9th – Biology – Chapter 9 – PLANT PHYSIOLOGY

MCQs

1. What occurs when the guard cells become turgid?
   a) The stomata open b) The stomata close c) The leaves fall off d) The plant stops photosynthesis
2. How are mineral nutrients defined?
   a) Chemical elements absorbed from soil that help plant growth b) Substances found in fruit only c) Vitamins present in plants d) Organic molecules
3. Which mineral forms a part of chlorophyll?
   a) Magnesium b) Nitrogen c) Zinc d) Calcium
4. Which plant gives out mucilage as a waste product?
   a) Rubber plant b) Coniferous tree c) Ladyfinger d) Keekar tree
5. For what reason is transpiration called a “necessary evil”?
   a) It causes water loss but creates a pull for water transport b) It only occurs at night c) It prevents gaseous exchange d) It stops the plant from growing
6. How would you define transpiration?
   a) Loss of water from plant surfaces b) Absorption of minerals c) Root development d) Germination
7. Which type of plant grows in dry habitats?
   a) Hydrophytes b) Mesophytes c) Xerophytes d) Halophytes
8. Which plant tissue carries water up to the leaves?
   a) Epidermis b) Phloem c) Xylem d) Cortex
9. During the day, what is the main source of carbon dioxide for photosynthesis?
   a) Respiration and the environment b) Xylem transport c) Soil absorption d) Phloem unloading
10. What is meant by transpiration in plants?
    a) The uptake of water by roots b) The loss of water vapor from plant surfaces c) The transport of food in phloem d) The exchange of gases through stomata
11. Which micronutrient takes part in nitrogen metabolism?
    a) Boron b) Nickel c) Copper d) Manganese
12. How is diffusion defined?
    a) Movement of molecules from high to low concentration b) Active transport of nutrients c) Movement of water through a membrane d) Uptake of food particles
13. Which kind of plant lives in extremely dry habitats?
    a) Hydrophytes b) Mesophytes c) Xerophytes d) Halophytes
14. Which tissue in a cactus is used for storing water?
    a) Xylem b) Phloem c) Succulent stems or roots d) Epidermis
15. Which structure is chiefly responsible for transpiration?
    a) Xylem b) Phloem c) Stomata d) Cortex
16. In which group of plants are succulent organs found?
    a) Xerophytes b) Hydrophytes c) Mesophytes d) Halophytes
17. In what way do halophytes survive in salty water?
    a) By absorbing more water b) By absorbing salts to match external concentration c) By storing water in roots d) By developing thick cuticles
18. Which waste product does the rubber plant excrete?
    a) Gum b) Resin c) Latex d) Water
19. Which factor raises the rate of transpiration?
    a) High humidity b) Low temperature c) Increased wind speed d) Closed stomata
20. Which micronutrient is needed for photosynthesis and activates many enzymes?
    a) Iron b) Zinc c) Manganese d) Nickel
21. Which gas do plants give out through stomata during the daytime?
    a) Carbon dioxide b) Oxygen c) Nitrogen d) Water only
22. Which of the following is a typical example of a hydrophyte?
    a) Cactus b) Water lily c) Mango tree d) Grass
23. Which mineral nutrient is a major constituent of all biomolecules?
    a) Phosphorus b) Potassium c) Carbon d) Sulphur
24. What is the effect on a plant that suffers from nitrogen deficiency?
    a) Leaves turn yellow starting from younger leaves b) Growth slows down and leaves turn yellow c) Fruit formation increases d) Chlorophyll production increases
25. What function do lenticels perform?
    a) Transport of minerals b) Exchange of gases in woody stems c) Absorption of nutrients d) Support to the plant
26. At which point does food enter the sieve tubes of phloem?
    a) At the sink b) In the xylem c) Through stomata d) At the source
27. Which factor leads to an increase in transpiration?
    a) High humidity b) Low temperature c) Strong wind d) Less surface area
28. As per the table, what role does potassium play in plants?
    a) Component of chlorophyll b) Regulates opening and closing of stomata c) Activates enzymes d) Component of proteins
29. What takes place in guard cells when the stomata close in the evening?
    a) They gain turgor b) Potassium ions move out, and they lose turgor c) Glucose concentration increases d) They absorb more water
30. By which process does water enter the root hairs?
    a) Active transport b) Osmosis c) Diffusion d) Phloem movement
31. What name is given to the movement of food in plants?
    a) Transpiration b) Translocation c) Photosynthesis d) Respiration
32. Which of the following plants is a mesophyte?
    a) Cactus b) Water lily c) Maize (corn) d) Sea grass
33. Which symptom shows up first in nitrogen or magnesium deficiency?
    a) Yellowing of young leaves b) Increased fruit production c) Dropping of roots d) Yellowing of old leaves
34. Which adaptation do hydrophytes have for getting rid of excess water?
    a) Thick waxy cuticle b) Large number of stomata on upper leaf surfaces c) Deep roots d) Salt glands
35. What makes the stomata open in the daytime?
    a) Loss of potassium ions b) Decrease in glucose concentration c) Increase in turgor pressure of guard cells d) High humidity
36. Which mechanism mainly explains food transport in plants?
    a) Transpirational pull b) Osmosis c) Passive diffusion d) Pressure flow mechanism
37. Which plant nutrient is needed in large quantities?
    a) Iron b) Zinc c) Potassium d) Boron
38. By which process do plants get rid of excess water at night?
    a) Photosynthesis b) Guttation c) Transpiration d) Translocation
39. Which gas is taken in by plants at night?
    a) Oxygen b) Carbon dioxide c) Water vapor d) Nitrogen
40. For what function is phloem responsible?
    a) Transport of food b) Transport of minerals c) Water absorption d) Leaf growth
41. Which element do plants need for making chlorophyll?
    a) Phosphorus b) Calcium c) Sulphur d) Magnesium
42. Which of the following is a macronutrient needed by plants?
    a) Iron b) Nitrogen c) Molybdenum d) Boron
43. What are root hairs?
    a) Outgrowths of epidermal cells that absorb water b) Tiny leaves on roots c) Pores on stems d) Photosynthetic cells
44. Which tissue carries out the transport of food in plants?
    a) Xylem b) Root hairs c) Epidermis d) Phloem
45. What is the chief function of xylem in plants?
    a) Transport of food b) Transport of water and salts c) Gaseous exchange d) Excretion of wastes
46. Which force mainly pulls water upward through the xylem?
    a) Root pressure b) Transpirational pull c) Active transport d) Osmotic pressure
47. Which gas do plants mainly absorb at night?
    a) Oxygen b) Carbon dioxide c) Nitrogen d) Hydrogen
48. What function does sulphur serve in plants?
    a) Component of ATP b) Regulates stomatal movement c) Necessary for photosynthesis d) Component of proteins, vitamins, and enzymes
49. Which of these organisms is autotrophic?
    a) Fungi b) Some bacteria c) Humans d) Protozoa
50. In what way do plants get rid of excess carbon dioxide at night?
    a) Through guttation b) Through stomata and general surfaces c) By storing it in leaves d) Through xylem
51. How is guttation defined in plants?
    a) The evaporation of water from stomata b) The release of water droplets through leaf pores at night c) The condensation of water vapor on leaves d) The transport of food in phloem
52. In what way do halophytes avoid water loss in salty surroundings?
    a) By closing stomata permanently b) By absorbing salts to make their bodies hypertonic c) By storing water in vacuoles d) By reducing leaf surface area
53. Which of the following is not a macronutrient?
    a) Carbon b) Oxygen c) Potassium d) Iron
54. Which plant gives out latex as a waste product?
    a) Keekar tree b) Rubber plant c) Ladyfinger d) Coniferous tree
55. In which direction is food transported within a plant?
    a) From sink to source b) From leaves to air c) From roots to flowers d) From source to sink
56. How is osmosis defined?
    a) Transport of oxygen b) Movement of water through a semipermeable membrane c) Breaking down of food d) Conversion of sugar into starch
57. What keeps the water column in the xylem continuous?
    a) Wide diameter of xylem vessels b) High glucose concentration c) Stomatal closure d) Cohesion and adhesion of water molecules
58. Which role does magnesium have in plant life?
    a) Regulates the opening and closing of stomata b) Component of chlorophyll and activates enzymes c) Component of ATP and nucleic acids d) Necessary for sugar transport
59. In what way do some plants dispose of metabolic wastes?
    a) By storing them in leaves that eventually fall b) By transporting them to roots c) By converting them into sugars d) By releasing them through xylem
60. Through which structures does most transpiration take place in plants?
    a) Through lenticels b) Through stomata c) Through the cuticle d) Through root hairs
61. By which process does water pass from the soil into root cells?
    a) Active transport b) Osmosis c) Facilitated diffusion d) Bulk flow
62. Which mineral is vital for protein synthesis in plants?
    a) Magnesium b) Iron c) Nitrogen d) Zinc
63. Which structure controls transpiration?
    a) Mesophyll b) Guard cells c) Xylem d) Phloem
64. Which process involves the movement of molecules from high to low concentration without using energy?
    a) Active transport b) Osmosis c) Passive transport d) Transpiration
65. How is nutrition in plants defined?
    a) The process of exchanging gases with the environment b) The process in which food is prepared or obtained and converted into body substances c) The movement of water and salts through xylem d) The loss of water vapor from plant surfaces
66. What are macronutrients?
    a) Nutrients required in small amounts b) Nutrients that are not needed by plants c) Nutrients required in larger quantities d) Nutrients found only in seeds
67. Which statement is correct about the pressure flow mechanism of food transport?
    a) Water enters the source, creating pressure b) Water is pulled from the sink c) Movement of food in phloem is due to gravity d) Solutes move from low to high concentration
68. What name is given to the process of obtaining and preparing food for energy and growth?
    a) Respiration b) Photosynthesis c) Nutrition d) Excretion
69. What is the main function of root hairs?
    a) Transport of nutrients b) Storage of food c) Synthesis of proteins d) Increase surface area for absorption
70. Which gas do plants give off during the daytime?
    a) Oxygen b) Carbon dioxide c) Nitrogen d) Hydrogen
71. In what way does water pass from root hairs into the plant?
    a) By active transport only b) By transpiration pull alone c) By phloem transport d) By osmosis from soil to root hairs
72. What results when a plant does not get enough nitrogen?
    a) It turns blue b) Growth slows down, and leaves turn yellow c) It stops photosynthesis immediately d) Flowers turn black
73. In which condition is the rate of transpiration high?
    a) High humidity b) Low light intensity c) Wind d) Waterlogged soil
74. How do woody stems carry out gas exchange with their surroundings?
    a) Through stomata b) Through lenticels c) Through the cuticle d) Through root hairs
75. Which adaptation enables xerophytes to survive in dry conditions?
    a) Thin leaves b) Large stomata c) Deep roots d) Transparent leaves
76. Which ion is involved in the opening of stomata?
    a) Sodium (Na⁺) b) Potassium (K⁺) c) Calcium (Ca²⁺) d) Magnesium (Mg²⁺)
77. In what form is food transported in most plants?
    a) Glucose b) Sucrose c) Starch d) Maltose
78. What takes place at the sink according to the pressure flow mechanism?
    a) Sucrose is actively loaded into phloem b) Water flows into sieve tubes c) Sucrose is unloaded, reducing pressure d) Glucose is converted to starch
79. What part does phloem play in plants?
    a) Transport of water and salts b) Absorption of minerals c) Transport of food d) Gaseous exchange
80. By what means do root hairs take up salts from the soil?
    a) Diffusion b) Osmosis c) Active transport d) Filtration
81. Which tissue conducts water and mineral salts in plants?
    a) Phloem b) Epidermis c) Xylem d) Cortex
82. In what manner do plants take up magnesium from the soil?
    a) As nitrates b) Through passive transport only c) As a gas d) In ionic form (Mg²⁺)
83. What is meant by transport in plants?
    a) Movement of gases only b) Movement of substances like water, nutrients, and hormones c) Exchange of genetic material d) Absorption of sunlight
84. By what means do plants exchange gases?
    a) Through the roots b) Through the bark c) Through stomata and lenticels d) Through phloem

Short Questions

1. What are mineral nutrients?
2. What is the role of phloem in translocation?
3. Differentiate between macronutrients and micronutrients.
4. What happens to food at the sink?
5. How does humidity affect transpiration?
6. How does water move from root hairs to the cortex?
7. What happens when guard cells become turgid?
8. What are hydrophytes?
9. What is guttation?
10. What is adhesion in water transport?
11. Why do plants store waste materials instead of excreting them like animals?
12. What is the function of lenticels in gaseous exchange?
13. Why do plants need both macro and micronutrients?
14. What is the function of the epidermis in roots?
15. What is cohesion in water transport?
16. What are xerophytes?
17. What would happen if phloem stopped functioning in a plant?
18. How do the plants of rubber and keekar excrete their wastes?
19. Why is nitrogen important for plants?
20. How do environmental factors influence transpiration rate?
21. How does transpiration help in water movement?
22. Differentiate between Transpiration and guttation.
23. Define macronutrients and micronutrients and give examples.
24. Name two plant tissues responsible for transport.
25. What are succulents?
26. What role do stomata play in gaseous exchange?
27. Why is gaseous exchange necessary for plants?
28. Give an example of a hydrophyte.
29. What is the function of xylem?
30. Name some plants that excrete latex.
31. What is transport in plants?
32. What are nutrients?
33. Differentiate between transpiration and guttation.
34. Transpiration is the loss of water from plants. Is it a harmful phenomenon? If not, what is its importance?
35. What happens when guard cells lose turgor?
36. Why do desert plants have fewer stomata?
37. What are “source” and “sink” in phloem transport?
38. What are resins, and which plants produce them?
39. What happens to gaseous exchange during the day?
40. Why is transpiration considered a “necessary evil”?
41. How does leaf surface area affect transpiration?
42. How does transpiration help in cooling the plant?
43. What is the effect of magnesium deficiency in plants?
44. Differentiate between Lenticular transpiration and stomatal transpiration
45. How do plants excrete metabolic wastes?
46. What happens when a plant lacks nitrogen?
47. How does the movement of water in xylem differ from the movement of food in phloem?
48. Give examples of micronutrients.
49. Differentiate between Xylem and phloem.m
50. Define transpiration and its types.
51. How is food actively loaded into the phloem?
52. How do heterotrophic organisms obtain their food?
53. How do xerophytes conserve water?
54. Give an example of an autotrophic organism.
55. Differentiate between passive and active transport.
56. What is the role of root hairs in water absorption?
57. What are mesophytes?
58. Define osmosis.
59. Why do plants transpire more on a windy day compared to a humid one?
60. What is mucilage, and which plant excretes it?
61. State the roles of nitrogen and magnesium in plants.
62. What happens to gaseous exchange at night?
63. How does water enter the root hairs?
64. How does diffusion work in plants?
65. How is water transported from roots to leaves?
66. What are halophytes?
67. How is the transpirational pull important in plants?
68. Why is water necessary for plant survival?
69. What is transpiration pull?
70. How do plants excrete excess water?
71. What is the function of phloem?
72. Give an example of a xerophyte.
73. Differentiate between Hydrophytes and halophytes
74. Why do hydrophytes have more stomata on the upper leaf surface?
75. Give examples of macronutrients.
76. What is the pressure flow mechanism?
77. What is translocation?
78. Define mineral nutrition in plants.
79. What is nutrition?
80. Which trees excrete gums?
81. What is the role of xylem in water movement?
82. How do plants absorb magnesium?
83. How do halophytes survive in salty water?
84. Name the different tissues involved in water absorption in roots.
85. Give an example of a mesophyte.
86. What is transpirational pull?
87. How do guard cells regulate transpiration?
88. How do plants exchange gases?
89. How does temperature affect transpiration?
90. Differentiate between Hydrophytes and xerophytes.
91. What is transpiration?
92. How do carnivorous plants obtain nitrogen?
93. How do autotrophic organisms obtain their food?
94. How does wind speed affect transpiration?
95. What would happen if all stomata remained closed throughout the day?
96. In which form do plant roots absorb nitrogen?
97. What is the role of magnesium in plants?
98. How do hydrophytes remove excess water?

Long Questions

1. Explain the mechanism of food translocation by the Pressure Flow Mechanism.
2. Explain the process of guttation and how it differs from dew formation.
3. Describe the structure and function of xylem and phloem in transport.
4. How do plants store and remove metabolic wastes? Give examples of different waste products excreted by plants.
5. Describe the process of gaseous exchange in plants.
6. Define nutrition. Differentiate between macronutrients and micronutrients. Give examples of each.
7. Describe the mechanism of transport of water and salt in plants.
8. What are osmotic adjustments in plants? Explain how mesophytes, hydrophytes, xerophytes, and halophytes adapt to their environments.
9. Describe the role of nitrogen and magnesium in plant growth.
10. Describe the events involved in the opening and closing of stomata.
11. Discuss the importance of transpiration in plants.
12. How do plants excrete extra water and salts from their bodies?
13. Explain the different methods of excretion in plants with examples.
14. Describe the mechanisms/adaptations in plants for excretion of wastes.
15. What factors affect the rate of transpiration? Explain in detail.
16. Explain the internal structure of the root and describe the uptake of salt and water by the root.
17. Explain the pressure flow mechanism of food translocation in plants.
18. Explain the transport of water and salts in plants. How does transpirational pull help in water movement?
19. Describe the mechanism of transpiration and how guard cells regulate it.
20. Describe temperature, wind, and humidity as the factors affecting the rate of transpiration.
21. Explain osmotic adjustments in hydrophytes, xerophytes, and halophytes.
22. Why do xerophytes have adaptations like thick cuticles and fewer stomata?
23. Explain the process of water absorption in plants through roots.
24. How do plants exchange gases? Explain the role of stomata and lenticels in gaseous exchange.
25. How does transpiration help in the transport of water in tall plants?

Answer Key

1. a) The stomata open
2. a) Chemical elements absorbed from soil that help plant growth
3. a) Magnesium
4. c) Ladyfinger
5. a) It causes water loss but creates a pull for water transport
6. a) Loss of water from plant surfaces
7. c) Xerophytes
8. c) Xylem
9. a) Respiration and the environment
10. b) The loss of water vapor from plant surfaces
11. b) Nickel
12. a) Movement of molecules from high to low concentration
13. c) Xerophytes
14. c) Succulent stems or roots
15. c) Stomata
16. a) Xerophytes
17. b) By absorbing salts to match external concentration
18. c) Latex
19. c) Increased wind speed
20. a) Iron
21. b) Oxygen
22. b) Water lily
23. c) Carbon
24. b) Growth slows down and leaves turn yellow
25. b) Exchange of gases in woody stems
26. d) At the source
27. c) Strong wind
28. b) Regulates opening and closing of stomata
29. b) Potassium ions move out, and they lose turgor
30. b) Osmosis
31. b) Translocation
32. c) Maize (corn)
33. d) Yellowing of old leaves
34. b) Large number of stomata on upper leaf surfaces
35. c) Increase in turgor pressure of guard cells
36. d) Pressure flow mechanism
37. c) Potassium
38. b) Guttation
39. a) Oxygen
40. a) Transport of food
41. d) Magnesium
42. b) Nitrogen
43. a) Outgrowths of epidermal cells that absorb water
44. d) Phloem
45. b) Transport of water and salts
46. b) Transpirational pull
47. a) Oxygen
48. d) Component of proteins, vitamins, and enzymes
49. b) Some bacteria
50. b) Through stomata and general surfaces
51. b) The release of water droplets through leaf pores at night
52. b) By absorbing salts to make their bodies hypertonic
53. d) Iron
54. b) Rubber plant
55. d) From source to sink
56. b) Movement of water through a semipermeable membrane
57. d) Cohesion and adhesion of water molecules
58. b) Component of chlorophyll and activates enzymes
59. a) By storing them in leaves that eventually fall
60. b) Through stomata
61. b) Osmosis
62. c) Nitrogen
63. b) Guard cells
64. c) Passive transport
65. b) The process in which food is prepared or obtained and converted into body substances
66. c) Nutrients required in larger quantities
67. a) Water enters the source, creating pressure
68. c) Nutrition
69. d) Increase surface area for absorption
70. a) Oxygen
71. d) By osmosis from soil to root hairs
72. b) Growth slows down, and leaves turn yellow
73. c) Wind
74. b) Through lenticels
75. c) Deep roots
76. b) Potassium (K⁺)
77. b) Sucrose
78. c) Sucrose is unloaded, reducing pressure
79. c) Transport of food
80. c) Active transport
81. c) Xylem
82. d) In ionic form (Mg²⁺)
83. b) Movement of substances like water, nutrients, and hormones
84. c) Through stomata and lenticels