophosphate (GPP) by a head-to-tail condensation reaction. GPP can then link to another molecule of IPP to give the 15-Carbon compound farnesyl pyrophosphate, the precursor of nearly all the sesquiterpenes.
(d) In MEP pathways, Glyceraldehyde-3-phosphate and two carbon atoms derived from pyruvate appear to combine to generate an intermediate that is eventually converted to IPP.
Answer: (a)
17.Which of the following is an inhibitor of Gibberellin biosynthesis
A. Ancymidol (A-Rest)
B. Paclobutrozol (Bonzi)
C. Quercetin (Flavonol)
D. Genistein
(a) A and B
(b) B and C
(c) C and D
(d) D and A
Answer: (a)
18. The precursor of phytochromobilin is
(a) S- aminole vulinic acid
(b) Lysophosphatidic acid
(c) Phosphatidic acid
(d) Stearic acid
Answer: (a)
19. In photosynthesis, the light-dependent reaction take place on the thylakoid membranes. The inside of the thylakoid membrane is called the lumen, and outside the thylakoid membrane is the stroma, where the light-independent reaction takes place. Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
(a) Electron and H+
(b) ATP and NADPH
(c) CO2 and Glucose
(d) RUBP and PGA
Answer: (b)
20. Which of the following statements describes the functioning of photosystem II?
(a) The splitting of water yields molecular carbon dioxide as a byproduct.
(b) The P680 chlorophyll donates a pair of protons to NADPH, which is + thus converted to NADP+
(c) The electron vacancies in P680 are filled by electron derived from water
(d) Light energy excites electrons in the electron transport chain in a photosynthetic unit.
Answer: (c)
Most important Algae MCQ's Most important Plant Taxonomy MCQ's21. Match the following:-
GROUP-1
GROUP-2
(1) GA3
(A) weedicide
(2) Cytokinin
(B) Bolting
(3) Ethylene
(C) Thinning of cotton
(4) 2,4-D
(D) Lateral shoot growth
Identify
the correct:-
(a)
1-B; 2-D; 3-C; 4-A
(b)
1-C; 2-D; 3-B; 4-A
(c)
1-A; 2-B; 3-C; 4-D
(d)
1-D; 2-C; 3-B; 4-A
Answer:
(a)
22. Which of the following is correct regarding photorespiration. Photorespiration lowers the efficiency of photosynthesis by preventing the formation of
Which of the following statements is correct regarding calvin cycle.
(a) The Calvin cycle is a metabolic pathway by which plants convert CO2 and water into carbohydrates.
(b) The Calvin cycle is a metabolic pathway by which plants convert CO2 into pentose sugars as the main product.
(c) The Calvin cycle enzyme are more reactive if there is a decrease in light intensity
(d) In the Calvin cycle, rubisco adds CO2 to 3-phosphoglycerate.
Answer: (c)
23. Identify the correct sequence of events in cytokinin signaling pathway.
(a) Receptor binding → phosphorylation of AHP protein → phosphorylation of an aspartate residue→ activation of his kinase.
(b) Receptor binding → phosphorylation of AHP protein → activation of his kinase → phosphorylation of an aspartate residue.
Answer: (d)
24. Consider the following statements regarding C4 plants and find correct
(a) C4 plants mainly occur in areas of high temperature and light intensity
(b) C4 plants minimize the oxygenase activity of RUBisCO by fixing CO2 into oxaloacetate.
(c) C3 plants are more efficient in photosynthesis than are C4 plants.
(d) C4 plants minimize the oxygenase activity of RUBisCO by fixing CO2 into phosphoenolpruvate.
Answer: (b)
25. Consider the following statements regarding the auxin signaling pathway.
(A) in the absence, if auxin, AUX/IAA protein remains bound to ARFs (auxin response factors ) and prevents their function.
(B) In the presence of auxin, auxin induces the ubiquitin-proteasome pathway-mediated degradation of AUX/IAA protein and releases ARFS-
(C) ARFs in dimmer form bind to TGT CTC containing AuxRE (Auxin Response Element) in auxin response gene promoter.
Identify the correct statements:-
(a) A and B
(b) B and C
(c) C and D
(d) A,B and C
Answer: (d)
26. Find out the correct order of event occurred during Light reaction
A. P700 → A0 → A1 → FeSx →FeSA → FeSB → Fd → Cytb6 → Cytf → PC
B. P700 →FeSx →FeSA →A0 →A1 →Fd →Cytb6 →Cytf →PC
C. P680 → Pheo → QA → QB → Cytb6f → PC → P700 → A0 → A1 → FeSx →FeSA →FeSB →Fd →FNR
D. P680 → Pheo → QA → QB → PC → Cytb6f → P700 → Ao → A1 → FeSx →FeSA → FeSB →Fd →FNR
(a) A and C
(b) B and C
(c) C and D
(d) B and D
Answer: (a)
27.Consider the following statements regarding abscisic acid (ABA)
A. Seed dormancy is controlled by the ratio of ABA and gibberellin.
B. ABA inhibits gibberellin-induced enzyme production.
C. ABA promotes shoot growth and inhibits root growth at low water potentials.
D. ABA-promotes leaf senescence independent of ethylene.
Identify the correct statements
(a) ABC
(b) BCD
(c) ABD
(d) ABCD
Answer: (c)
28. Which of the following statement is incorrect regarding the light-dependent reactions of photosynthesis
(a) When light strikes on chlorophyll A, electrons enter to electron transport chain
(b) They take place in the thylakoid membrane of the granna
(c) 3-Phosphoglycerate, A 3-Carbon sugar is produced
(d) Carotenoids are accessory pigments
Answer: (c)
29. Following are a few statements regarding the water potential of soil.
P. The osmotic potential (ys ) of soil water is generally negligible, except in s saline soils.
Q. The osmotic potential (ys ) of saline soil is always more than zero. s
R. In dry soils the hydrostatic pressure (yP ) of soil water potential is always p positive.
S. Gravitational potential (yg ) of soil water is always proportional to the height g of the tree.
Which one of the following combinations of the above statements is true?
(a) P and R
(b) Q and S
(c) R and Q
(d) S and P
Answer: (d)
30. Which of the following is correct regarding the rate-limiting enzyme in ethylene biosynthesis is:-
(a) Polygalacturonases
(b) Myoinositol tetracaine phosphate
(c) Alpha aminolevulinic acid
(d) Amino cyclopropane carboxylic acid synthase
Answer: (d)
31. Which of the following is correct regarding the precursor for most of the phenolic secondary metabolites is
(a) Mavalonate
(b) Isopentenyl pyrophosphate
(c) Geranyl phosphate
(d) Phenylalanine
Answer: (d)
32. Which of the following is correct regarding the C4 plant. Which enzyme fixes carbon dioxide in the bundle sheath cell
(a) PEP carboxylase
(b) PEP dehydrogenase
(c) RUBisCo
(d) Malate dehydrogenase
Answer: (c)
33. Which of the following statements are incorrect regarding jasmonic acid biosynthesis.
(a) Action of Lipoxygenase, allenoxide synthase and allen oxide cyclase take place in peroxisome
(b) 12-OXO-phytodienoic acid is produced in chloroplast and transported to the peroxisome
(c) 12-OXO-phytodienoic acid is first reduced and then converted to jasmonic acid by b-oxidation.
(d) The action of Allen oxide synthase and allene oxide cyclase take place in the chloroplast
Answer: (a)
34. Which one of the following statement describes the process of phloem loading?
(a) Those phosphate is transported from the chloroplast to cytosol.
(b) Sugars are transported into the sieve elements and companion cells.
(c) Sugars are transported from producing cells in the mesophyll to cells in the vicinity of the sieve elements.
(d) Solutes are transported from roots to the shoots.
Answer: (b)
35. Which one of the following essential micronutrients are associated with the urease enzyme found in higher plants?
(a) Nickel
(b) Molybdenum
(c) Zink
(d) Copper
Answer: (b)
Most important Gymnosperms MCQ's Most important Pteridophytes MCQ's