Physiology of Plants MCQs Part IV

1) Osmosis involves
a) Cell to cell movement of water
b) Movement of water through cortical cells
c) Active absorption of water through roots
d) All the above

2) Osmosis means
a) The movement of molecules from higher concentration to lower concentration
b) The uptake of water by the roots
c) The passage of solvent from a weaker solution to a stronger solution across a semipermeable membrane
d) The passage of solvent from a weaker to a stronger solution separated by a membrane

3) If a thoroughly cleaned goat bladder is filled with a sugar solution, tightly tied and immersed in a vessel of water
a) The bladder would shrink
b) The volume of the liquid within the bladder will remain constant
c) The volume of liquid within the bladder will increase
d) The volume of liquid within the bladder will decrease

4) Osmotic pressure is highest in
a) Xerophytes
b) Lithophytes
c) Halophytes
d) Mesophytes

5) The process of osmosis involves
a) Movement of solute through a semipermeable membrane
b) Movement of solvent through a semipermeable membrane
c) Movement of solution through a semipermeable membrane
d) None of the above

6) All the following involve osmosis except the
a) Movement of water from the soil to the root
b) Movement of water from the root hair to the endodermis and pericycle
c) Movement of water between the xylem elements
d) Movement of water from the xylem to the mesophyll cells of the leaves

7) The process of osmosis ceases when
a) Water concentrations become equal
b) The leaves fall
c) the solutions are not isotonic
d) There is no light

8) In the process of plasmolysis
a) endosmosis occurs
b) exosmosis occurs
c) imbibition ocurs
d) diffusion occurs

9) A cell increases in volume when it is placed in
a) an isotonic solution
b) a hypertonic solution
c) a hypotonic solution
d) none of these

10) When a cell is kept in 0.5M solution of sucrose, its volume does not alter. If the same cell is placed in 0.5M solution of sodium chloride
a) The cell is plasmolysed
b) There will be no change
c) The cell size would increase
d) The cell size would decrease

11) If a cell is reduced in size when placed in a solution the solution is
a) Hypotonic
b) Hypertonic
c) Saturated
d) Weak

12) The real force causing the entry of water into a cell from other cells is
a) Diffusion pressure deficit
b) Turgor pressure
c) Osmotic pressure
d) Wall pressure

13) The turgidity of a cell is maintained by the
a) Diffusion pressure
b) Wall pressure
c) Osmotic pressure
d) Turgor pressure

14) DPD stands for
a) Diffusion potential deficit
b) Diffusion pressure deficit
c) Daily phosphate demand
d) Daily photosynthetic depression

15) The value of the DPD of a cell is
a) OP x TP
b) OP + TP
c) OP – TP

16) Which of the following is correct?
a) DPD = OP x WP
b) WP = OP – DPD
c) OP = WP – DPD
d) DPD = WP – OP

17) In a plant cell, the osmotic pressure is equal to
a) Turgor pressure – Diffusion pressure
b) DPD + TP
c) DPD – TP
d) Turgor pressure – DPD

18) Under natural conditions, the osmotic pressure is
a) More than the turgor pressure
b) Less than the turgor pressure
c) Equal to the turgor pressure
d) Zero

19) When a cell is fully turgid, which of the following will be zero?
a) Osmotic pressure
b) Turgor pressure
c) Wall pressure
d) Suction pressure (DPD)

20) If a cell A with DPD = 5 atm is surrounded by many cells with DPD = 4 atm
a) The net movement of water will be from cell A to the surrounding cells
b) The net movement of water will be from the surrounding cells to cell A
c) Water movement will depend on other unknown factors
d) Water will not move at all

21) If a plant cell is immersed in water, water continues to move into the cell until
a) The concentration of salt becomes equal
b) The DPD becomes equal
c) The concentration of water is equal on both sides of the cell membrane
d) The cell bursts

22) What would be the direction of the movement of water if two cells have the same OP but differ in TP?
a) No net flow
b) From lower TP to higher TP
c) From higher TP to lower TP
d) Data insufficient

23) Plant cells do not burst even when kept in distilled water because
a) The cell wall is permeable
b) The cell wall is living
c) The cell wall is elastic and rigid and gets stretched
d) Cell wall is dead and impermeable

24) When a plant cell is placed in a solution which is hypotonic to the cell sap, which of the following conditions will not apply?
a) The wall pressure of the cell will fall
b) The cell will become turgid
c) The suction pressure of the cell sap will fall
d) The water potential of the cell sap will rise

25) If a plant cell is immersed in water, the water continues to enter the cell until the
a) Amount of water is the same inside the cell and outside
b) Diffusion pressure is the same inside and outside the cell
c) Concentration of the salt is the same inside as well as outside
d) Cell bursts

26) The diffusion of water through a selectively permeable membrane is known as
a) Active absorption
b) Passive transport
c) Osmosis
d) Diffusion

27) Root hairs occur in the zone of
a) Cell division
b) Cell elongation
c) Cell maturation
d) Calyptrogen

28) A cell kept in a solution draws water and swells up. The nature of this solution is
a) Hypotonic
b) Hypertonic
c) Isotonic
d) More than isotonic

29) The pressure exerted by a swollen vacuole on the cell wall is
a) OP
b) WP
c) TP
d) DPD

30) What maintains the shape of a cell?
a) Osmotic pressure
b) Turgor pressure
c) Suction pressure
d) Wall pressure

31) A cell placed in a strong salt solution will shrink because
a) Salt water enters the cell
b) Water leaves the cell by exosmosis
c) The cytoplasm will decompose
d) Mineral salts will break the cell wall

32) Plasmolysis occurs due to
a) Exosmosis
b) Endosmosis
c) Presence of solutes
d) Semipermeability of cell membrane

33) Grapes immersed in water will shrink if the
a) Water contains salt
b) Water contains starch
c) Water is cold
d) Water is hot

34) What would happens if a formalin-preserved Spirogyra filament is placed in a hypertonic sugar solution?
a) It gains turgidity
b) It loses turgidity
c) It becomes plasmolysed
d) Nothing happens

35) What would happen if a thin slice of sugar beet is placed in a concentrated solution of NaCI?
a) It should lose water from the cells
b) It should become turgid
c) It should neither absorb water not lose it
d) It should absorb water from the salt solution

36) Of the following answers, which correctly explains why plants die when overfertilized? The fertilizer
a) Damages the wall of the delicate root hairs
b) Blocks absorption of nitrogenous ions
c) Causes excessive growth
d) Upsets the soil environment by poisoning soil bacteria

37) Bacteria cannot survive in a highly salted pickle because
a) Salt inhibits reproduction of bacteria
b) Enough light is not available for photosynthesis
c) They become plasmolysed and die
d) Nutrients in the pickle medium can not support life

38) When pieces of potato tissue were placed in a solution, after some time, a loss in weight was recorded; the possible reason could be
a) Death of tissue
b) Exit of solutes
c) Exosmosis
d) Respiration of tissue

39) A cell placed in hypertonic solution plasmolyses; the space between the cell wall and plasmolysed contents is filled with
a) Water
b) Cell sap
c) Hypertonic solution
d) Hypotonic solution

40) Deplasmolysis in a cell occurs when plasmolysed cell is immersed in a
a) Hypotonic solution
b) Isotonic solution
c) Hypertonic solution
d) None of the above

41) The root cap has no role in water absorption because
a) It has no cells containing chloroplasts
b) It has no root hairs
c) It has no direct connection with the vascular system
d) It has loosely arranged cells

42) During the absorption of water by the roots, the water potential of cell sap is lower than that of
a) Pure water and the soil solution
b) Neither pure water, nor the soil solution
c) Pure water, but higher than that of the soil solution
d) The soil solution but higher than that of pure water

43) The movement of water of the cortex from one cell to the adjacent one in the roots is due to the
a) Accumulation of inorganic salts in the cells
b) Accumulation of organic compounds in the cells
c) Chemical potential gradient
d) Water potential gradient

44) Many transplanted seedlings do not survive because
a) The leaves get damaged during this process
b) Most of the root hairs are lost during transplantation
c) They do not like the new soil
d) They do not get the required minerals

45) Water will be absorbed by root hairs when the external medium is
a) Isotonic
b) Viscous
c) Hypotonic
d) Hypertonic

46) The loss of water in the form of vapour from aerial plant parts is known as
a) osmosis
b) Respiration
c) Photosynthesis
d) Transpiration

47) Transpiration occurs through the
a) Stomata
b) Cuticle
c) Lenticels
d) All the above

48) Maximum transpiration occurs through the
a) Aerial root
b) Stem
c) Leaf
d) Fruits

49) In mesophytes, maximum transpiration occurs from the
a) Cuticle
b) Lenticels
c) Stomata
d) Hydathodes

50) Wilting of plants results from an excessive
a) Absorption
b) Photosynthesis and poor osmosis
c) Respiration
d) Transpiration

51) Transpiration is regulated by
a) Guard cells
b) Subsidiary cells
c) Both
d) Cuticle and lenticel

52) Which of the following is produced during water stress and causes closure of stomata?
a) Cytokinin
b) Auxin
d) ABA

53) Which of the following walls of a guard cell are thick?
a) Outer
b) Inner
c) Side walls
d) All three

54) Transpiration is minimized by the deposition of
a) Cellulose
b) Cutin
c) Pectin
d) Mucilage

55) Stomata open during the day and close at night because
a) Photosynthesis occurs during day time only
b) The guard cells contain sugar at elevated pH in light
c) the loss of sugar increases the osmotic concentration of the cell sap
d) the loss of starch in the day time raises the OP of the subsidiary cells

56) In which of the following plants would transpiration be hindered if their leaves were coated with wax on their upper side?
a) Hydrilla
b) Vallisnaria
c) Nymphala
d) Pistia

57) The stomata will open, if there is an accumulation of the following
elements in the guard cells

a) Ca
b) Mg
c) Fe
d) K

58) Guard cells differ from epidermal cells in having
a) A nucleus
b) Mitochondria
c) Ribosomes
d) Chloroplasts

59) Which of the following changes in the cell sap of the guard cells occur
during the opening of stomata?

a) Decrease in osmotic pressure but increase in turgor pressure
b) Increase in osmotic pressure but decrease in turgor pressure
c) Increase of osmotic as well as turgor pressure
d) Decrease of osmotic as well as turgor pressure

60) Stomata in angiosperms open and close due to
a) Their genetic constitution
b) Effect of hormones
c) Changes of turgor pressure in guard cells
d) Pressure of gases inside the leaves

61) The metal ion involved in stomatal regulation is
a) Iron
b) Magnesium
c) Zinc
d) Potassium

62) In the mechanism of the opening of stomata, the important factor is the
a) Shape of the guard cells
b) Chlorophyll content of the cells
c) Hormone content of the cells
d) Protein content of the cells

63) Stomata open because of
a) Oxygen in the air
b) Increased turgidity of the guard cells brought about by exposure to light
c) Vacuoles in guard cells
d) All the above

64) Stomata open during the day because the guard cells have
a) Thin outer walls
b) a kidney shape
c) Chlorophyll
d) Large nuclei

65) Stomata open at night and close during the day time in
a) Succulents
b) Mesophytes
c) Hydrophytes
d) Xerophytes

66) In guard cells, when sugar is converted into starch, the stomatal pore
a) Opens fully
b) Opens partially
c) Closes completely
d) Remains uncharged

67) The basis of stomatal opening is
a) Exosmosis
b) Endosmosis
c) Decrease in cell sap concentration
d) Plasmolysis of guard cells

68) Which of the following is an effective adaptation for better gas exchange
in plants?

a) Presence of multiple epidermal layers
b) Presence of hair on the lower epidermis
c) Presence of a waxy cuticle covering the epidermis of the leaves
d) The location of stomata primarily on the lower surface of the leaf, the side turned away from the direct sun rays

69) Gaseous exchange in submerged hydrophytes takes place through the
a) Lenticels
b) Stomata
c) Water stomata
d) General epidermis

70) In a potometer, the twig absorbs water from the potometer
a) Actively
b) Passively
c) Partly by both means
d) None

71) If a planted potometer is kept under fan or bright light, the bubble of the potometer would
a) Move fast
b) Move slowly
c) Stop moving
d) Disappear

72) Wilting of a plant results from excessive
a) Absorption
b) Photosynthesis
c) Respiration
d) Transpiration

73) The loss of turgor of the cells causes drooping of leaves during the day,
but they recover from it at night. This is referred to as

a) Guttation
b) Permanent wilting
c) Temporary wilting
d) None of these

74) Which of the following factors is the most important in the regulation
of transpiration?

a) Humidity
b) Light
c) Temperature
d) Wind

75) Transpiration would be lowest when
a) Wind velocity is high
b) There is enough water in the soil
c) Atmospheric humidity is high
d) There is high temperature and bright light

76) Transpiration from plants will be more rapid when
a) the atmosphere is saturated with water
b) There is an excess of water in the cell
c) the air is still
d) The environment has a low saturation vapour pressure

77) The conditions under which transpiration would be most rapid is
a) Low velocity of wind
b) Low humidity and high temperature
c) High humidity
d) Excess water in the soil

78) With an increase in temperature, the rate of transpiration becomes
a) Low
b) High
c) Low in herbs and high in trees
d) Immediately nil

79) Under what conditions would transpiration be most rapid?
a) Excess of water in the soil
b) A low temperature and high humidity
c) Bright light and high
d) A high temperature and low relative humidity

80) Under which of the following conditions will the transpiration pull will be maximum?
a) Open stomata, a highly humid atmosphere and well irrigated soil
b) Open stomata, a dry atmosphere and moist soil
c) Open stomata, a highly humid atmosphere and dry soil
d) Closed stomata, low light intensity and a humid atmosphere

81) Some of the growth regulators affect stomatal opening. Closure of stomata
is brought about by

a) Indole butyric acid
b) Abscisic acid
c) Kinetin
d) Gibberellic acid

82) Which one of the following chemicals serves as an anti-transpirant in

a) Cobalt chloride
b) Mercury
c) Potassium
d) Phenyl mercuric acetate

83) The shade of a tree is cooler than the shade of a roof due to
a) Guttation
b) Green leaves
c) Transpiration
d) Photosynthesis

84) The spraying of phenyl mercuric acetate on leaves
a) Increases transpiration
b) Reduces transpiration
c) Increases rate of photosynthesis
d) Causes guttation

85) Exudation of water in the form of liquid from the margin of a leaf is
called (or the process of water exudation through hydathodes is called)

a) Evaporation
b) Osmosis
c) Transpiration
d) Guttation

86) Guttation is caused by
a) Transpiration
b) Osmosis/DPD
c) Root pressure
d) Osmotic pressure

87) Guttation is the eliminiation of excess of water from plants through the
a) Stomata
b) Hydathodes
c) Lenticels
d) Wounds

88) Guttation occurs only in
a) Mangroves
b) Mesophytic herbs
c) Marshy plants
d) Hydrophytes

89) Usually, guttation occurs in well-watered herbaceous plants in well-drained
soil only in the

a) Dry hours
b) Noon hours
c) Morning hours
d) Evening hours

90) Transpiration rate of a plant is not affected by the
a) Root-shoot ratio
b) Leaf area
c) Stomatal frequency
d) Leaf margin type

91) If abscissic acid is sprayed on leaves, the stomata will
a) Open
b) Close
c) Burst
d) No response

92) The difference between evaporation and transpiration is that
a) Transpiration is a physiological phenomenon and evaporation is a physical process
b) Evaporation is a physiological process whereas transpiration is a physical

c) Transpiration gives a cooling effect but evaporation does not
d) Transpiration is faster than evaporation

93) Lenticels and hydathodes are small pores with the following common attributes:
a) Their opening and closing is not regulated
b) They allow exchange of gases
c) They always remain closed
d) They are found on the same organ of plants

94) Photosynthesis is a process by which the plants prepare food material in the leaves. It can be described in the following way:CORRECT IMAGE

95) Nine-tenth of all the photosynthesis in the world is carried out by
a) Green ferns of the forests
b) Scientists in the laboratories
c) Algae of the oceans
d) Large trees with millions of branches and leaves

96) Photosynthesis is mainly responsible for the survival of
a) Animals on this earth
b) Plants on this earch
c) Both plants and animals
d) none of these

97) The aerobic atmosphere on earth is maintained by
a) Prokaryotes
b) Protists
c) Plants
d) Fungi

98) The bulk fixation of carbon through photosynthesis takes place in
a) Crop plants
b) Tropical rain forests and crop plants
c) Tropical rain forests
d) Oceans

99) The ultimate biological energy comes from
a) Mitochondria
b) Sunlight
c) Glucose
d) ATP

100) Light energy is changed into chemical energy during the process of
a) Transpiration
b) Photosynthesis
c) Degestion
d) Respiration



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