Physiology of Plants MCQs Part I

1) Which one of the following is the energy currency of a cell ?
a) Mitochondria
b) Golgi bodies
c) DNA
d) ATP molecules

2) Energy transfers or transformations are never 100% efficient. This is due to
a) Entropy
b) Homeostasis
c) Aggregation
d) Adaptation

3) What type of energy is needed to make up the loss of energy in a living system?
a) Heat Energy
b) Light Energy
c) Free Energy
d) Mechanical Energy

4) Bamboos are
a) Monocarpic
b) Polycarpic
c) Both A and B
d) None of the above

5) Photosynthesis refers to
a) Catabolism
b) Anabolism
c) Both A and B
d) None above

6) Photophosphorylation means
a) Synthesis of NADP
b) Synthesis of ATP from ADP
c) Synthesis of PGA
d) Synthesis of ATP from ADP in presence of light

7) What is the advantage of glycolysis, since it taps only a small fraction of the energy available in the glucose molecule?
a) It may be used when oxygen is unavailable
b) It is cyanical, so that less substrate is required
c) It requires no involvement of ATP
d) It is composed only of spontaneous reaction

8) The plant process most immediately affected by destruction of ATP in cells will be
a) Diffusion
b) Diffusion of gases
c) Active transport
d) Osmosis

9) concentration
in air is %

a) 0.034
b) 0.34
c) 3.4
d) None of above

10) The ultimate source of energy is
a) Sunlight
b) ATP
c) Food
d) Glucose

11) 99% of a living system is formed of the four elements

12) Life without air is
a) Impossible
b) Anaerobic
c) Reductive
d) Free from oxidation

13) Respiration refers to
a) Catabolism
b) Anabolism
c) Metabolism
d) Phototropism

14) If all microorganisms (fungi and bacteria) on earth were destroyed

a) We would not be able to produce antibiotics
b) The earth would be covered by dead bodies
c) There would be no diseases and all life forms would become immortal
d) Soil nitrogen would be depleted.

concentration of the atmosphere remain constant in the atmosphere even
when it is given out in respiration, because

a) Forms carbonate rocks
b) Acts as a buffer
c) Is utilized again in photosynthesis by green plants to form carbohydrates.
d) Is split up during photosynthesis

16) The two life processes that maintain a balance of carbon dioxide and oxygen in nature are
a) Photosynthesis and digestion
b) Respiration and digestion
c) Excretion and respiration
d) Respiration and photosynthesis

17) What type of guard cells are generally found in grasses?
a) Kidney shaped
b) Ring shaped
c) Dumb-bell shaped
d) Pear shaped

18) In terrestrial plants, which cells of a leaf epidermis possess chloroplasts?
a) Stomata
b) Guard cells
c) All epidermal cells
d) Bulliform cells

19) Which of the following type of openings on the surface of a plant is
exclusively meant for the respiratory exchange of gases?

a) Hydathode
b) Stomata
c) Lenticel
d) Pit

20) In Nymphaea, the stomata are present on
a) the adaxial (upper surface) of leaf
b) the abaxial (lower surface) of leaf
c) both the surfaces of leaf
d) None of the above

21) In submerged hydrophytes, stomata are found
a) On the upper surface of the leaf
b) On the lower surface of the leaf
c) On both surfaces of the leaf
d) Nowhere on the plant

22) Collenchymatous hypodermis is a characteristic feature of the
a) Dicot stem
b) Monocot stem
c) Monocot as well as dicot stem
d) Hydrophytes

23) Passage cells are present in the
a) Epidermis
b) Endodermis
c) Xylem
d) Lenticels and hydathodes

24) Casparian strips of suberin occur in the
a) Epidermis
b) Endodermis
c) Pericycle
d) Phloem

25) The endodermis is a part of the
a) Cortex
b) Stele
c) Pith
d) Pericycle

26) The pericycle of the root is made up of
a) Parenchyma
b) Collenchyma
c) Sclerenchyma
d) Fibres

27) In the root, the pericycle gives rise to the
a) Branch root and cork cambium
b) Cortex and pith
c) Xylem and phloem
d) Epidermis and vascular bundles

28) The origin of the lateral root or secondary root is
a) Exogenous
b) Endogenous
c) Lysigenous
d) Schizogenous

29) Water uptake at the expense of energy by the cell against an osmotic gradient is known as
a) Imbibition
b) Osmosis
c) Active absorption
d) Passive absorption

30) The absorption of water by the roots is increased when the
a) Transpiration rate is less
b) Salt absorption is increased
c) Transpiration rate increases
d) Photosynthetic rate increases

31) In waterlogged soil, plants do not grow properly because
a) the soil does not provide air for respiration
b) the soil is physiologically wet
c) of excessive water
d) of shortage of water

32) Flooding kills plants because
a) the cell sap in plants becomes too concentrated
b) Root respiration ceases
c) the cell sap in plants becomes too dilute
d) Excess water leaches away plant nutrients

33) When the concentration of the soil solutes is low, the absorption of water is
a) Retarded
b) Increased
c) Remains normal
d) Stopped

34) The entry of water from the soil upto the xylem elements of the root is due to the
a) Gradient of suction pressure
b) Turgor pressure
c) Degree of imbibition
d) Concentration of ions in water

35) The root system in a plant is well developed
a) Due to deficiency of auxin
b) Due to deficiency of cytokinins
c) Due to deficiency of minerals
d) For increased absorption of water

36) In plants, water ascends through the
a) Xylem
b) Phloem
c) Pith
d) Stele

37) In plants, water is conducted through the
a) Xylem
b) Phloem
c) Stomata
d) Epidermis

38) In an angiosperm, water is mainly conducted through the
a) Tracheids
b) Vessels
c) Sieve tubes
d) All the above

39) In hollow – hearted trees
a) the root will die first
b) the shoot will die first
c) Both die simultaneously
d) Neither the root nor the shoot would die

40) Wilting of a plant occurs when the
a) Xylem is blocked
b) Phloem is blocked
c) Epidermis and a few roots are removed
d) Pith is removed

41) Which of the following plants would die most rapidly?
a) Hollow hearted plants
b) Girdled plants
c) Pruned plants
d) Deciduous trees

42) The removal of a ring of bark from the trunk of a tree eventually kills it because
a) Water cannot go up
b) Fungi and insects attack exposed parts
c) Food does not travel down and the root becomes starved
d) Air blocks the xylem

43) When the cut stump of a plant is fitted with a manometer, the level of mercury rises due to the accumulation of
a) Water
b) Oxygen
c) Mercury
d) Gas

44) When the stem of a herbaceous plant is cut, water oozes out from the stump due to
a) Guttation
b) Transpiration
c) Root pressure
d) Imbibition

45) Sir J.C. Bose proposed this theory to explain the process of ascent of sap
a) Pulsatory theory
b) Transpiration pull theory
c) Relay pump theory
d) Capillary force theory

46) Root pressure is due to
a) Passive absorption
b) Active absorption
c) Increase in transpiration
d) Increase in photosynthesis

47) The root pressure is maximum when the
a) Transpiration is high and the absorption is very low
b) Transpiration is very low and the absorption is very high
c) Absorption is very high and the transpiration is also very high
d) Absorption is low and the transpiration is also very low

48) The most widely accepted explanation for the ascent of sap in plants is
a) Capillarity/Imbibition
b) the pulsating activity of living cells
c) the role of atmospheric pressure
d) Transpiration-cohesion theory

49) Which of the following contributes most to the transport of water from the ground to the leaves of a tall tree?
a) the breakdown of ATP
b) Root pressure
c) Capillary rise of water in the xylem
d) The cohesion of water and the transpiration pull

50) The transpiration-cohesion-tension theory operates in
a) Active absorption
b) Passive absorption
c) Active and passive absorption
d) None of the above

51) The most accepted theory for the ascent of sap in plants was put forward by
a) J.C.Bose
b) Strasburger
c) Sachs
d) Dixon and Jolly

52) The attractive force of cell walls for water molecules is termed
a) Adhesion
b) Cohesion
c) Osmosis
d) Plasmolysis

53) The force of tension-cohesion exceeds root pressure on a
a) Rainy day
b) Foggy morning
c) Sunny day
d) Full moon night

54) Silica incrustation is found on the leaf surface in
a) Mango
b) Grasses
c) Castor
d) Oleander

55) Cellular respiration is
a) Continuous
b) Intermittent
c) Performed at intervals
d) Carried out when energy is required

56) External respiration is
a) Respiration in skin cells
b) the gaseous exchange between an organism and its external environment
c) Gaseous exchange between cells and tissue fluid
d) Both B and C

57) Tissue respiration denotes
a) Respiration by tissues
b) Gaseous exchanges between cell and tissue fluid
c) Cell respiration
d) Both B and C

58) Usable energy available from respiration is
a) 10%
b) 30%
c) 40%
d) 50%

59) The usable energy of respiration is
a) Immediately consumed in cellular activities

b) Trapped in ATP molecules
c) Stored as heat
d) Used in charging biomolecules into activity

60) In respiration, the energy not captured by ATP is
a) Transferred to organic compounds
b) Converted into heat
c) liberated along with carbon dioxide
d) Transferred to water

61) The difference between respiration and combustion is related to respiration being
a) Multi-step
b) Enzyme controlled
c) Intracellular
d) All the above

62) The most common respiratory substrate is
a) Glucose
b) Sucrose
c) Maltose
d) Glycogen

63) Glycolysis is a process
a) Occurring in the cytosol
b) Using carbohydrate as a substrate
c) Employing fat as a respiratory substrate
d) Both B and C

64) Protoplasmic respiration is respiration
a) Occurring in protoplasm
b) Controlled by genetic factors
c) Occurring outside the mitochondria
d) Employing cellular proteins as respiratory substrate

65) The biological oxidation of a respiratory substrate causes the
a) Gain of oxygen
b) Gain of hydrogen
c) Loss of oxygen
d) Loss of hydrogen

66) Which one yields the highest energy per gram?
a) Carbohydrate
b) Protein
c) Fat
d) Amino acids

67) Which one provides twice as much energy as carbohydrates?
a) Vitamins
b) Proteins
c) Minerals
d) Fats

68) The energy released per gram would be
a) Highest when wheat starch is the respiratory substrate
b) Highest when potato starch is the respiratory substrate
c) Highest when rice starch is the respiratory substrate
d) Same in all the cases

69) More energy is produced in aerobic respiration than anaerobic respiration because in anaerobic respiration
a) Food is incompletely oxidised
b) Very few enzymes are involved
c) Oxygen is not required
d) Alcohol is produced

70) R.Q. stands for
a) Resistance coefficient
b) Replicase concentration
c) Respiratory quotient
d) Reticular concentration

71) R.Q. indicates
a) The effect of temperature
b) The nature of the respiratory substrate
c) The amount of water released
d) The type of alcohol formed

72) In respiration of substrate of organic acids, the R.Q. will be
a) Unity
b) Less than one
c) Zero
d) More than one

73) Which one of the following has the highest R.Q.?
a) Malic acid
b) Protein
c) Fat
d) Starch

74) When the R.Q. is infinity, the type of respiration is
a) Aerobic, carbohydrate
b) Aerobic, fat
c) Aerobic, protein
d) Anaerobic, carbohydrate

75) The amount of energy available per molecule of oxygen used in biological oxidation is
a) 114 kcal
b) 686 kcal
c) 256 kcal
d) 60 kcal

76) The number of ATP formed per molecule of oxygen used in respiration is
a) 16
b) 8
c) 6
d) 4

77) The different steps of aerobic respiration are
a) Glycolysis and oxidative phosphorylation
b) Glycolysis and Krebs cycle
c) Glycolysis, Krebs cycle and terminal oxidation
d) Krebs cycle and terminal oxidation

78) Which is common between aerobic and anaerobic respiration?
a) Similar substrate
b) Glycolysis
c) Pyruvic acid
d) All the above

79) For the start of respiration, a living cell requires
a) Glucose
d) Glucose + ATP

80) Phosphorylation of glucose with the help of ATP and hexokinase produces
a) Glucose 1-phosphate
b) Glucose 6-phosphate
c) Glucose 1,6-diphosphate
d) Fructose, 1,6-diphosphate

81) The number of oxygen molecules required for the glycolytic breakdown of the glucose molecule during aerobic respiration is
a) Zero
b) Three
c) Six
d) Thirty eight

82) Which one is removed from the substrate during glycolysis?
a) Hydrogen
b) Electrons
c) Both A and B
d) Oxygen

83) Which one is inhibited if the cells contain excess of ATP?
a) Krebs cycle
b) Glycolysis
c) Oxidative phosphorylation
d) Electron transport

84) Excess of ATP inhibits
a) Phosphofructokinase
b) Pyruvic dehydrogenase
c) Triose phosphate isomerase
d) Glyceraldehyde phosphate

85) Glycolysis occurs in
a) Anaerobic organisms
b) Muscle cells
c) Procaryotic cells
d) Almost all cells

86) Which one of the following is wrong about glycolysis?
a) It uses ATP
b) It produces ATP
c) The end products are carbon dioxide and water

87) The site of glycolysis or EMP is the
a) Mitochondria
b) Cytoplasm
c) E.R.
d) Ribosomes

88) Phosphoglyceraldehyde and dihydroxy acetone phosphate are
a) Isomers
b) Polymers
c) Tautomers
d) Synonyms

89) Substrate phosphorylation is the formation of
a) ATP
b) AMP
c) ADP
d) Pyruvic acid

90) Which is formed along with ATP in glycolysis?
c) FAD

91) The formation of phosphoenol pyruvate from 2-phosphoglycerate is
a) Dehydration
b) Dehydrogenation
c) Oxidation
d) Hydration

92) During conversion of pyruvic acid into acetyl CoA, pyruvic acid is
a) Reduced
b) Oxidised
c) Isomerised
d) Condensed

93) Oxidation of pyruvate is accompanied by
c) Oxidation of CoA
d) Reduction of CoA

94) Oxidation of pyruvate forms
a) Acetyl CoA
d) All the above

95) The removal of hydrogen and
from a substrate is called

a) Decarboxylation
b) Oxidation
c) Oxidative decarboxylation
d) Reductive decarboxylation

96) Krebs cycle produces

97) A single turn of Krebs cycle yields

98) the enzymes of the citric acid cycle (Krebs cycle) occur in the
a) Outer mitochondrial membrane
b) Inner mitochondrial membrane
c) Inter-membrane space
d) Mitochondrial matrix

99) The tricarboxylic acids of the Krebs cycle are
a) Succinic acid, Fumaric acid and Citric acid
b) Oxalosuccinic acid, Citric acid and a-ketoglutaric acid
c) Citric acid, Isocitric acid and Oxalosuccinic acid
d) Citric acid, Isocitric acid and Oxalosuccinic acid

100) In aerobic respiration, first
is liberated during the

a) Oxidation of pyruvate
b) Decarboxylation of oxalosuccinate
c) Decarboxylation of a-ketoglutarate
d) Alcoholic fermentation


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