TRANSPORT IN PLANTS 100 BEST MCQS FOR NEET PRACTICE

TRANSPORT IN PLANTS 100 BEST MCQS FOR NEET PRACTICE

 

TRANSPORT IN PLANT

1. Which of the following tissues is primarily responsible for transporting water and nutrients in plants?
a) Epidermis
b) Xylem
c) Phloem
d) Parenchyma
*Answer: b) Xylem*
Explanation: Xylem is a specialized tissue primarily responsible for transporting water and minerals from roots to stems and leaves in plants.

2. What is the main function of phloem in plants?
a) Transporting water and minerals
b) Providing structural support
c) Transporting organic nutrients
d) Facilitating gas exchange
*Answer: c) Transporting organic nutrients*
Explanation: Phloem is responsible for transporting organic nutrients, such as sugars, produced during photosynthesis, from leaves to other parts of the plant.

3. Which of the following cells are responsible for the active transport of minerals into the xylem?
a) Companion cells
b) Tracheids
c) Sieve tube elements
d) Root hairs
*Answer: d) Root hairs*
Explanation: Root hairs are responsible for actively transporting minerals into the xylem from the soil solution through processes such as active transport.

4. The movement of water through a plant from roots to leaves is primarily driven by:
a) Capillary action
b) Transpiration pull
c) Osmosis
d) Root pressure
*Answer: b) Transpiration pull*
Explanation: Transpiration pull, caused by the evaporation of water from the leaves, creates tension in the xylem, which pulls water up from the roots.

5. What is the role of stomata in the process of transpiration?
a) Absorption of water from the soil
b) Release of oxygen produced during photosynthesis
c) Regulation of water loss and gas exchange
d) Transport of sugars in the phloem
*Answer: c) Regulation of water loss and gas exchange*
Explanation: Stomata regulate the rate of transpiration and facilitate gas exchange by opening and closing to control the movement of water vapor and gases.

6. Which of the following environmental factors does NOT affect the rate of transpiration?
a) Light intensity
b) Humidity
c) Temperature
d) pH of the soil
*Answer: d) pH of the soil*
Explanation: The pH of the soil primarily affects nutrient availability to the plant but has minimal direct impact on the rate of transpiration.

7. The process of movement of sugars from source to sink in plants occurs through:
a) Active transport
b) Diffusion
c) Translocation
d) Osmosis
*Answer: c) Translocation*
Explanation: Translocation is the process by which sugars are transported from the source (usually leaves) to the sink (areas of active growth or storage) in plants, primarily through the phloem.

8. Which of the following is NOT a primary factor affecting the rate of transpiration?
a) Wind speed
b) Surface area of leaves
c) Soil texture
d) Relative humidity
*Answer: c) Soil texture*
Explanation: While soil texture can indirectly affect transpiration by influencing water availability to the roots, it is not a primary factor affecting the rate of transpiration directly.

9. The movement of water through the plant against the force of gravity is facilitated by:
a) Root pressure
b) Transpiration pull
c) Osmotic pressure
d) Active transport
*Answer: b) Transpiration pull*
Explanation: Transpiration pull generates the force necessary to pull water up through the plant against gravity, from roots to leaves.

10. What is the significance of the Casparian strip in the endodermis?
a) It prevents water loss from the roots
b) It facilitates the uptake of minerals from the soil
c) It filters harmful substances from entering the plant
d) It ensures that water and minerals pass through the cytoplasm of endodermal cells
*Answer: d) It ensures that water and minerals pass through the cytoplasm of endodermal cells*
Explanation: The Casparian strip is a waterproof strip in the endodermis of plant roots that ensures all water and minerals must pass through the cytoplasm of endodermal cells, allowing the plant to selectively absorb nutrients and prevent harmful substances from entering.

11. Which of the following is NOT a component of the xylem tissue?
a) Tracheids
b) Companion cells
c) Vessels
d) Xylem parenchyma
*Answer: b) Companion cells*
Explanation: Companion cells are part of the phloem tissue, not the xylem tissue.

12. What is the role of the endodermis in plant roots?
a) Facilitate the movement of water and minerals into the xylem
b) Regulate gas exchange in the roots
c) Provide structural support to the root cap
d) Control the entry of water and minerals into the vascular cylinder
*Answer: d) Control the entry of water and minerals into the vascular cylinder*
Explanation: The endodermis in plant roots regulates the entry of water and minerals into the vascular cylinder through the selective permeability of its cells.

13. Which of the following is responsible for the cohesive property of water that aids in its movement through the xylem?
a) Hydrogen bonding
b) Covalent bonding
c) Ionic bonding
d) Van der Waals forces
*Answer: a) Hydrogen bonding*
Explanation: Hydrogen bonding between water molecules creates cohesion, allowing water to form a continuous column in the xylem and facilitating its upward movement through the plant.

14. What happens to the excess water absorbed by plant roots?
a) It is stored in the vacuoles of root cells
b) It is released through the stomata
c) It is used for photosynthesis
d) It is transported to the leaves for transpiration
*Answer: d) It is transported to the leaves for transpiration*
Explanation: Excess water absorbed by plant roots is transported to the leaves through the xylem and is ultimately released through transpiration.

15. Which of the following statements about guard cells is true?
a) Guard cells are responsible for the production of sugars in plants.
b) Guard cells regulate the opening and closing of stomata.
c) Guard cells provide mechanical support to the plant.
d) Guard cells transport water and minerals in the xylem.
*Answer: b) Guard cells regulate the opening and closing of stomata.*
Explanation: Guard cells control the opening and closing of stomata to regulate gas exchange and water loss in plants.

16. The movement of water from an area of high water potential to an area of low water potential through a semi-permeable membrane is known as:
a) Osmosis
b) Diffusion
c) Active transport
d) Transpiration
*Answer: a) Osmosis*
Explanation: Osmosis

is the passive movement of water molecules across a semi-permeable membrane from an area of high water potential to an area of low water potential.

17. Which of the following is NOT a role of roots in plants?
a) Anchoring the plant in the soil
b) Absorbing water and minerals
c) Producing sugars through photosynthesis
d) Providing support and stability
*Answer: c) Producing sugars through photosynthesis*
Explanation: Roots primarily serve functions such as anchoring the plant, absorbing water and minerals, and providing support and stability, while photosynthesis primarily occurs in leaves.

18. What is the function of the pericycle in plant roots?
a) It produces root hairs for absorption of water and minerals.
b) It synthesizes organic compounds for the plant.
c) It regulates the movement of water and minerals into the xylem.
d) It stores excess sugars produced during photosynthesis.
*Answer: c) It regulates the movement of water and minerals into the xylem.*
Explanation: The pericycle is a tissue in the root responsible for regulating the movement of water and minerals into the xylem.

19. Which of the following is NOT a type of vascular tissue in plants?
a) Xylem
b) Phloem
c) Epidermis
d) Cambium
*Answer: c) Epidermis*
Explanation: The epidermis is a protective outer layer of cells in plants and is not considered a vascular tissue.

20. In which direction does the flow of phloem sap typically occur in plants?
a) From roots to leaves
b) From leaves to roots
c) Bidirectional
d) Random
*Answer: b) From leaves to roots*
Explanation: Phloem sap typically flows from the source (areas of sugar production, usually leaves) to the sink (areas of sugar utilization or storage) in plants.

21. Which of the following best describes the function of the root hairs?
a) To absorb water and minerals from the soil
b) To provide structural support to the root
c) To synthesize organic nutrients for the plant
d) To regulate gas exchange in the root
*Answer: a) To absorb water and minerals from the soil*
Explanation: Root hairs are extensions of root epidermal cells that increase the surface area for absorption of water and minerals from the soil.

22. The movement of water across a plant cell membrane from an area of high water potential to an area of low water potential is primarily driven by:
a) Active transport
b) Facilitated diffusion
c) Osmosis
d) Transpiration
*Answer: c) Osmosis*
Explanation: Osmosis is the passive movement of water across a selectively permeable membrane down its concentration gradient, from an area of high water potential to an area of low water potential.

23. What is the function of the root cap in plant roots?
a) Absorption of water and minerals
b) Protection of the root apical meristem
c) Facilitation of gas exchange
d) Production of hormones for root growth
*Answer: b) Protection of the root apical meristem*
Explanation: The root cap protects the delicate root apical meristem as the root grows through the soil.

24. Which of the following is NOT a type of cell found in the xylem tissue?
a) Tracheids
b) Parenchyma cells
c) Vessel elements
d) Sieve tube elements
*Answer: d) Sieve tube elements*
Explanation: Sieve tube elements are found in the phloem tissue, not the xylem tissue.

25. What is the main function of the endodermis in plant roots?
a) Facilitating the movement of water and minerals into the xylem
b) Providing structural support to the root
c) Protecting the root apical meristem
d) Regulating the entry of water and minerals into the vascular cylinder
*Answer: d) Regulating the entry of water and minerals into the vascular cylinder*
Explanation: The endodermis regulates the passage of water and minerals into the vascular cylinder of the root, ensuring selective uptake of nutrients.

26. Which of the following is NOT a characteristic of water that contributes to its importance in plant transport?
a) Cohesion
b) Adhesion
c) High heat capacity
d) Low surface tension
*Answer: d) Low surface tension*
Explanation: Water has high surface tension, which contributes to its cohesion and allows it to be pulled upward through the xylem in plants.

27. The process by which sugars are loaded into the phloem at the source and unloaded at the sink is known as:
a) Transpiration
b) Translocation
c) Osmosis
d) Diffusion
*Answer: b) Translocation*
Explanation: Translocation is the process of sugars being transported through the phloem from source to sink in plants.

28. Which of the following is NOT a factor affecting the rate of transpiration?
a) Light intensity
b) Humidity
c) Atmospheric pressure
d) Soil pH
*Answer: d) Soil pH*
Explanation: Soil pH does not directly affect the rate of transpiration in plants.

29. What is the main function of the vascular cambium in plants?
a) Transporting water and nutrients
b) Producing new xylem and phloem
c) Facilitating gas exchange
d) Providing structural support
*Answer: b) Producing new xylem and phloem*
Explanation: The vascular cambium is responsible for producing new cells that differentiate into xylem and phloem, contributing to secondary growth in plants.

30. What is the primary role of the sieve tube elements in the phloem?
a) Transporting water and minerals
b) Providing structural support
c) Facilitating the movement of sugars
d) Synthesizing organic nutrients
*Answer: c) Facilitating the movement of sugars*
Explanation: Sieve tube elements are specialized cells in the phloem responsible for transporting sugars and other organic nutrients throughout the plant.

31. Which of the following statements about root pressure is true?
a) Root pressure is the primary mechanism for the upward movement of water in tall trees.
b) Root pressure is generated by the active transport of sugars into the root.
c) Root pressure is highest during periods of drought.
d) Root pressure can cause guttation in plants.
*Answer: d) Root pressure can cause guttation in plants.*
Explanation: Root pressure, the force exerted by roots as a result of water uptake, can cause guttation, the exudation of water droplets from the tips of leaves, in certain plant species.

32. Which of the following is NOT a function of the stem in plants?
a) Transporting water and nutrients
b) Providing support to leaves and flowers
c) Absorbing water and minerals from the soil
d) Conducting photosynthesis
*Answer: c) Absorbing water and minerals from the soil*
Explanation: While the stem transports water and nutrients from roots to leaves and provides support to leaves and flowers, it does not absorb water and minerals from the soil.

33. What is the significance of transpiration in plants?
a) It facilitates the movement of water and minerals from roots to leaves.
b) It provides structural support to the plant.
c) It produces sugars through photosynthesis.
d) It regulates gas exchange and water loss.
*Answer: d) It regulates gas exchange and water loss.*
Explanation: Transpiration regulates gas exchange and water loss in plants by controlling the opening and closing of stomata, thus influencing the movement of water and minerals through the plant.

34. Which of the following is NOT a component of the symplast pathway for water movement in plants?
a) Apoplast
b) Plasmodesmata
c) Xylem vessels
d) Cytoplasm
*Answer: c) Xylem vessels*
Explanation: The symplast pathway involves the movement of water and solutes through the interconnected cytoplasm of plant cells via plasmodesmata, bypassing the xylem vessels.

35. The movement of water and minerals from the soil into the roots is primarily driven by:
a) Transpiration pull
b) Root pressure
c) Osmotic pressure
d) Active transport
*Answer: d) Active transport*
Explanation: Active transport processes in the root cells actively pump water and minerals from the soil into the roots against their concentration gradient.

36. Which of the following is NOT a function of the root system in plants?
a) Anchoring the plant in the soil
b) Absorbing water and minerals
c) Conducting photosynthesis
d) Storing food reserves
*Answer: c) Conducting photosynthesis*
Explanation: The root system primarily serves functions such as anchoring the plant, absorbing water and minerals, and storing food reserves, while photosynthesis primarily occurs in the shoot system.

37. What is the main function of the root hairs in plants?
a) Producing hormones for root growth
b) Providing structural support to the root
c) Absorbing water and minerals from the soil
d) Facilitating gas exchange
*Answer: c) Absorbing water and minerals from the soil*
Explanation: Root hairs are extensions of root epidermal cells that increase the surface area for absorption of water and minerals from the soil.

38. What is the role of the endodermis in plant roots?
a) Facilitating the movement of water and minerals into the xylem
b) Protecting the root apical meristem
c) Providing structural support to the root
d) Regulating the entry of water and minerals into the vascular cylinder
*Answer: d) Regulating the entry of water and minerals into the vascular cylinder*
Explanation: The endodermis in plant roots regulates the passage of water and minerals into the vascular cylinder, ensuring selective uptake of nutrients.

39. Which of the following is responsible for the cohesion of water molecules, facilitating their movement through the xylem?
a) Hydrogen bonding
b) Covalent bonding
c) Ionic bonding
d) Van der Waals forces
*Answer: a) Hydrogen bonding*
Explanation: Hydrogen bonding between water molecules creates cohesion, allowing water to form a continuous column in the xylem and facilitating its upward movement through the plant.

40. The movement of water across a plant cell membrane from an area of high water potential to an area of low water potential is known as:
a) Osmosis
b) Diffusion
c) Active transport
d) Transpiration
*Answer: a) Osmosis*
Explanation: Osmosis is the passive movement of water molecules across a semi-permeable membrane from an area of high water potential to an area of low water potential.

41. What is the primary role of the Casparian strip in the endodermis?
a) It prevents water loss from the roots
b) It facilitates the uptake of minerals from the soil
c) It filters harmful substances from entering the plant
d) It ensures that water and minerals pass through the cytoplasm of endodermal cells
*Answer: d) It ensures that water and minerals pass through the cytoplasm of endodermal cells*
Explanation: The Casparian strip is a waterproof strip in the endodermis of plant roots that ensures all water and minerals must pass through the cytoplasm of endodermal cells, allowing the plant to selectively absorb nutrients and prevent harmful substances from entering.

42. Which of the following is NOT a type of cell found in the xylem tissue?
a) Tracheids
b) Parenchyma cells
c) Vessel elements
d) Sieve tube elements
*Answer: d) Sieve tube elements*
Explanation: Sieve tube elements are found in the phloem tissue, not the xylem tissue.

43. What is the main function of the vascular cambium in plants?
a) Transporting water and nutrients
b) Producing new xylem and phloem
c) Facilitating gas exchange
d) Providing structural support
*Answer: b) Producing new xylem and phloem*
Explanation: The vascular cambium is responsible for producing new cells that differentiate into xylem and phloem, contributing to secondary growth in plants.

44. Which of the following is NOT a component of the symplast pathway for water movement in plants?
a) Apoplast
b) Plasmodesmata
c) Xylem vessels
d) Cytoplasm
*Answer: c) Xylem vessels*
Explanation: The symplast pathway involves the movement of water and solutes through the interconnected cytoplasm of plant cells via plasmodesmata, bypassing the xylem vessels.

45. The movement of water and minerals from the soil into the roots is primarily driven by:
a) Transpiration pull
b) Root pressure
c) Osmotic pressure
d) Active transport
*Answer: d) Active transport*
Explanation: Active transport processes in the root cells actively pump water and minerals from the soil into the roots against their concentration gradient.

46. Which of the following is NOT a function of the stem in plants?
a) Transporting water and nutrients
b) Providing support to leaves and flowers
c) Absorbing water and minerals from the soil
d) Conducting photosynthesis
*Answer: c) Absorbing water and minerals from the soil*
Explanation: While the stem transports water and nutrients from roots to leaves and provides support to leaves and flowers, it does not absorb water and minerals from the soil.

47. What is the primary role of the sieve tube elements in the phloem?
a) Transporting water and minerals
b) Providing structural support
c) Facilitating the movement of sugars
d) Synthesizing organic nutrients
*Answer: c) Facilitating the movement of sugars*
Explanation: Sieve tube elements are specialized cells in the phloem responsible for transporting sugars and other organic nutrients throughout the plant.

48. Which of the following statements about root pressure is true?
a) Root pressure is the primary mechanism for the upward movement of water in tall trees.
b) Root pressure is generated by the active transport of sugars into the root.
c) Root pressure is highest during periods of drought.
d) Root pressure can cause guttation in plants.
*Answer: d) Root pressure can cause guttation in plants.*
Explanation: Root pressure, the force exerted by roots as a result of water uptake, can cause guttation, the exudation of water droplets from the tips of leaves, in certain plant species.

49. Which of the following is NOT a function of the shoot system in plants?
a) Absorbing water and minerals from the soil
b) Conducting photosynthesis
c) Providing support to leaves and flowers
d) Producing flowers and fruits
*Answer: a) Absorbing water and minerals from the soil*
Explanation: The shoot system primarily serves functions such as conducting photosynthesis, providing support to leaves and flowers, and producing flowers and fruits, while absorption of water and minerals primarily occurs in the root system.

50. What is the main function of the guard cells in leaves?
a) Producing sugars through photosynthesis
b) Facilitating the movement of water and minerals
c) Regulating the opening and closing of stomata
d) Providing structural support to the leaf
*Answer: c) Regulating the opening and closing of stomata*
Explanation: Guard cells control the opening and closing of stomata to regulate gas exchange and water loss in leaves.

51. Which of the following is NOT a role of the stem in plants?
a) Transporting water and nutrients
b) Providing support to leaves and flowers
c) Conducting photosynthesis
d) Producing hormones for plant growth
*Answer: c) Conducting photosynthesis*
Explanation: While stems transport water and nutrients, provide support to leaves and flowers, and produce hormones for plant growth, they do not conduct photosynthesis, which primarily occurs in the leaves.

52. The primary function of the epidermis in plant leaves is to:
a) Facilitate gas exchange
b) Absorb water and minerals
c) Provide structural support
d) Prevent water loss
*Answer: d) Prevent water loss*
Explanation: The epidermis in plant leaves is covered by a waxy cuticle that helps prevent water loss through transpiration.

53. What is the role of the spongy mesophyll in plant leaves?
a) Facilitate gas exchange
b) Absorb water and minerals
c) Provide structural support
d) Produce sugars through photosynthesis
*Answer: a) Facilitate gas exchange*
Explanation: The spongy mesophyll in plant leaves contains air spaces that facilitate gas exchange, allowing for the diffusion of gases such as oxygen and carbon dioxide.

54. Which of the following structures is NOT part of the leaf’s vascular system?
a) Xylem
b) Phloem
c) Stomata
d) Veins
*Answer: c) Stomata*
Explanation: Stomata are specialized pores on the leaf surface that regulate gas exchange and water loss, but they are not part of the leaf’s vascular system.

55. The movement of sugars from photosynthetic cells to other parts of the plant occurs primarily through:
a) Osmosis
b) Diffusion
c) Active transport
d) Translocation
*Answer: d) Translocation*
Explanation: Translocation is the process by which sugars produced in photosynthetic cells are transported through the phloem to other parts of the plant for use or storage.

56. Which of the following is NOT a factor that affects the rate of transpiration?
a) Light intensity
b) Temperature
c) Atmospheric pressure
d) Soil fertility
*Answer: d) Soil fertility*
Explanation: Soil fertility does not directly affect the rate of transpiration in plants.

57. Guttation is the process by which plants:
a) Release oxygen during photosynthesis
b) Absorb water and minerals from the soil
c) Exude water droplets from leaf margins
d) Convert light energy into chemical energy
*Answer: c) Exude water droplets from leaf margins*
Explanation: Guttation occurs when excess water pressure in the plant’s vascular system causes water to exude from specialized structures at the leaf margins, typically during periods of high root pressure.

58. What is the significance of the apoplast pathway in plant transport?
a) It allows for the movement of water and solutes through the cytoplasm of cells.
b) It provides a direct route for water movement across cell membranes.
c) It facilitates the selective uptake of minerals by plant roots.
d) It transports sugars and amino acids between plant cells.
*Answer: b) It provides a direct route for water movement across cell membranes.*
Explanation: The apoplast pathway involves the movement of water and solutes through the cell walls and intercellular spaces, bypassing the cytoplasm, providing a rapid and uninterrupted route for water movement across cell membranes.

59. Which of the following environmental factors does NOT influence the rate of transpiration?
a) Light intensity
b) Humidity
c) Soil texture
d) Wind speed
*Answer: c) Soil texture*
Explanation: While soil texture can indirectly affect water availability to the roots, it does not directly influence the rate of transpiration.

60. The process by which water moves through plant roots from cell to cell until it reaches the xylem is known as:
a) Transpiration
b) Guttation
c) Osmosis
d) Apoplastic flow
*Answer: d) Apoplastic flow*
Explanation: Apoplastic flow is the movement of water through plant roots via the apoplast pathway, which involves the movement of water and solutes through cell walls and intercellular spaces.

61. Which of the following is NOT a role of the cuticle in plant leaves?
a) Preventing water loss
b) Protecting against pathogens
c) Facilitating gas exchange
d) Reducing UV radiation damage
*Answer: c) Facilitating gas exchange*
Explanation: The cuticle is a waxy layer on the outer surface of plant leaves that helps prevent water loss and protects against pathogens and UV radiation, but it does not facilitate gas exchange.

62. The movement of sugars from photosynthetic cells to other parts of the plant occurs primarily through:
a) Osmosis
b) Diffusion
c) Active transport
d) Translocation
*Answer: d) Translocation*
Explanation: Translocation is the process by which sugars produced in photosynthetic cells are transported through the phloem to other parts of the plant for use or storage.

63. Which of the following is NOT a factor that affects the rate of transpiration?
a) Light intensity
b) Temperature
c) Atmospheric pressure
d) Soil fertility
*Answer: d) Soil fertility*
Explanation: Soil fertility does not directly affect the rate of transpiration in plants.

64. Guttation is the process by which plants:
a) Release oxygen during photosynthesis
b) Absorb water and minerals from the soil
c) Exude water droplets from leaf margins
d) Convert light energy into chemical energy
*Answer: c) Exude water droplets from leaf margins*
Explanation: Guttation occurs when excess water pressure in the plant’s vascular system causes water to exude from specialized structures at the leaf margins, typically during periods of high root pressure.

65. What is the significance of the apoplast pathway in plant transport?
a) It allows for the movement of water and solutes through the cytoplasm of cells.
b) It provides a direct route for water movement across cell membranes.
c) It facilitates the selective uptake of minerals by plant roots.
d) It transports sugars and amino acids between plant cells.
*Answer: b) It provides a direct route for water movement across cell membranes.*
Explanation: The apoplast pathway involves the movement of water and solutes through the cell walls and intercellular spaces, bypassing the cytoplasm, providing a rapid and uninterrupted route for water movement across cell membranes.

66. Which of the following environmental factors does NOT influence the rate of transpiration?
a) Light intensity
b) Humidity
c) Soil texture
d) Wind speed
*Answer: c) Soil texture*
Explanation: While soil texture can indirectly affect water availability to the roots, it does not directly influence the rate of transpiration.

67. The process by which water moves through plant roots from cell to cell until it reaches the xylem is known as:
a) Transpiration
b) Guttation
c) Osmosis
d) Apoplastic flow
*Answer: d) Apoplastic flow*
Explanation: Apoplastic flow is the movement of water through plant roots via the apoplast pathway, which involves the movement of water and solutes through cell walls and intercellular spaces.

68. Which of the following is NOT a role of the cuticle in plant leaves?
a) Preventing water loss
b) Protecting against pathogens
c) Facilitating gas exchange
d) Reducing UV radiation damage
*Answer: c) Facilitating gas exchange*
Explanation: The cuticle is a waxy layer on the outer surface of plant leaves that helps prevent water loss and protects against pathogens and UV radiation, but it does not facilitate gas exchange.

69. The movement of sugars from leaves to other parts of the plant occurs primarily through:
a) Osmosis
b) Diffusion
c) Active transport
d) Translocation
*Answer: d) Translocation*
Explanation: Translocation is the process by which sugars produced in leaves during photosynthesis are transported through the phloem to other parts of the plant for use or storage.

70. Which of the following is NOT a factor that affects the rate of transpiration?
a) Wind speed
b) Light intensity
c) Soil fertility
d) Relative humidity
*Answer: c) Soil fertility*
Explanation: Soil fertility does not directly affect the rate of transpiration in plants.

71. Guttation is most likely to occur when:
a) There is high atmospheric pressure
b) The soil is dry
c) The stomata are closed
d) Root pressure is high
*Answer: d) Root pressure is high*
Explanation: Guttation occurs when excess water pressure in the plant’s vascular system causes water to exude from specialized structures at the leaf margins, typically during periods of high root pressure.

72. What is the main function of the apoplast pathway in plant roots?
a) Transporting water and minerals into the xylem
b) Regulating gas exchange in the root
c) Facilitating the movement of sugars in the phloem
d) Protecting the root apical meristem
*Answer: a) Transporting water and minerals into the xylem*
Explanation: The apoplast pathway in plant roots allows water and minerals to move through the cell walls and intercellular spaces, providing a rapid route for water uptake and transport into the xylem.

73. Which of the following is NOT a function of the root cap in plant roots?
a) Protecting the root apical meristem
b) Facilitating the uptake of water and minerals
c) Producing hormones for root growth
d) Regulating gas exchange
*Answer: d) Regulating gas exchange*
Explanation: The root cap protects the delicate root apical meristem as the root grows through the soil and secretes mucilage to lubricate the passage through the soil, but it does not directly regulate gas exchange.

74. The movement of water and minerals from roots to leaves in plants is primarily driven by:
a) Root pressure
b) Transpiration pull
c) Osmotic pressure
d) Capillary action
*Answer: b) Transpiration pull*
Explanation: Transpiration pull, caused by the evaporation of water from the leaves, creates tension in the xylem, which pulls water up from the roots.

75. What is the primary function of the endodermis in plant roots?
a) Facilitating the movement of water and minerals into the xylem
b) Protecting the root apical meristem
c) Providing structural support to the root
d) Regulating the entry of water and minerals into the vascular cylinder
*Answer: d) Regulating the entry of water and minerals into the vascular cylinder*
Explanation: The endodermis in plant roots regulates the passage of water and minerals into the vascular cylinder, ensuring selective uptake of nutrients.

76. Which of the following is NOT a function of the pericycle in plant roots?
a) Producing root hairs for absorption of water and minerals
b) Providing mechanical support to the root
c) Regulating the entry of water and minerals into the vascular cylinder
d) Differentiating into lateral roots
*Answer: b) Providing mechanical support to the root*
Explanation: While the pericycle does play a role in root development and lateral root formation, providing mechanical support to the root is not its primary function.

77. Which of the following environmental factors does NOT affect the rate of transpiration?
a) Atmospheric pressure
b) Relative humidity
c) Wind speed
d) Soil texture
*Answer: d) Soil texture*
Explanation: Soil texture primarily affects water availability to the roots but does not directly influence the rate of transpiration.

78. What is the primary function of the root hairs in plant roots?
a) Producing hormones for root growth
b) Providing structural support to the root
c) Absorbing water and minerals from the soil
d) Facilitating gas exchange
*Answer: c) Absorbing water and minerals from the soil*
Explanation: Root hairs are extensions of root epidermal cells that increase the surface area for absorption of water and minerals from the soil.

79. What is the role of the endodermis in plant roots?
a) Facilitating the movement of water and minerals into the xylem
b) Protecting the root apical meristem
c) Providing structural support to the root
d) Regulating the entry of water and minerals into the vascular cylinder
*Answer: d) Regulating the entry of water and minerals into the vascular cylinder*
Explanation: The endodermis in plant roots regulates the passage of water and minerals into the vascular cylinder, ensuring selective uptake of nutrients.

80. Which of the following is NOT a characteristic of water that contributes to its importance in plant transport?
a) Cohesion
b) Adhesion
c) High heat capacity
d) Low surface tension
*Answer: d) Low surface tension*
Explanation: Water has high surface tension, which contributes to its cohesion and allows it to be pulled upward through the xylem in plants.

81. The process by which sugars are loaded into the phloem at the source and unloaded at the sink is known as:
a) Transpiration
b) Translocation
c) Osmosis
d) Diffusion
*Answer: b) Translocation*
Explanation: Translocation is the process of sugars being transported through the phloem from source to sink in plants.

82. Which of the following is NOT a factor affecting the rate of transpiration?
a) Light intensity
b) Humidity
c) Atmospheric pressure
d) Soil pH
*Answer: d) Soil pH*
Explanation: Soil pH does not directly affect the rate of transpiration in plants.

83. What is the main function of the vascular cambium in plants?
a) Transporting water and nutrients
b) Producing new xylem and phloem
c) Facilitating gas exchange
d) Providing structural support
*Answer: b) Producing new xylem and phloem*
Explanation: The vascular cambium is responsible for producing new cells that differentiate into xylem and phloem, contributing to secondary growth in plants.

84. What is the primary role of the sieve tube elements in the phloem?
a) Transporting water and minerals
b) Providing structural support
c) Facilitating the movement of sugars
d) Synthesizing organic nutrients
*Answer: c) Facilitating the movement of sugars*
Explanation: Sieve tube elements are specialized cells in the phloem responsible for transporting sugars and other organic nutrients throughout the plant.

85. Which of the following statements about root pressure is true?
a) Root pressure is the primary mechanism for the upward movement of water in tall trees.
b) Root pressure is generated by the active transport of sugars into the root.
c) Root pressure is highest during periods of drought.
d) Root pressure can cause guttation in plants.
*Answer: d) Root pressure can cause guttation in plants.*
Explanation: Root pressure, the force exerted by roots as a result of water uptake, can cause guttation, the exudation of water droplets from the tips of leaves, in certain plant species.

86. Which of the following is NOT a function of the stem in plants?
a) Transporting water and nutrients
b) Providing support to leaves and flowers
c) Absorbing water and minerals from the soil
d) Conducting photosynthesis
*Answer: c) Absorbing water and minerals from the soil*
Explanation: While the stem transports water and nutrients from roots to leaves and provides support to leaves and flowers, it does not absorb water and minerals from the soil.

87. What is the significance of transpiration in plants?
a) It facilitates the movement of water and minerals from roots to leaves.
b) It provides structural support to the plant.
c) It produces sugars through photosynthesis.
d) It regulates gas exchange and water loss.
*Answer: d) It regulates gas exchange and water loss.*
Explanation: Transpiration regulates gas exchange and water loss in plants by controlling the opening and closing of stomata, thus influencing the movement of water and minerals through the plant.

88. Which of the following is NOT a component of the symplast pathway for water movement in plants?
a) Apoplast
b) Plasmodesmata
c) Xylem vessels
d) Cytoplasm
*Answer: c) Xylem vessels*
Explanation: The symplast pathway involves the movement of water and solutes through the interconnected cytoplasm of plant cells via plasmodesmata, bypassing the xylem vessels.

89. The movement of water and minerals from the soil into the roots is primarily driven by:
a) Transpiration pull
b) Root pressure
c) Osmotic pressure
d) Active transport
*Answer: d) Active transport*
Explanation: Active transport processes in the root cells actively pump water and minerals from the soil into the roots against their concentration gradient.

90. Which of the following is NOT a function of the root system in plants?
a) Anchoring the plant in the soil
b) Absorbing water and minerals
c) Conducting photosynthesis
d) Storing food reserves
*Answer: c) Conducting photosynthesis*
Explanation: The root system primarily serves functions such as anchoring the plant, absorbing water and minerals, and storing food reserves, while photosynthesis primarily occurs in the shoot system.

91. What is the main function of the guard cells in leaves?
a) Producing sugars through photosynthesis
b) Facilitating the movement of water and minerals
c) Regulating the opening and closing of stomata
d) Providing structural support to the leaf
*Answer: c) Regulating the opening and closing of stomata*
Explanation: Guard cells control the opening and closing of stomata to regulate gas exchange and water loss in leaves.

92. Which of the following is NOT a role of the stem in plants?
a) Transporting water and nutrients
b) Providing support to leaves and flowers
c) Conducting photosynthesis
d) Producing hormones for plant growth
*Answer: c) Conducting photosynthesis*
Explanation: While stems transport water and nutrients, provide support to leaves and flowers, and produce hormones for plant growth, they do not conduct photosynthesis, which primarily occurs in the leaves.

93. The primary function of the epidermis in plant leaves is to:
a) Facilitate gas exchange
b) Absorb water and minerals
c) Provide structural support
d) Prevent water loss
*Answer: d) Prevent water loss*
Explanation: The epidermis in plant leaves is covered by a waxy cuticle that helps prevent water loss through transpiration.

94. What is the role of the spongy mesophyll in plant leaves?
a) Facilitate gas exchange
b) Absorb water and minerals
c) Provide structural support
d) Produce sugars through photosynthesis
*Answer: a) Facilitate gas exchange*
Explanation: The spongy mesophyll in plant leaves contains air spaces that facilitate gas exchange, allowing for the diffusion of gases such as oxygen and carbon dioxide.

95. Which of the following structures is NOT part of the leaf’s vascular system?
a) Xylem
b) Phloem
c) Stomata
d) Veins
*Answer: c) Stomata*
Explanation: Stomata are specialized pores on the leaf surface that regulate gas exchange and water loss, but they are not part of the leaf’s vascular system.

96. The movement of sugars from photosynthetic cells to other parts of the plant occurs primarily through:
a) Osmosis
b) Diffusion
c) Active transport
d) Translocation
*Answer: d) Translocation*
Explanation: Translocation is the process by which sugars produced in photosynthetic cells are transported through the phloem to other parts of the plant for use or storage.

97. Which of the following is NOT a factor that affects the rate of transpiration?
a) Light intensity
b) Temperature
c) Atmospheric pressure
d) Soil fertility
*Answer: d) Soil fertility*
Explanation: Soil fertility does not directly affect the rate of transpiration in plants.

98. Guttation is the process by which plants:
a) Release oxygen during photosynthesis
b) Absorb water and minerals from the soil
c) Exude water droplets from leaf margins
d) Convert light energy into chemical energy
*Answer: c) Exude water droplets from leaf margins*
Explanation: Guttation occurs when excess water pressure in the plant’s vascular system causes water to exude from specialized structures at the leaf margins, typically during periods of high root pressure.

99. What is the significance of the apoplast pathway in plant transport?
a) It allows for the movement of water and solutes through the cytoplasm of cells.
b) It provides a direct route for water movement across cell membranes.
c) It facilitates the selective uptake of minerals by plant roots.
d) It transports sugars and amino acids between plant cells.
*Answer: b) It provides a direct route for water movement across cell membranes.*
Explanation: The apoplast pathway involves the movement of water and solutes through the cell walls and intercellular spaces, bypassing the cytoplasm, providing a rapid and uninterrupted route for water movement across cell membranes.

100. Which of the following environmental factors does NOT influence the rate of transpiration?
a) Light intensity
b) Humidity
c) Soil texture
d) Wind speed
*Answer: c) Soil texture*
Explanation: While soil texture can indirectly affect water availability to the roots, it does not directly influence the rate of transpiration.

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