Plant and Water
Multiple Choice Questions and Answers
1. Cell membrane is
(a) permeable
(b) impermeable
(c) semi-permeable
(d) plasmodesmata
Answer: (c) semi-permeable
2. The process of taking gaseous carbon dioxide or oxygen by the leaves is termed
(a) exosmosis
(b) osmosis
(c) transpiration
(d) diffusion
Answer: (d) diffusion
3. If osmotic potential of a cell is -10 bars and its pressure potential is 5 bars, its water potential would be
(a) – 5 bars
(b) 5 bars
(c) -10 bars
(d) 10 bars
Answer: (a) – 5 bars
4. Diffusion pressure deficit may be defined as the amount by which the diffusion pressure of
(a) a solution is lower than that of its solvent
(b) a solution is higher than that of its solvent
(c) a solvent is higher than that of its solutes
(d) a solvent is lower than that of its solutes
Answer: (a) a solution is lower than that of its solvent
5. Purple cabbage leaves do not lose their colour in cold water but do so in boiling water because
(a) the plasma membrane gets killed in boiling water
(b) hot water can enter the cells quickly
(c) the pigment is not soluble in cold water
(d) the cell wall is killed in boiling water
Answer: (a) the plasma membrane gets killed in boiling water
6. When a cell is fully turgid which one of the following is zero?
(a) turgor pressure
(b) wall pressure
(c) diffusion pressure deficit
(d) osmotic pressure
Answer: (c) diffusion pressure deficit
7. If a piece of potato tuber is placed in concentrated sugar solution
(a) it would become limp due to loss of water from its cells
(b) it will come turgid by absorbing water from sugar solution
(c) the cells would show endosmosis
(d) it swells up due to imbibition
Answer: (a) it would become limp due to loss of water from its cells
8. A cell is placed in 0.5 M solution of sugar and no change in the volume or weight of the cell is observed. The concentration of the cell sap is
(a) 0.5 M
(b) 5.0 M
(c) 1.0 M
(d) 50.0M
Answer: (a) 0.5 M
9. When a cell is kept in 0.5 M solution of sucrose its volume does not alter. If the same cell is placed in 0.5 M solution of sodium chloride the volume of the cell
(a) will remain same
(b) will decrease
(c) will be plasmolysed
(d) will not show any change
Answer: (b) will decrease
10. If cell A with OP=5 and TP= 4 is surrounded by the cells with OP=3 and TP=1, what will be the direction of the water movement?
(a) From cell A to surrounding cells
(b) From surrounding cells to cell A
(c) Water will not move
(d) Water will move out
Answer: (a) From cell A to surrounding cells
11. Bacteria cannot survive in a highly salted pickle because
(a) salt inhibits reproduction
(b) bacteria do not get enough light for photosynthesis
(c) they become plasmolyzed and consequently killed
(d) the pickle does not contain nutrients necessary for bacteria to live
Answer: (c) they become plasmolyzed and consequently killed
12. When beetroot cylinders are washed and then placed in cold water none of the anthocyanins come out. This indicates most likely that plasma membrane is
(a) permeable to anthocyanins
(b) impermeable to anthocyanins
(c) differentially permeable to anthocyanins
(d) dead
Answer: (b) impermeable to anthocyanins
13. Seeds swell when placed in water because of
(a) osmosis
(b) imbibition
(c) hydrolysis
(d) none
Answer: (b) imbibition
14. Selective permeability identifies the process of
(a) diffusion
(b) osmosis
(c) imbibition
(d) plasmolysis
Answer: (b) osmosis
15. A cell when placed in solution get plasmolysed. What is largely present in between the cell wall and the plasmolysed contents?
(a) water
(b) cell sap
(c) hypotonic solution
(d) hypertonic solution
Answer: (d) hypertonic solution
16. The magnitude of diffusion pressure deficit in non turgid cell is equal to
(a) osmotic pressure-wall pressure
(b) osmotic pressure + wall pressure
(c) turgor pressure
(d) osmotic pressure
Answer: (a) osmotic pressure-wall pressure
17. The movement of water from one cell to the cortex of the adjacent one in the roots is due to
(a) accumulation of inorganic salts in the cells
(b) accumulation of organic compounds in the cell
(c) chemical potential gradient
(d) water potential gradient
Answer: (d) water potential gradient
18. In the process of plasmolysis occurs
(a) endosmosis
(b) exosmosis
(c) imbibition
(d) diffusion
Answer: (b) exosmosis
19. The term water potential was proposed by
(a) Lloyd
(b) Sayre
(c) Van Mohl
(d) Slatyor and Taylor
Answer: d) Slatyor and Taylor
20. Seed increases in volume by absorption of water through a phenomenon called
(a) imbibition
(b) transfusion
(c) osmosis
(d) diffusion
Answer: (a) imbibition
21. The water potential and osmotic potential of pure water are respectively
(a) 100 and zero
(b) zero and zero
(c) 100 and 100
(d) zero and 100
Answer: (b) zero and zero
22. If a cell A, D and D4 bar is connected to cells B,C,D whose OP and TP are respectively 4 and 4, 10 and 5 and, 7 and 3 bars, the flow of water will be
(a) C to A, B and D
(b) B to A, C and D
(c) A and D, B to C
(d) A to B, C and D
Answer: (b) B to A, C and D
23. Under given suitable conditions, the DPD will be more than OP when
(a) TP is negative
(b) OP is equal to TP
(c) OP is less than TP
(d) OP is greater than TP
Answer: (a) TP is negative
24. Selectively permeable membrane allows the passage of
(a) water only
(b) solvent only
(c) solute only
(d) selected solutes and solvents
Answer: (d) selected solutes and solvents
25. In turgid conditions of cell, its
(a) DPD=TP
(b) DPD=OP
(c) DPD=0
(d) OP=0
Answer: (b) DPD=OP
26. The water absorbing capacity of a solution is also known as
(a) DPD
(b) SP
(c) both a and b
(d) none of these
Answer: (c) both a and b
27. What is the effect of pressure on water potential?
(a) pressure decreases water potential
(b) pressure raises water potential
(c) pressure does not affect water potential
(d) pressure exerts same effect as addition of solutes
Answer: (b) pressure raises water potential
28. When a cell is placed in hypotonic solution
(a) solute comes out of the cell to equalize the concentration on both sides of the membrane
(b) water enters the cell towards the area of lower solute concentration
(c) water enters the cell (towards the area of higher solute concentration)
(d) solute comes out of the cell and water enters the cells
Answer: (c) water enters the cell (towards the area of higher solute concentration)
29. If potato slices are placed in sucrose solution, after an hour the sucrose solution becomes sweeter than it was before the slices were put in it. Water potential of potato tubers is
(a) greater than that of sucrose solution
(b) equal to that of sucrose solution
(c) less than that of sucrose solution
(d) equal to the osmotic pressure of sucrose solution
Answer: (c) less than that of sucrose solution
30. When a cell is slightly plasmolysed, which of the following conclusions may be correct?
(a) OP=DPD
(b) OP>DPD
(c) OP=TP
(d) OP<DPD
Answer: (d) OP<DPD
31. The osmotic potential is denoted by a
(a) negative sign
(b) positive sign
(c) division sign
(d) astrix sign
Answer: (a) negative sign
32. The free energy per mole of any substance in a chemical system is known as
(a) osmotic potential
(b) water potential
(c) chemical potential
(d) potential gradient
Answer: (c) chemical potential
33. If a plant cell is immersed in water, the water continues to enter the cell until the
(a) concentration of the salt becomes equal both inside and outside the cell
(b) cell bursts
(c) diffusion pressure is the same inside and outside the cell
(d) permeability is affected
Answer: (c) diffusion pressure is the same inside and outside the cell
34. Osmosis, in your opinion, is a
(a) physical process
(b) chemical process
(c) biochemical process
(d) all the above
Answer: (a) physical process
35. The semipermeable membrane in the plant cell allows the diffusion of
(a) solvent molecules
(b) solute molecules
(c) both solvent and solute molecules
(d) none of the above
Answer: (a) solvent molecules
36. Which of the following statements is true for osmosis?
(a) diffusion of suspended particles from higher concentration to lower concentration
(b) movement of suspended molecules from lower concentration to higher concentration
(c) diffusion of solvent molecules from their higher concentration to lower concentration
(d) movement of solvent molecules from their higher to lower concentration through a semipermeable membrane
Answer: (d) movement of solvent molecules from their higher to lower concentration through a semipermeable membrane
37. A cell A (whose OP = 5 and TP = 4) is surrounded by a few adjoining cells (whose OP = 3 and TP = 1). What will be the direction of movement of water in this group of cells?
(a) from a drawing cells to cell A
(b) from cell A to adjoining cells
(c) water will not move at all
(d) water can move in any direction
Answer: (b) from cell A to adjoining cells
38. If a marine plant is placed in fresh water, then its
(a) cells will burst
(b) cells will shrink
(c) cell will show no effect
(d) entire plant will show wilting
Answer: (a) cells will burst
39. Due to plasmolysis, plant cell
(a) swells up
(b) cell becomes turgid
(c) becomes flaccid
(d) bursts
Answer: (c) becomes flaccid
40. In a fully turgid cell, what is equal to zero?
(a) TP
(b) OP
(c) WP
(d) DPD
Answer: (d) DPD
41. When water moves through a semipermeable membrane then which of the following pressure develops?
(a) OP
(b) SP
(c) TP
(d) WP
Answer: (a) OP
42. Which is incorrect?
(a) rate of diffusion is directly proportional to concentration
(b) rate of diffusion is inversely proportional to distance
(c) diffusion is movement of particles from low to high electrochemical potential
(d) example of diffusion is opening of scent or ammonia in one corner
Answer: (c) diffusion is movement of particles from low to high electrochemical potential
43. Plasmolysis occurs when cells are kept in
(a) hypotonic solution
(b) hypertonic solution
(c) isotonic solution
(d) none of the above
Answer: (b) hypertonic solution
44. What happens when concentration of solutes decreases in guard cells
(a) water potential decreases
(b) water potential increases
(c) osmotic pressure increases
(d) none of the above
Answer: (b) water potential increases
45. Solute potential of a solution is always
(a) =0
(b) <0
(c) >0
(d) Between 0.1-1.0
Answer: (b) <0
46. In a fully turgid cell the ……… is zero
(a) DPD
(b) OP
(c) WP
(d) TP
Answer: (a) DPD
47. Gases like carbon dioxide and oxygen enter into the leaves by the process known as
(a) osmosis
(b) diffusion
(c) plasmolysis
(d) transpiration
Answer: (b) diffusion
48. If living cell is placed in …… solution water enters into the cell by osmosis
(a) isotonic
(b) hypertonic
(c) hypotonic
(d) highly saline
Answer: (c) hypotonic
49. In rainy season, wooden door swells up due to
(a) imbibition
(b) capillarity
(c) endosmosis
(d) exosmosis
Answer: (a) imbibition
50. Root hairs absorb water from soil through
(a) turgor pressure
(b) ion exchange
(c) osmosis
(d) DPD
Answer: (c) osmosis