Multiple choice Questions of Botany Topic Nutrition in Plants MCQs with Answers and Plant-Water Relation & Transpiration MCQs ( Nutrition in Plants MCQs with Answers and Plant-Water Relation & Transpiration Quiz ) for NEET, GATE, AIAPGET, NEET MDS, NEET PG, DNB PDCET, AIIMS SS, PGIMER (Other), AIIMS PG and many more competitive examinations.
Plant water relations pdf | Plant water relations lecture notes pdf
1. Process of selective transmission of a liquid through semipermeable membrane is called
(a) diffusion
(b) osmosis
(c) plasmolysis
(d) transmission
Ans. b
2. When a cell is fully turgid which of the following will be zero?
(a) Wall pressure
(b) Osmotic pressure
(c) Turgor pressure
(d) Water potential
Ans. d
3. Selective permeability identifies the phenomenon of
(a) imbibition
(b) osmosis
(c) diffusion
(d) plasmolysis
Ans. b
4. Change in diffusion pressure of a pure solvent, when it is added with a solute, is called
(a) osmosis
(b) diffusion
(c) DPD
(d) imbibition
Ans. c
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
Ans. b
6. With the increase in a turgidity of a cell, the wall pressu will
(a) increase
(b) decrease
(c) fluctuates
(d) remain unchanged
Ans. a
7. If a cell kept in a solution of unknown concentration gets deplasmolysed, then the solution is called
(a) hypotonic
(b) hypertonic
(c) isotonic
(d) detonic
Ans. a
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8. DPD is equal to
(a) OP – WP
(b) OP + WP
(c) TP
(d) OP
Ans. a
9. Water potential in the leaf tissue is positive (+) during
(a) excessive transpiration
(b) low transpiration
(c) excessive absorption
(d) guttation
Ans. c
10. In a flaccid cell
(a) TP = OP
(b) DPD = TP
(c) OP = O
(d) DPD = OP
Ans. d
11. If turgor pressure becomes equal to the wall pressure then
(a) water leaves the cell
(b) no exchange of water takes place
(c) water enters the cell
(d) solute goes from the cell into water
Ans. b
12. Osmotic pressure is responsible for the turgidity of plant cells which
(a) causes cell elongation
(b) causes opening of stomata
(c) prevents wilting of leaves
(d) All of the above
Ans. d
13. Root pressure can be measured by means of
(a) porometer
(b) potometer
(c) auxanometer
(d) manometer
Ans. d
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14. DPD stands for
(a) Diffusion Pressure Deficit
(b) Diffusion Pressure Demand
(c) Daily Photosynthetic Depression
(d) Daily Phosphorus Demand
Ans. a
15. A cell becomes turgid, when placed in
(a) isotonic solution
(b) hypertonic solution
(c) hypotonic solution
(d) None of these
Ans. c
16. Osmosis is
(a) diffusion of solvent
(b) diffusion of solute
(c) imbibition of solution
(d) None of these
Ans. a
17. Which of the following do not transpire?
(a) Aigae
(b) Fungi
(c) Submerged hydrophytes
(d) All of these
Ans. d
18. The diameter of stomatal pore ranges between
(a) 25-50 µ
(b) 15-25 µ
(c) 3-10 µ
(d) 1-2 µ
Ans. b
19. The rate of transpiration is affected by
(a) root-shoot ratio
(b) leaf area
(c) shape of leaf margin
(d) Both (a) and (b)
Ans. d
20. The rate of transpiration increases with the decrease of
(a) temperature
(b) moderate wind
(c) light
(d) atmospheric pressure
Ans. d
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21. Absorption of water by roots is increased when
(a) transpiration rate is less
(b) salt absorption is increased
(c) trarispiration rate increases
(d) photosynthetic rate increases
Ans. c
22. When stomata open in night only, they are called
(a) photoactive stomata
(b) scotoactive stomata
(c) nyctinastic stomata
(d) All of these
Ans. b
23. Such a membrane, which permits only the selected materials to pass through it termed as
(a) permeable
(b) impermeable
(c) semipermeable
(d) selectively semipermeable
Ans. d
24. Swelling of grapes in water confirms to
(a) exosmosis
(b) endosmosis
(c) diffusion
(d) imbibition
Ans. b
25. In a fully turgid cell, the values (arbitrary values are shown) of DPD, OP and TP will show the tendency as
(a) DPD 10 atm: OP 15 atm; TP 5 atm
(b) DPD 02 atm, OP 07 atm, TP 5 atm
(c) DPD 05 atm; OP 12 atm; TP 7 atm
(d) DPD 00 atm; OP 15 atm; TP 15 atm
Ans. d
26. The real force responsible for the movement of water form one cell to other cell is mainly
(a) OP
(b) TP
(c) DPD
(d) Imbibition
Ans. c
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27. Under which condition, does DPD becomes more than OP?
(a) OP < TP
(b) OP = TP
(c) TP is – ve
(d) OP > TP
Ans. c
28. When a plasmolysed cell is placed in hypotonic solution then water enter in cell due to which force
(a) DPD
(b) OP
(c) WP
(d) None of these
Ans. a
29. When roots are kept in a hypotonic solution, the process of root pressure will
(a) not be affected
(b) increase
(c) decrease
(d) stop
Ans. d
30. In a plasmolysed cell, the space between cell wall and plasma membrane is occupied by
(a) external solution
(b) water from cell sap
(c) Both (a) and (b)
(d) None of these
Ans. b
31. Water potential in the leaf tissue is positive (+) during
(a) excessive transpiration
(b) low transpiration
(b) excessive absorption
(d) guttation
Ans. b
32. Selective permeability identifies the phenomenon of
(a) imbibition
(b) osmosis
(c) diffusion
(d) plasmolysis
Ans. b
33. When stomata remain open throughout the day and night, they are called
(a) alfa-alfa type
(b) potato type
(c) barley type
(d) Equisetum type
Ans. d
34. Transpiration is regulated by
(a) guard cells
(b) subsidiary cells
(c) Both (a) and (b)
(d) cuticie and lenticel
Ans. a
35. Swelling of grapes in water confirms to
(a) exosmosis
(b) endosmosis
(c) imbibition
(d) diffusion
Ans. b
36. In a flaccid cell
(a) DPD = PO
(b) DPD = TP
(c) TP = OP
(d) OP = O
Ans. a
37. A cell kept in hypertonic solution then cell will be
(a) turgid
(b) flaccid
(c) plasmolysed
(d) impermeable
Ans. c
38. By which greek letter the osmotic pressure is indicated
(a) Y
(b) n
(c) 8
(d) A
Ans. a
39. If the cell wall is elastic instead of being rigid and if the cell is put in a medium of sugar solution of higher concentration that in the cell then
(a) the cytoplasm will be pulled away from the wall as water moves out
(b) cell shape and size will not change
(c) the wall will shrink along with the cytoplasm
(d) the cell wall will rupture as the cytoplasm shrinks
Ans. c
40. Initial absorption of water by root hair is through
(a) osmosis
(b) endosmosis
(c) absorption
(d) imbibition
Ans. d
Chapter Wise MCQs are mention below.
- Water Potential
- Osmosis
- Plasmolysis
- Imbibition
- Absorption of Water by Plants
- Mechanism of Water Absorption
Water Potential MCQs
Question 1: What is water potential?
a) The potential energy of water molecules
b) The concentration of dissolved solutes in water
c) The pressure exerted by water against a container
d) The amount of water present in a system
Answer: a) The potential energy of water molecules
Explanation: Water potential is a measure of the potential energy possessed by water molecules in a system. It accounts for factors like solute concentration and pressure, determining the direction and rate of water movement.
Question 2: Which factor contributes to a decrease in water potential?
a) High solute concentration
b) High hydrostatic pressure
c) High turgor pressure
d) High atmospheric pressure
Answer: a) High solute concentration
Explanation: High solute concentration lowers the water potential, making the water potential of a solution more negative compared to pure water. Water moves from regions of higher water potential to lower water potential.
Question 3: What is the water potential of pure water under standard conditions?
a) 0 MPa
b) -1 MPa
c) -0.23 MPa
d) -10 MPa
Answer: a) 0 MPa
Explanation: The water potential of pure water under standard conditions is defined as 0 MPa. This is used as a reference point for measuring water potential in other solutions.
Question 4: Which component of water potential represents the pressure exerted on cell walls by the contents of a plant cell?
a) Matric potential
b) Osmotic potential
c) Pressure potential
d) Gravitational potential
Answer: c) Pressure potential
Explanation: Pressure potential is the component of water potential that represents the pressure exerted on cell walls due to the turgor pressure of the cell contents. It can be positive or negative depending on the direction of pressure.
Question 5: What is the mathematical relationship between solute potential (Ψs) and water potential (Ψ)?
a) Ψ = Ψs
b) Ψ = Ψs + Ψp
c) Ψ = Ψs – Ψp
d) Ψ = Ψs * Ψp
Answer: c) Ψ = Ψs – Ψp
Explanation: Water potential (Ψ) is the sum of solute potential (Ψs) and pressure potential (Ψp). The equation is: Ψ = Ψs + Ψp. Since pressure potential can be positive or negative, the equation is often written as Ψ = Ψs – Ψp.
Question 6: How does adding solutes to a solution affect its water potential?
a) Increases water potential
b) Has no effect on water potential
c) Decreases water potential
d) Converts water potential to pressure potential
Answer: c) Decreases water potential
Explanation: Adding solutes to a solution decreases its water potential. As solute concentration increases, water potential becomes more negative, leading to water movement from regions of higher water potential to lower water potential.
Question 7: What is the water potential of a solution in an open container?
a) Equal to atmospheric pressure
b) Equal to gravitational potential
c) Equal to turgor pressure
d) Equal to zero
Answer: a) Equal to atmospheric pressure
Explanation: In an open container, the pressure potential (Ψp) is zero, and the water potential (Ψ) is determined by the solute potential (Ψs). It’s equal to atmospheric pressure, which is often considered as zero potential.
Question 8: Which of the following factors would result in the most negative water potential?
a) Low solute concentration
b) Low pressure potential
c) High turgor pressure
d) High atmospheric pressure
Answer: b) Low pressure potential
Explanation: The pressure potential component of water potential can be negative if the pressure is low or if the system is under tension. The more negative the pressure potential, the more negative the overall water potential becomes.
Question 9: What is the significance of water potential in plant biology?
a) It determines the color of plant leaves
b) It affects the size of plant cells
c) It regulates the opening and closing of stomata
d) It controls the rate of photosynthesis
Answer: c) It regulates the opening and closing of stomata
Explanation: Water potential plays a crucial role in regulating the opening and closing of stomata, which in turn affects gas exchange, transpiration, and water loss in plants.
Question 10: Which type of water potential component is responsible for the uptake of water by roots from the soil?
a) Solute potential
b) Pressure potential
c) Gravitational potential
d) Matric potential
Answer: d) Matric potential
Explanation: Matric potential, a type of pressure potential, accounts for the attraction of water to soil particles and is responsible for water uptake by plant roots from the soil.
Question 11: Which of the following units is commonly used to express water potential?
a) Millimeters
b) Molarity
c) Megapascals (MPa)
d) Milliliters
Answer: c) Megapascals (MPa)
Explanation: Water potential is often measured in units of pressure, and Megapascals (MPa) is a common unit used for this purpose.
Question 12: What happens to water potential as you move from the soil to the leaves of a plant?
a) It remains constant
b) It increases
c) It decreases
d) It becomes negative
Answer: c) It decreases
Explanation: Water potential generally decreases as you move from the soil (higher potential) to the leaves (lower potential) due to various factors affecting water movement.
Question 13: Which component of water potential accounts for the cohesive properties of water molecules?
a) Solute potential
b) Pressure potential
c) Matric potential
d) Gravitational potential
Answer: b) Pressure potential
Explanation: Pressure potential accounts for the cohesive properties of water molecules and their ability to be pulled upward in plants.
Question 14: What does a water potential of -1.5 MPa indicate?
a) A very high water potential
b) A slightly negative water potential
c) A very low water potential
d) A positive water potential
Answer: c) A very low water potential
Explanation: A water potential of -1.5 MPa indicates a very low water potential, meaning that the water potential of the solution is more negative compared to pure water.
Question 15: What role does aquaporin play in water movement within plant cells?
a) Increases solute potential
b) Decreases turgor pressure
c) Facilitates osmosis and water movement
d) Reduces pressure potential
Answer: c) Facilitates osmosis and water movement
Explanation: Aquaporins are membrane proteins that facilitate the movement of water molecules across cell membranes, promoting osmosis and water movement within plant cells.
Question 16: How does an increase in turgor pressure affect water potential?
a) Increases water potential
b) Decreases water potential
c) Has no effect on water potential
d) Converts water potential to pressure potential
Answer: a) Increases water potential
Explanation: Turgor pressure (pressure potential) contributes positively to the overall water potential, so an increase in turgor pressure leads to an increase in water potential.
Question 17: Under what conditions is the water potential of a plant cell at its highest?
a) When the cell is fully turgid
b) When the cell is flaccid
c) When the cell is plasmolyzed
d) When the cell is in equilibrium
Answer: c) When the cell is plasmolyzed
Explanation: The water potential of a plant cell is at its highest when the cell is fully plasmolyzed (shrunk due to water loss), as the pressure potential is essentially zero.
Question 18: How does the water potential of a solution change when it is heated?
a) Increases
b) Decreases
c) Remains constant
d) Becomes negative
Answer: b) Decreases
Explanation: Heating a solution increases its kinetic energy, causing water molecules to move faster and increasing vapor pressure, which in turn decreases the water potential of the solution.
Question 19: Which type of water potential component accounts for the adhesion of water to surfaces within plant cells?
a) Solute potential
b) Pressure potential
c) Matric potential
d) Gravitational potential
Answer: c) Matric potential
Explanation: Matric potential accounts for the adhesion of water to surfaces within plant cells, like cell walls and membranes.
Question 20: How does the water potential of a solution in a closed container compare to atmospheric pressure?
a) It is always higher than atmospheric pressure
b) It is always lower than atmospheric pressure
c) It is equal to atmospheric pressure
d) It depends on the solute concentration
Answer: c) It is equal to atmospheric pressure
Explanation: In a closed container, pressure potential (Ψp) is zero, and water potential (Ψ) is determined solely by solute potential (Ψs), which equals atmospheric pressure.
Question 1: What is osmosis?
Osmosis MCQs
a) The movement of solute molecules from a region of lower concentration to higher concentration.
b) The movement of water molecules from a region of higher concentration to lower concentration.
c) The movement of water molecules from a region of lower concentration to higher concentration.
d) The movement of gas molecules across a semi-permeable membrane.
Answer: c) The movement of water molecules from a region of lower concentration to higher concentration.
Explanation: Osmosis is the movement of water molecules across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Question 2: What is a semi-permeable membrane?
a) A membrane that allows all substances to pass through.
b) A membrane that only allows water to pass through.
c) A membrane that only allows solute molecules to pass through.
d) A membrane that allows certain substances to pass through while restricting others.
Answer: d) A membrane that allows certain substances to pass through while restricting others.
Explanation: A semi-permeable membrane allows certain molecules or ions to pass through while restricting the passage of others based on size, charge, or other properties.
Question 3: In which direction does water move in osmosis?
a) From a region of higher solute concentration to lower solute concentration.
b) From a region of lower solute concentration to higher solute concentration.
c) Equally in both directions.
d) It doesn’t move in osmosis.
Answer: b) From a region of lower solute concentration to higher solute concentration.
Explanation: Water moves through osmosis from an area of lower solute concentration (higher water potential) to an area of higher solute concentration (lower water potential).
Question 4: What is meant by a hypertonic solution?
a) A solution with a high concentration of solute compared to another solution.
b) A solution with a low concentration of solute compared to another solution.
c) A solution that is isotonic to another solution.
d) A solution that does not contain solute.
Answer: a) A solution with a high concentration of solute compared to another solution.
Explanation: A hypertonic solution has a higher solute concentration than another solution, causing water to move out of cells by osmosis.
Question 5: What happens to a red blood cell when placed in a hypotonic solution?
a) It shrinks.
b) It stays the same.
c) It swells and may burst.
d) It undergoes no change.
Answer: c) It swells and may burst.
Explanation: In a hypotonic solution, where the solute concentration outside the cell is lower, water moves into the cell, causing it to swell and potentially burst (lysis).
Question 6: What prevents plant cells from bursting in a hypotonic environment?
a) The rigid cell wall.
b) The flexible plasma membrane.
c) The presence of aquaporins.
d) The active transport of solutes.
Answer: a) The rigid cell wall.
Explanation: The rigid cell wall of plant cells prevents them from bursting in a hypotonic environment by exerting pressure against the influx of water.
Question 7: What is an isotonic solution?
a) A solution with a high concentration of solute compared to another solution.
b) A solution with a low concentration of solute compared to another solution.
c) A solution that is equal in solute concentration to another solution.
d) A solution that does not contain solute.
Answer: c) A solution that is equal in solute concentration to another solution.
Explanation: An isotonic solution has the same solute concentration as another solution, resulting in no net movement of water across the membrane.
Question 8: What is turgor pressure in plant cells?
a) The pressure exerted by the cell wall on the plasma membrane.
b) The pressure exerted by the cell’s contents against the cell wall.
c) The pressure of external forces on the cell membrane.
d) The pressure of solutes outside the cell.
Answer: b) The pressure exerted by the cell’s contents against the cell wall.
Explanation: Turgor pressure is the pressure exerted by the cell’s contents against the cell wall due to water entering the cell through osmosis.
Question 9: What term describes a solution that has the same solute concentration as another solution?
a) Hypotonic
b) Hypertonic
c) Isotonic
d) Osmotic
Answer: c) Isotonic
Explanation: An isotonic solution has the same solute concentration as another solution, resulting in no net movement of water between them.
Question 10: What is meant by plasmolysis?
a) The bursting of cells due to excess water intake.
b) The shrinkage of cells due to water loss.
c) The movement of water into cells.
d) The movement of solutes out of cells.
Answer: b) The shrinkage of cells due to water loss.
Explanation: Plasmolysis occurs when a plant cell loses water and its contents shrink away from the rigid cell wall.
Question 11: What is a selectively permeable membrane?
a) A membrane that allows only water molecules to pass through.
b) A membrane that allows all substances to pass through freely.
c) A membrane that allows only certain molecules to pass through while restricting others.
d) A membrane that allows gases to pass through but not liquids.
Answer: c) A membrane that allows only certain molecules to pass through while restricting others.
Explanation: A selectively permeable membrane allows only specific molecules to pass through, based on their size, charge, and other properties.
Question 12: What is meant by the term “osmotic pressure”?
a) The pressure applied to prevent osmosis from occurring.
b) The pressure created by the movement of water molecules.
c) The pressure exerted by solute molecules in a solution.
d) The pressure exerted by solute molecules to resist osmotic movement.
Answer: c) The pressure exerted by solute molecules in a solution.
Explanation: Osmotic pressure is the pressure created by the movement of water molecules across a semipermeable membrane due to differences in solute concentration.
Question 13: What is a “hypertonic solution” in terms of cell biology?
a) A solution with a lower concentration of solute compared to another solution.
b) A solution with a higher concentration of solute compared to another solution.
c) A solution with equal solute concentration to another solution.
d) A solution with no solute concentration.
Answer: b) A solution with a higher concentration of solute compared to another solution.
Explanation: A hypertonic solution has a higher solute concentration than another solution, causing water to move out of cells by osmosis.
Question 14: Which direction does water move in a hypotonic solution?
a) From a region of lower solute concentration to higher solute concentration.
b) From a region of higher solute concentration to lower solute concentration.
c) Equally in both directions.
d) It doesn’t move in a hypotonic solution.
Answer: b) From a region of higher solute concentration to lower solute concentration.
Explanation: In a hypotonic solution, where the solute concentration is lower, water moves into cells by osmosis.
Question 15: What happens to plant cells in a hypertonic solution?
a) They swell and may burst.
b) They shrink and may undergo plasmolysis.
c) They remain unchanged.
d) They become more rigid.
Answer: b) They shrink and may undergo plasmolysis.
Explanation: In a hypertonic solution, water moves out of plant cells, causing them to shrink and potentially undergo plasmolysis.
Question 16: What is the term for the point at which water movement due to osmosis is balanced and there is no net movement of water?
a) Osmotic equilibrium
b) Hypotonic equilibrium
c) Isotonic equilibrium
d) Plasmolytic equilibrium
Answer: a) Osmotic equilibrium
Explanation: Osmotic equilibrium is the point where the movement of water due to osmosis is equal in both directions, resulting in no net movement of water.
Question 17: What type of transport is osmosis?
a) Passive transport
b) Active transport
c) Facilitated transport
d) Bulk transport
Answer: a) Passive transport
Explanation: Osmosis is a type of passive transport where water molecules move across a membrane without the need for energy input.
Question 18: How is reverse osmosis used in water treatment?
a) To remove large particles from water.
b) To add minerals to water.
c) To transport water against its concentration gradient.
d) To remove impurities and contaminants from water.
Answer: d) To remove impurities and contaminants from water.
Explanation: Reverse osmosis is a process used to purify water by forcing it through a semipermeable membrane to remove impurities, minerals, and contaminants.
Question 19: What term is used to describe a solution that has a lower solute concentration compared to another solution?
a) Hypotonic
b) Hypertonic
c) Isotonic
d) Osmotic
Answer: a) Hypotonic
Explanation: A hypotonic solution has a lower solute concentration than another solution, causing water to move into cells by osmosis
Question 20: How does osmosis contribute to plant cell enlargement?
a) By pushing water out of cells.
b) By causing cells to shrink.
c) By facilitating the movement of solutes into cells.
d) By causing water to enter cells and increase turgor pressure.
Answer: d) By causing water to enter cells and increase turgor pressure.
Explanation: Osmosis causes water to enter plant cells, leading to an increase in turgor pressure and cell enlargement.
Plasmolysis MCQs
Question 1: What is plasmolysis?
a) The bursting of cells due to excess water intake.
b) The shrinkage of cells due to water loss.
c) The movement of water into cells.
d) The movement of solutes out of cells.
Answer: b) The shrinkage of cells due to water loss.
Explanation: Plasmolysis occurs when cells lose water and the contents of the cell shrink away from the cell wall.
Question 2: Which type of solution is likely to cause plasmolysis in plant cells?
a) Hypertonic solution
b) Hypotonic solution
c) Isotonic solution
d) Osmotic solution
Answer: a) Hypertonic solution
Explanation: Plasmolysis occurs in a hypertonic solution where the concentration of solutes outside the cell is higher than inside, causing water to move out of the cell.
Question 3: What is the primary cause of plasmolysis in plant cells?
a) Movement of solutes into the cell
b) Movement of water out of the cell
c) Movement of gases into the cell
d) Movement of water into the cell
Answer: b) Movement of water out of the cell
Explanation: Plasmolysis occurs when water moves out of plant cells, causing the cytoplasm to shrink away from the cell wall.
Question 4: Which plant structure prevents plasmolysis from occurring in a hypotonic environment?
a) Cell membrane
b) Cell wall
c) Chloroplast
d) Mitochondria
Answer: b) Cell wall
Explanation: The rigid cell wall of plant cells prevents them from undergoing plasmolysis in a hypotonic environment by exerting pressure against the shrinking of the cytoplasm.
Question 5: What happens to the turgor pressure of a plasmolyzed cell?
a) It increases
b) It decreases
c) It remains unchanged
d) It becomes negative
Answer: d) It becomes negative
Explanation: In plasmolysis, the cell loses water, and the cytoplasm shrinks away from the cell wall, leading to a negative turgor pressure.
Question 6: In which part of the plant cell does plasmolysis occur?
a) Nucleus
b) Vacuole
c) Cytoplasm
d) Cell wall
Answer: c) Cytoplasm
Explanation: Plasmolysis involves the shrinking of the cytoplasm away from the cell wall due to water loss.
Question 7: What is the primary factor that determines whether plasmolysis will occur in a cell?
a) Temperature
b) Cell size
c) Solute concentration
d) Cell shape
Answer: c) Solute concentration
Explanation: Plasmolysis occurs when the external solute concentration is higher than the internal concentration, leading to water loss from the cell.
Question 8: Which term describes the point at which a plasmolyzed cell becomes turgid again?
a) Plasmolysis point
b) Turgor recovery
c) Rehydration
d) Desiccation
Answer: c) Rehydration
Explanation: Rehydration is the process of adding water to a plasmolyzed cell, causing it to regain turgor pressure and return to its normal state.
Question 9: What term is used to describe a solution that causes plasmolysis in plant cells?
a) Hypertonic solution
b) Hypotonic solution
c) Isotonic solution
d) Osmotic solution
Answer: a) Hypertonic solution
Explanation: Plasmolysis occurs in a hypertonic solution, where the solute concentration outside the cell is higher than inside.
Question 10: What is the relationship between plasmolysis and water potential?
a) Plasmolysis increases water potential.
b) Plasmolysis has no effect on water potential.
c) Plasmolysis decreases water potential.
d) Plasmolysis converts water potential to pressure potential.
Answer: c) Plasmolysis decreases water potential.
Explanation: Plasmolysis causes water to leave the cell, leading to a decrease in water potential.
Question 11: Which organelle is often affected by plasmolysis?
a) Nucleus
b) Mitochondria
c) Vacuole
d) Ribosomes
Answer: c) Vacuole
Explanation: The vacuole, which stores water and solutes, is often affected during plasmolysis due to water loss.
Question 12: What is the primary function of the cell wall during plasmolysis?
a) To prevent water from entering the cell
b) To prevent water from leaving the cell
c) To prevent the cell from bursting
d) To transport solutes across the membrane
Answer: b) To prevent water from leaving the cell
Explanation: The rigid cell wall prevents water from leaving the cell and undergoing plasmolysis in a hypotonic environment.
Question 13: How does a hypertonic solution cause plasmolysis?
a) It causes water to enter the cell.
b) It causes the cell to burst.
c) It causes water to leave the cell.
d) It causes the cell to expand.
Answer: c) It causes water to leave the cell.
Explanation: In a hypertonic solution, water moves out of the cell, causing the cytoplasm to shrink and leading to plasmolysis.
Question 14: Which plant cell component does not undergo plasmolysis?
a) Cytoplasm
b) Vacuole
c) Cell wall
d) Cell membrane
Answer: c) Cell wall
Explanation: The cell wall does not undergo plasmolysis because it remains rigid even when the cell undergoes water loss.
Question 15: What effect does plasmolysis have on the shape of a plant cell?
a) The cell becomes spherical.
b) The cell becomes elongated.
c) The cell retains its original shape.
d) The cell collapses.
Answer: d) The cell collapses.
Explanation: Plasmolysis causes the cytoplasm to shrink away from the cell wall, resulting in the collapse of the cell’s structure.
Question 16: What is the term for the point at which a cell is about to undergo plasmolysis?
a) Turgor point
b) Osmotic point
c) Plasmolytic point
d) Incipient plasmolysis
Answer: d) Incipient plasmolysis
Explanation: Incipient plasmolysis refers to the point where a cell is on the verge of undergoing plasmolysis due to water loss.
Question 17: How can plasmolysis be reversed?
a) By increasing the external solute concentration.
b) By decreasing the external solute concentration.
c) By increasing the turgor pressure.
d) By removing the cell wall.
Answer: b) By decreasing the external solute concentration.
Explanation: Plasmolysis can be reversed by placing the plasmolyzed cell in a hypotonic solution with a lower solute concentration.
Question 18: What happens to the cell membrane during plasmolysis?
a) It expands.
b) It contracts.
c) It remains unchanged.
d) It becomes more permeable.
Answer: b) It contracts.
Explanation: During plasmolysis, the cell membrane contracts as the cytoplasm shrinks away from it due to water loss.
Question 19: Which of the following is not a consequence of plasmolysis in plant cells?
a) Cell bursting
b) Cell wilting
c) Loss of turgor pressure
d) Reduced metabolic activity
Answer: a) Cell bursting
Explanation: Plasmolysis does not lead to cell bursting; instead, it involves the shrinking of the cytoplasm.
Question 20: What is the importance of studying plasmolysis?
a) It helps understand the structure of the nucleus.
b) It provides insights into cell division.
c) It is useful for studying energy production in cells.
d) It aids in understanding water movement and cell health.
Answer: d) It aids in understanding water movement and cell health.
Explanation: Studying plasmolysis helps researchers understand how water movement affects cell health and provides insights into osmotic regulation in plant cells.
Imbibition MCQs
Question 1: What is imbibition?
a) The movement of water through plant roots.
b) The movement of solutes within a plant cell.
c) The swelling and uptake of water by dry materials.
d) The transfer of nutrients from the soil to the plant.
Answer: c) The swelling and uptake of water by dry materials.
Explanation: Imbibition is the process in which dry materials, such as seeds or plant tissues, absorb water and swell.
Question 2: What type of materials can undergo imbibition?
a) Only living cells
b) Only non-living materials
c) Both living cells and non-living materials
d) Only liquid materials
Answer: c) Both living cells and non-living materials
Explanation: Imbibition can occur in both living cells, such as plant tissues, and non-living materials like porous substances.
Question 3: What force drives imbibition?
a) Osmotic pressure
b) Gravity
c) Electromagnetic force
d) Capillary action
Answer: a) Osmotic pressure
Explanation: Imbibition is driven by the osmotic pressure generated as water is absorbed by the dry material, causing it to swell.
Question 4: Which type of substances show the highest imbibition capacity?
a) Hydrophobic substances
b) Non-porous substances
c) Hydrophilic and porous substances
d) Gaseous substances
Answer: c) Hydrophilic and porous substances
Explanation: Hydrophilic (water-attracting) and porous substances, such as cellulose or gelatin, have a high imbibition capacity due to their ability to absorb and retain water.
Question 5: What happens to the volume of a substance during imbibition?
a) It decreases
b) It remains unchanged
c) It becomes spherical
d) It increases
Answer: d) It increases
Explanation: During imbibition, the absorbed water causes the substance to swell and increase in volume.
Question 6: What role does capillarity play in imbibition?
a) Capillarity opposes imbibition.
b) Capillarity drives imbibition by drawing water in.
c) Capillarity prevents the uptake of water.
d) Capillarity only affects living cells during imbibition.
Answer: b) Capillarity drives imbibition by drawing water in.
Explanation: Capillarity, which is the ability of water to rise in narrow spaces due to adhesion and cohesion, helps draw water into porous materials during imbibition.
Question 7: Which of the following is a practical application of imbibition?
a) Water transportation in plants
b) Animal cell division
c) Seed germination
d) Blood circulation in humans
Answer: c) Seed germination
Explanation: Imbibition is essential for the process of seed germination, where dry seeds absorb water and swell, leading to the initiation of growth.
Question 8: What term describes the equilibrium point reached in imbibition when there is no further increase in the volume of the material?
a) Osmotic point
b) Equilibrium point
c) Saturation point
d) Imbibition point
Answer: c) Saturation point
Explanation: The saturation point in imbibition is the equilibrium point where the material has absorbed as much water as it can and further absorption is limited.
Question 9: Which physical property of water allows it to be absorbed by dry materials during imbibition?
a) High viscosity
b) Low surface tension
c) High density
d) Low vapor pressure
Answer: b) Low surface tension
Explanation: Water’s low surface tension allows it to wet and be absorbed by porous materials during imbibition.
Question 10: What is the primary force responsible for the swelling of materials during imbibition?
a) Electrostatic force
b) Gravitational force
c) Osmotic force
d) Magnetic force
Answer: c) Osmotic force
Explanation: Osmotic force generated by the absorption of water causes the swelling of materials during imbibition.
Question 11: What is the significance of imbibition in the context of agriculture?
a) It helps plants photosynthesize more efficiently.
b) It aids in the movement of nutrients within plants.
c) It supports water transport through the xylem.
d) It enables seed germination and initial growth.
Answer: d) It enables seed germination and initial growth.
Explanation: Imbibition is crucial for seed germination, as dry seeds absorb water to initiate growth and metabolic processes.
Question 12: Which part of a dry seed is primarily responsible for imbibition during germination?
a) Seed coat
b) Embryo
c) Endosperm
d) Radicle
Answer: a) Seed coat
Explanation: The seed coat is primarily responsible for imbibition during germination, as it allows water to enter the seed and initiate growth.
Question 13: What is the outcome of imbibition in the context of cooking and food preparation?
a) Reduced water content in food
b) Softening and swelling of dry food materials
c) Production of gas bubbles in food
d) Decreased nutrient content in food
Answer: b) Softening and swelling of dry food materials
Explanation: Imbibition can cause dry food materials to soften and swell, which is often desired in cooking and food preparation.
Question 14: Which of the following materials would likely show the highest imbibition rate?
a) Metal
b) Ceramic
c) Wood
d) Plastic
Answer: c) Wood
Explanation: Wood is a porous material with a high imbibition capacity due to its cellulose structure.
Question 15: What is the relationship between imbibition and germination in plant seeds
a) Imbibition hinders germination.
b) Germination causes imbibition.
c) Imbibition is a result of germination.
d) Imbibition is unrelated to germination.
Answer: b) Germination causes imbibition.
Explanation: During germination, seeds absorb water through imbibition, which initiates the metabolic processes required for growth.
Question 16: Which type of force is responsible for the absorption of water during imbibition?
a) Gravitational force
b) Electromagnetic force
c) Osmotic force
d) Centrifugal force
Answer: c) Osmotic force
Explanation: Osmotic force is generated as water is absorbed by dry materials, driving the imbibition process.
Question 17: What is the role of imbibition in soil formation?
a) It helps compact soil particles.
b) It contributes to the erosion of soil.
c) It assists in breaking down rock particles.
d) It aids in the loosening and expansion of soil particles.
Answer: d) It aids in the loosening and expansion of soil particles.
Explanation: Imbibition can cause soil particles to swell, leading to the loosening and expansion of soil, which contributes to its structure.
Question 18: Which term describes the maximum amount of water that can be absorbed by a dry material during imbibition?
a) Absorption limit
b) Imbibition capacity
c) Osmotic potential
d) Hydrophilic capacity
Answer: b) Imbibition capacity
Explanation: Imbibition capacity is the maximum amount of water a dry material can absorb during imbibition.
Question 19: What is the primary force responsible for the movement of water within plant tissues during imbibition?
a) Gravity
b) Capillarity
c) Osmotic pressure
d) Hydrostatic pressure
Answer: c) Osmotic pressure
Explanation: Osmotic pressure drives the movement of water within plant tissues during imbibition.
Question 20: Which term is used to describe the point at which imbibition reaches its maximum and no further swelling occurs?
a) Equilibrium point
b) Saturation point
c) Maximum point
d) Swelling point
Answer: b) Saturation point
Explanation: The saturation point is reached when imbibition has caused the material to swell to its maximum capacity, and no further increase in volume occurs.
Absorption of Water by Plants MCQs
Question 1: How do plants absorb water from the soil?
a) Through their leaves
b) Through their stems
c) Through their roots
d) Through their flowers
Answer: c) Through their roots
Explanation: Plants absorb water primarily through their roots, which have specialized structures called root hairs that enhance water uptake.
Question 2: Which tissue in plant roots is responsible for water absorption?
a) Xylem
b) Phloem
c) Cortex
d) Epidermis
Answer: d) Epidermis
Explanation: The epidermis of plant roots, particularly the root hairs, is responsible for the absorption of water from the soil.
Question 3: What is the term for the process by which water moves from the soil into the roots of a plant?
a) Transpiration
b) Respiration
c) Osmosis
d) Imbibition
Answer: c) Osmosis
Explanation: Osmosis is the process by which water moves from an area of lower solute concentration (soil) to an area of higher solute concentration (plant root cells).
Question 4: Which factor affects the rate of water absorption by plant roots?
a) Soil pH
b) Air temperature
c) Leaf color
d) Stem length
Answer: a) Soil pH
Explanation: Soil pH can affect the availability of nutrients and minerals in the soil, which can influence water absorption by plant roots.
Question 5: What is the primary driving force for the movement of water from the soil to the roots?
a) Capillary action
b) Root pressure
c) Osmotic pressure
d) Transpiration
Answer: c) Osmotic pressure
Explanation: Osmotic pressure is the primary driving force that causes water to move from areas of low solute concentration (soil) to areas of high solute concentration (roots).
Question 6: Which part of a plant root is involved in the active uptake of minerals and nutrients?
a) Root hairs
b) Root cap
c) Cortex
d) Xylem
Answer: a) Root hairs
Explanation: Root hairs are responsible for the active uptake of minerals and nutrients from the soil into the plant root.
Question 7: What is the role of the endodermis in water absorption?
a) Protection of the root tip
b) Absorption of minerals
c) Regulation of water movement
d) Formation of root hairs
Answer: c) Regulation of water movement
Explanation: The endodermis has a selective barrier called the Casparian strip that regulates the movement of water and minerals into the vascular tissue of the root.
Question 8: Which type of water movement in plants is responsible for the upward transport of water from the roots to the leaves?
a) Osmosis
b) Transpiration
c) Capillary action
d) Root pressure
Answer: b) Transpiration
Explanation: Transpiration is the process by which water vapor exits plant leaves, creating a negative pressure that pulls water upward through the xylem from the roots.
Question 9: What is the term for the loss of water vapor from plant leaves?
a) Absorption
b) Respiration
c) Osmosis
d) Transpiration
Answer: d) Transpiration
Explanation: Transpiration is the loss of water vapor from plant leaves through small openings called stomata.
Question 10: How do root hairs increase the efficiency of water absorption?
a) By releasing water vapor
b) By producing oxygen
c) By increasing the surface area of the root
d) By reducing osmotic pressure
Answer: c) By increasing the surface area of the root
Explanation: Root hairs increase the surface area of the root, allowing for more efficient absorption of water and minerals from the soil.
Question 11: Which part of a plant root is responsible for anchoring the plant in the soil and absorbing water?
a) Root cap
b) Xylem
c) Phloem
d) Root hairs
Answer: d) Root hairs
Explanation: Root hairs are specialized structures on the surface of root cells that anchor the plant and absorb water and nutrients from the soil.
Question 12: How does the Casparian strip contribute to water absorption?
a) It prevents water loss from the roots.
b) It enhances root growth.
c) It facilitates water movement through the root epidermis.
d) It regulates the passage of water and minerals into the root vascular tissue.
Answer: d) It regulates the passage of water and minerals into the root vascular tissue.
Explanation: The Casparian strip is a waterproof barrier in the endodermis that forces water and minerals to pass through cells before entering the vascular tissue, regulating their uptake.
Question 13: What is the term for the movement of water within a plant, from the roots to the leaves and other aerial parts?
a) Transpiration
b) Osmosis
c) Absorption
d) Translocation
Answer: d) Translocation
Explanation: Translocation is the movement of water, minerals, and nutrients within a plant from the roots to the leaves and other aerial parts.
Question 14: Which plant structure is responsible for the upward transport of water from the roots to the leaves?
a) Phloem
b) Xylem
c) Stomata
d) Root hairs
Answer: b) Xylem
Explanation: The xylem is a specialized vascular tissue responsible for transporting water and minerals from the roots to the leaves.
Question 15: How does root pressure contribute to water absorption?
a) It creates a positive pressure that pushes water into the roots.
b) It creates a negative pressure that draws water into the roots.
c) It decreases the rate of transpiration.
d) It releases excess water from the roots.
Answer: a) It creates a positive pressure that pushes water into the roots.
Explanation: Root pressure is a positive pressure generated in the roots that can push water and nutrients upward in some plants, particularly during times of low transpiration.
Question 16: How does temperature affect water absorption by plants?
a) Higher temperatures increase water absorption.
b) Lower temperatures increase water absorption.
c) Temperature has no effect on water absorption.
d) Temperature affects the absorption of nutrients, not water.
Answer: a) Higher temperatures increase water absorption.
Explanation: Higher temperatures can increase the rate of metabolic processes, leading to increased water absorption and transpiration.
Question 17: What is the primary driving force behind the movement of water from the soil into the roots?
a) Gravity
b) Capillary action
c) Osmosis
d) Root pressure
Answer: c) Osmosis
Explanation: Osmosis is the movement of water across a semi-permeable membrane from an area of lower solute concentration (soil) to an area of higher solute concentration (root cells).
Question 18: How do mycorrhizal associations benefit water absorption in plants?
a) They hinder water absorption.
b) They increase root hair density.
c) They increase the surface area for water absorption.
d) They reduce the need for water absorption.
Answer: c) They increase the surface area for water absorption.
Explanation: Mycorrhizal associations involve fungi that form symbiotic relationships with plant roots, increasing the surface area for water and nutrient absorption.
Question 19: Which factor directly affects the water potential gradient and thus water absorption by plant roots?
a) Humidity
b) Wind speed
c) Air temperature
d) Soil moisture
Answer: d) Soil moisture
Explanation: Soil moisture directly affects the water potential gradient between the soil and the plant roots, influencing water absorption.
Question 20: Which process is responsible for the movement of water and dissolved substances through the plant’s xylem vessels?
a) Transpiration
b) Osmosis
c) Photosynthesis
d) Respiration
Answer: a) Transpiration
Explanation: Transpiration generates a negative pressure that draws water and dissolved substances from the roots through the xylem vessels to the leaves and other aerial parts of the plant.
Mechanism of Water Absorption MCQs
Question 1: What is the primary driving force for water absorption from the soil into the roots of plants?
a) Transpiration
b) Osmosis
c) Diffusion
d) Active transport
Answer: b) Osmosis
Explanation: Osmosis is the primary mechanism by which water moves from an area of lower solute concentration (soil) to an area of higher solute concentration (root cells).
Question 2: Which part of the plant root is directly involved in the active uptake of water and minerals?
a) Root cap
b) Cortex
c) Xylem
d) Root hairs
Answer: d) Root hairs
Explanation: Root hairs are specialized extensions of root epidermal cells that actively take up water and minerals from the soil.
Question 3: How do root hairs enhance water absorption?
a) By releasing water vapor
b) By producing oxygen
c) By increasing the surface area of the root
d) By reducing osmotic pressure
Answer: c) By increasing the surface area of the root
Explanation: Root hairs increase the surface area of the root, allowing for greater contact with the soil and more efficient water absorption.
Question 4: Which plant tissue acts as a selective barrier for water and solutes entering the root vascular system?
a) Epidermis
b) Cortex
c) Endodermis
d) Xylem
Answer: c) Endodermis
Explanation: The endodermis has a specialized structure called the Casparian strip that regulates the movement of water and solutes into the root vascular system.
Question 5: What is the significance of the Casparian strip in the endodermis?
a) It prevents water loss from the root hairs.
b) It enhances root growth.
c) It facilitates water movement through the root epidermis.
d) It ensures selective uptake of minerals and water.
Answer: d) It ensures selective uptake of minerals and water.
Explanation: The Casparian strip prevents the unregulated passage of water and solutes, allowing for the selective uptake of minerals and water into the root.
Question 6: Which process is responsible for the movement of water and minerals through the root cortex and endodermis?
a) Active transport
b) Diffusion
c) Facilitated transport
d) Osmosis
Answer: b) Diffusion
Explanation: Diffusion is the passive movement of substances from areas of higher concentration to areas of lower concentration, and it plays a role in moving water and minerals through the root cortex and endodermis.
Question 7: How does the negative pressure generated in the leaves during transpiration contribute to water absorption?
a) It pushes water from the soil into the roots.
b) It pulls water from the roots into the leaves.
c) It causes water to evaporate from the roots.
d) It decreases the osmotic potential of root cells.
Answer: b) It pulls water from the roots into the leaves.
Explanation: The negative pressure generated by transpiration creates a tension that pulls water from the roots through the xylem vessels and into the leaves.
Question 8: What is the primary function of the xylem in water absorption?
a) Active uptake of water from the soil
b) Storage of water and nutrients
c) Transport of water and minerals from roots to leaves
d) Protection of the root tip
Answer: c) Transport of water and minerals from roots to leaves
Explanation: The xylem is responsible for transporting water and minerals absorbed by the roots from the soil to the leaves and other aerial parts of the plant.
Question 9: How does root pressure contribute to water absorption?
a) It generates a negative pressure that draws water from the soil.
b) It generates a positive pressure that pushes water into the roots.
c) It enhances transpiration in the leaves.
d) It decreases the surface area of root hairs.
Answer: b) It generates a positive pressure that pushes water into the roots.
Explanation: Root pressure is the positive pressure generated in the roots that can push water into the root cells, contributing to water absorption.
Question 10: Which mechanism contributes to the efficient uptake of minerals by plant roots?
a) Diffusion
b) Active transport
c) Osmosis
d) Transpiration
Answer: b) Active transport
Explanation: Active transport is a process that uses energy to move substances against their concentration gradient, allowing for the efficient uptake of minerals by plant roots.
Question 11: How do mycorrhizal associations benefit water absorption in plants?
a) They inhibit water absorption.
b) They increase root hair density.
c) They enhance the release of oxygen.
d) They increase the surface area for nutrient and water absorption.
Answer: d) They increase the surface area for nutrient and water absorption.
Explanation: Mycorrhizal associations involve fungi that form symbiotic relationships with plant roots, increasing the surface area for nutrient and water absorption.
Question 12: How does the continuous movement of water through the xylem vessels assist in water absorption?
a) It generates a pressure that pushes water into the roots.
b) It maintains root pressure.
c) It prevents the formation of root hairs.
d) It creates a tension that draws water from the roots to the leaves.
Answer: d) It creates a tension that draws water from the roots to the leaves.
Explanation: The continuous movement of water through the xylem creates a negative pressure or tension that pulls water from the roots to the leaves through transpiration.
Question 13: What role does the cohesion-tension theory play in water absorption?
a) It hinders water absorption by creating tension.
b) It promotes active transport of water into the roots.
c) It explains how water is transported upward in the xylem.
d) It stimulates root pressure.
Answer: c) It explains how water is transported upward in the xylem.
Explanation: The cohesion-tension theory explains how water is pulled from the roots to the leaves through the xylem vessels, driven by the cohesion and adhesion of water molecules.
Question 14: How does the root epidermis contribute to water absorption?
a) By actively pumping water into the root cells
b) By releasing water vapor into the soil
c) By producing oxygen that facilitates water movement
d) By providing a barrier for selective water uptake
Answer: d) By providing a barrier for selective water uptake
Explanation: The root epidermis, particularly the root hairs, is responsible for selective water uptake and absorption from the soil.
Question 15: What is the relationship between transpiration and water absorption?
a) Transpiration inhibits water absorption.
b) Transpiration enhances water absorption.
c) Transpiration and water absorption are independent processes.
d) Transpiration prevents the movement of water through the xylem.
Answer: b) Transpiration enhances water absorption.
Explanation: Transpiration creates a negative pressure that enhances the movement of water from the soil into the roots and through the plant.
Question 16: How does the presence of solutes in root cells affect water absorption?
a) Solutes inhibit water absorption by increasing pressure.
b) Solutes attract water, promoting water absorption.
c) Solutes reduce the cohesion of water molecules.
d) Solutes create a barrier that prevents water entry.
Answer: b) Solutes attract water, promoting water absorption.
Explanation: The presence of solutes in root cells creates a lower water potential, attracting water from the soil through osmosis.
Question 17: What is the primary role of the endodermis in water absorption?
a) Active transport of water and minerals
b) Protection of the root tip
c) Regulation of water and nutrient movement
d) Oxygen release into the soil
Answer: c) Regulation of water and nutrient movement
Explanation: The endodermis has a selective barrier (Casparian strip) that regulates the movement of water and nutrients into the root vascular system.
Question 18: How does the cohesion of water molecules contribute to water absorption?
a) It hinders water absorption by creating pressure.
b) It breaks the tension in the xylem vessels.
c) It promotes active transport of water into the roots.
d) It enhances the movement of water through the xylem.
Answer: d) It enhances the movement of water through the xylem.
Explanation: Cohesion between water molecules allows for a continuous column of water to be pulled upward through the xylem vessels from the roots to the leaves.
Question 19: How does temperature affect the rate of water absorption by plants?
a) Higher temperatures increase water absorption.
b) Lower temperatures increase water absorption.
c) Temperature has no effect on water absorption.
d) Temperature affects the rate of transpiration, not water absorption.
Answer: a) Higher temperatures increase water absorption.
Explanation: Higher temperatures can increase the rate of metabolic processes, leading to increased water absorption.
Question 20: What is the relationship between root pressure and water absorption?
a) Root pressure hinders water absorption by creating tension.
b) Root pressure enhances water absorption by generating a positive pressure.
c) Root pressure has no effect on water absorption.
d) Root pressure prevents water absorption by reducing the osmotic potential.
Answer: b) Root pressure enhances water absorption by generating a positive pressure.
Explanation: Root pressure can contribute to water absorption by generating a positive pressure that pushes water into the root cells.
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