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class 9 biology chapter 9 plant physiology mcqs

Section 1: Introduction and Basics

  1. Plant physiology is the study of:
    a) Structure of plants
    b) Functions and processes in plants
    c) Plant diseases
    d) Plant classification
    Answer: b) Functions and processes in plants

  2. The movement of water through a plant from roots to leaves is called:
    a) Photosynthesis
    b) Transpiration
    c) Translocation
    d) Respiration
    Answer: b) Transpiration

  3. The process by which plants lose water vapor through stomata is called
    a) Absorption
    b) Transpiration
    c) Evaporation
    d) Guttation
    Answer: b) Transpiration

  4. The opening and closing of stomata are controlled by:
    a) Xylem vessels
    b) Guard cells
    c) Phloem vessels
    d) Root hairs
    Answer: b) Guard cells

  5. Which of the following helps in the upward movement of water in plants?
    a) Gravity
    b) Root pressure
    c) Osmosis
    d) Both b and c
    Answer: d) Both b and c

  6. Transpiration helps in:
    a) Cooling the plant
    b) Transport of minerals
    c) Water movement
    d) All of these
    Answer: d) All of these

  7. The main site of transpiration in most plants is:
    a) Root hairs
    b) Stem
    c) Leaves
    d) Flowers
    Answer: c) Leaves

  8. Xylem vessels transport:
    a) Food from leaves to other parts
    b) Water and minerals from roots to leaves
    c) Oxygen to roots
    d) Sugars to roots
    Answer: b) Water and minerals from roots to leaves

  9. Phloem vessels transport:
    a) Water
    b) Minerals
    c) Food (sugars)
    d) Gases
    Answer: c) Food (sugars)

  10. Translocation in plants refers to the movement of:
    a) Water
    b) Food
    c) Oxygen
    d) Minerals
    Answer: b) Food

  11. Root hairs absorb water by the process of:
    a) Diffusion
    b) Active transport
    c) Osmosis
    d) Transpiration
    Answer: c) Osmosis

  12. The force exerted by roots to push water upward is called
    a) Transpiration pull
    b) Root pressure
    c) Capillary action
    d) Osmotic pressure
    Answer: b) Root pressure

  13. The loss of water in liquid form from leaf edges is called
    a) Transpiration
    b) Guttation
    c) Evaporation
    d) Photosynthesis
    Answer: b) Guttation

  14. Water movement in plants occurs due to:
    a) Cohesion and adhesion
    b) Gravity only
    c) Pressure only
    d) Active transport only
    Answer: a) Cohesion and adhesion

  15. The process of converting solar energy into chemical energy in plants is
    a) Respiration
    b) Photosynthesis
    c) Transpiration
    d) Fermentation
    Answer: b) Photosynthesis

  16. Which gas enters the plant during photosynthesis?
    a) Oxygen
    b) Carbon dioxide
    c) Nitrogen
    d) Hydrogen
    Answer: b) Carbon dioxide

  17. The main site of photosynthesis is
    a) Stem
    b) Leaf
    c) Root
    d) Flower
    Answer: b) Leaf

  18. Stomata mainly help in:
    a) Absorbing water
    b) Gas exchange and transpiration
    c) Food storage
    d) Mineral transport
    Answer: b) Gas exchange and transpiration

  19. Phloem is made up of
    a) Xylem vessels
    b) Sieve tubes and companion cells
    c) Root hairs
    d) Guard cells
    Answer: b) Sieve tubes and companion cells

  20. The upward movement of water in plants is primarily due to
    a) Translocation
    b) Transpiration pull
    c) Photosynthesis
    d) Respiration
    Answer: b) Transpiration pull

Section 2: Water Transport, Translocation & Photosynthesis

  1. Which phenomenon helps water molecules stick to the walls of xylem vessels?
    a) Cohesion
    b) Adhesion
    c) Diffusion
    d) Osmosis
    Answer: b) Adhesion

  2. The cohesive property of water helps in:
    a) Water sticking to xylem walls
    b) Water molecules sticking to each other
    c) Movement of sugars in phloem
    d) Opening of stomata
    Answer: b) Water molecules sticking to each other

  3. The movement of food in plants through phloem is called:
    a) Transpiration
    b) Translocation
    c) Osmosis
    d) Respiration
    Answer: b) Translocation

  4. Translocation of food in plants occurs:
    a) Only upward
    b) Only downward
    c) Both upward and downward
    d) Only laterally
    Answer: c) Both upward and downward

  5. The process by which plants lose water vapor mainly through stomata is affected by:
    a) Light intensity
    b) Temperature
    c) Wind speed
    d) All of these
    Answer: d) All of these

  6. Which gas is released during photosynthesis?
    a) Carbon dioxide
    b) Oxygen
    c) Nitrogen
    d) Hydrogen
    Answer: b) Oxygen

  7. The major site of photosynthesis in plants is
    a) Stem
    b) Leaf
    c) Root
    d) Flower
    Answer: b) Leaf

  8. Chlorophyll is located in which part of the plant cell?
    a) Mitochondria
    b) Chloroplast
    c) Nucleus
    d) Cytoplasm
    Answer: b) Chloroplast

  9. Which of the following is NOT required for photosynthesis?
    a) Sunlight
    b) Carbon dioxide
    c) Oxygen
    d) Water
    Answer: c) Oxygen

  10. The tiny pores on the leaf surface that allow gas exchange are called:
    a) Lenticels
    b) Stomata
    c) Root hairs
    d) Trichomes
    Answer: b) Stomata

  11. Root pressure helps in the movement of water:
    a) Downward only
    b) Upward only
    c) Both upward and downward
    d) None of these
    Answer: b) Upward only

  12. Which of the following statements about transpiration is false?
    a) It helps in cooling the plant
    b) It causes loss of water in liquid form
    c) It creates suction to pull water upward
    d) It occurs mostly through stomata
    Answer: b) It causes loss of water in liquid form

  13. Water moves from soil into roots due to:
    a) Pressure difference
    b) Osmosis
    c) Diffusion
    d) Active transport
    Answer: b) Osmosis

  14. Which part of the plant transports manufactured food?
    a) Xylem
    b) Phloem
    c) Cambium
    d) Cortex
    Answer: b) Phloem

  15. The main purpose of transpiration is to:
    a) Provide water for photosynthesis
    b) Maintain flow of minerals from roots
    c) Cool the plant
    d) All of the above
    Answer: d) All of the above

  16. Photosynthesis mainly takes place in which cells of the leaf?
    a) Palisade mesophyll
    b) Spongy mesophyll
    c) Epidermal cells
    d) Guard cells
    Answer: a) Palisade mesophyll

  17. The water absorbed by roots is transported to leaves through:
    a) Phloem
    b) Xylem
    c) Sieve tubes
    d) Parenchyma
    Answer: b) Xylem

  18. Guard cells control the size of stomata by:
    a) Changing their shape
    b) Changing their color
    c) Changing their number
    d) Changing their size permanently
    Answer: a) Changing their shape

  19. Which of the following is NOT a factor affecting transpiration?
    a) Temperature
    b) Humidity
    c) Soil type
    d) Light intensity
    Answer: c) Soil type

  20. The loss of water in liquid form through special pores called hydathodes is called:
    a) Transpiration
    b) Guttation
    c) Evaporation
    d) Respiration
    Answer: b) Guttation

Section 3: Photosynthesis, Respiration & Nutrient Transport

  1. Photosynthesis is a process that:
    a) Releases energy
    b) Stores energy
    c) Destroys chlorophyll
    d) Produces carbon dioxide
    Answer: b) Stores energy

  2. The energy required for photosynthesis comes from:
    a) Sunlight
    b) Soil nutrients
    c) Water
    d) Oxygen
    Answer: a) Sunlight

  3. During photosynthesis, oxygen is released from:
    a) Carbon dioxide
    b) Water
    c) Glucose
    d) Chlorophyll
    Answer: b) Water

  4. Which pigment is responsible for the green color of leaves?
    a) Carotene
    b) Chlorophyll
    c) Anthocyanin
    d) Xanthophyll
    Answer: b) Chlorophyll

  5. The process by which plants lose water vapor through stomata is called
    a) Guttation
    b) Transpiration
    c) Evaporation
    d) Respiration
    Answer: b) Transpiration

  6. The opening and closing of stomata are regulated by:
    a) Root hairs
    b) Guard cells
    c) Phloem
    d) Xylem
    Answer: b) Guard cells

  7. The movement of food substances in plants from leaves to other parts is called
    a) Transpiration
    b) Translocation
    c) Respiration
    d) Diffusion
    Answer: b) Translocation

  8. The primary function of xylem is to:
    a) Transport food
    b) Transport water and minerals
    c) Provide structural support only
    d) Store nutrients
    Answer: b) Transport water and minerals

  9. Which process produces energy by breaking down glucose in the presence of oxygen?
    a) Photosynthesis
    b) Aerobic respiration
    c) Anaerobic respiration
    d) Fermentation
    Answer: b) Aerobic respiration

  10. Stomata are mostly found on:
    a) Upper surface of leaves
    b) Lower surface of leaves
    c) Roots
    d) Stem
    Answer: b) Lower surface of leaves

  11. Water absorbed by roots moves to the leaves through:
    a) Phloem vessels
    b) Xylem vessels
    c) Guard cells
    d) Stomata
    Answer: b) Xylem vessels

  12. The loss of water from leaves as water vapor is essential for:
    a) Photosynthesis
    b) Transpiration pull
    c) Nutrient absorption
    d) Both a and b
    Answer: d) Both a and b

  13. Which of the following affects the rate of transpiration?
    a) Temperature
    b) Light intensity
    c) Wind speed
    d) All of these
    Answer: d) All of these

  14. The opening of stomata is caused by:
    a) Water loss from guard cells
    b) Water gain by guard cells
    c) Change in chlorophyll
    d) Change in soil moisture
    Answer: b) Water gain by guard cells

  15. The process of photosynthesis takes place mainly in:
    a) Guard cells
    b) Palisade mesophyll cells
    c) Xylem vessels
    d) Phloem vessels
    Answer: b) Palisade mesophyll cells

  16. The by-product of photosynthesis that is released into the atmosphere is:
    a) Carbon dioxide
    b) Oxygen
    c) Water vapor
    d) Nitrogen
    Answer: b) Oxygen

  17. The force that pulls water upward from roots to leaves during transpiration is called
    a) Root pressure
    b) Transpiration pull
    c) Osmotic pressure
    d) Atmospheric pressure
    Answer: b) Transpiration pull

  18. Translocation in plants moves:
    a) Water from roots to leaves
    b) Food from leaves to other parts
    c) Minerals from soil to roots
    d) Oxygen from leaves to atmosphere
    Answer: b) Food from leaves to other parts

  19. Phloem consists of:
    a) Vessel elements and tracheids
    b) Sieve tubes and companion cells
    c) Parenchyma and sclerenchyma
    d) Guard cells
    Answer: b) Sieve tubes and companion cells

  20. Which of the following processes require energy in plants?
    a) Photosynthesis
    b) Transpiration
    c) Active transport during nutrient absorption
    d) Diffusion of water
    Answer: c) Active transport during nutrient absorption

Section 4: Nutrient Absorption, Plant Growth & Environmental Effects

  1. Mineral nutrients are mainly absorbed by plants through:
    a) Leaves
    b) Root hairs
    c) Stomata
    d) Xylem vessels
    Answer: b) Root hairs

  2. The energy required for active transport of minerals into root cells is obtained from:
    a) ATP
    b) Sunlight
    c) Water pressure
    d) Glucose
    Answer: a) ATP

  3. The process by which plants take in oxygen and give out carbon dioxide is called:
    a) Photosynthesis
    b) Respiration
    c) Transpiration
    d) Translocation
    Answer: b) Respiration

  4. Which hormone primarily promotes cell elongation in plants?
    a) Auxin
    b) Cytokinin
    c) Gibberellin
    d) Ethylene
    Answer: a) Auxin

  5. Which plant hormone promotes seed germination and stem elongation?
    a) Auxin
    b) Gibberellin
    c) Cytokinin
    d) Abscisic acid
    Answer: b) Gibberellin

  6. Cytokinins primarily help in:
    a) Cell division
    b) Cell elongation
    c) Leaf fall
    d) Fruit ripening
    Answer: a) Cell division

  7. The hormone responsible for fruit ripening is:
    a) Auxin
    b) Gibberellin
    c) Ethylene
    d) Cytokinin
    Answer: c) Ethylene

  8. Abscisic acid mainly causes:
    a) Seed germination
    b) Leaf fall and dormancy
    c) Flowering
    d) Fruit ripening
    Answer: b) Leaf fall and dormancy

  9. Which part of the plant senses light and helps it grow towards it?
    a) Roots
    b) Stem tips
    c) Leaves
    d) Flowers
    Answer: b) Stem tips

  10. The process by which plants grow or move in response to light is called:
    a) Hydrotropism
    b) Phototropism
    c) Geotropism
    d) Thigmotropism
    Answer: b) Phototropism

  11. The downward growth of roots due to gravity is called:
    a) Phototropism
    b) Hydrotropism
    c) Geotropism (gravitropism)
    d) Thigmotropism
    Answer: c) Geotropism (gravitropism)

  12. The upward growth of stem against gravity is called:
    a) Negative geotropism
    b) Positive geotropism
    c) Phototropism
    d) Hydrotropism
    Answer: a) Negative geotropism

  13. Plants lose water mostly through:
    a) Root hairs
    b) Stomata
    c) Cuticle
    d) Phloem
    Answer: b) Stomata

  14. The absorption of water by roots depends mainly on:
    a) Osmotic pressure
    b) Root pressure
    c) Atmospheric pressure
    d) Photosynthesis
    Answer: a) Osmotic pressure

  15. The movement of water against gravity through narrow tubes is due to:
    a) Adhesion and cohesion
    b) Diffusion
    c) Osmosis
    d) Active transport
    Answer: a) Adhesion and cohesion

  16. Plant growth regulators are also called:
    a) Enzymes
    b) Hormones
    c) Vitamins
    d) Minerals
    Answer: b) Hormones

  17. The process of shedding old leaves by plants is called:
    a) Germination
    b) Photosynthesis
    c) Abscission
    d) Respiration
    Answer: c) Abscission

  18. The vascular tissue that transports sugars is called:
    a) Xylem
    b) Phloem
    c) Cambium
    d) Parenchyma
    Answer: b) Phloem

  19. Which plant hormone delays leaf fall?
    a) Cytokinin
    b) Abscisic acid
    c) Auxin
    d) Ethylene
    Answer: c) Auxin

  20. The loss of water through stomata helps in:
    a) Cooling the plant
    b) Transporting minerals
    c) Maintaining water flow
    d) All of the above
    Answer: d) All of the above

Section 5: Advanced Concepts & Summary

  1. Which pigment besides chlorophyll helps in photosynthesis by capturing light energy?
    a) Carotenoids
    b) Hemoglobin
    c) Anthocyanins
    d) Melanin
    Answer: a) Carotenoids

  2. The phenomenon of movement of water from soil to root xylem is mainly due to:
    a) Transpiration pull
    b) Root pressure
    c) Osmosis
    d) Diffusion
    Answer: c) Osmosis

  3. The major product of photosynthesis that is transported in plants is:
    a) Oxygen
    b) Glucose
    c) Carbon dioxide
    d) ATP
    Answer: b) Glucose

  4. The vascular cambium in plants is responsible for:
    a) Transporting water
    b) Secondary growth (increasing girth)
    c) Photosynthesis
    d) Seed formation
    Answer: b) Secondary growth (increasing girth)

  5. The pores on the stem of woody plants for gas exchange are called:
    a) Stomata
    b) Lenticles
    c) Root hairs
    d) Trichomes
    Answer: b) Lenticles

  6. The sugar transported in phloem is primarily:
    a) Sucrose
    b) Glucose
    c) Fructose
    d) Lactose
    Answer: a) Sucrose

  7. The process by which plant cells use oxygen to release energy from food is called:
    a) Photosynthesis
    b) Respiration
    c) Fermentation
    d) Transpiration
    Answer: b) Respiration

  8. The green pigment chlorophyll is located in:
    a) Mitochondria
    b) Chloroplasts
    c) Cytoplasm
    d) Nucleus
    Answer: b) Chloroplasts

  9. What causes the opening of stomata during the day?
    a) Low light
    b) Water entering guard cells
    c) High temperature
    d) Loss of water from guard cells
    Answer: b) Water entering guard cells

  10. Which of the following plant movements is caused by touch?
    a) Phototropism
    b) Geotropism
    c) Thigmotropism
    d) Hydrotropism
    Answer: c) Thigmotropism

  11. Which hormone causes the shedding of leaves?
    a) Auxin
    b) Ethylene
    c) Abscisic acid
    d) Gibberellin
    Answer: c) Abscisic acid

  12. Which process in plants requires energy?
    a) Diffusion
    b) Active transport
    c) Osmosis
    d) Evaporation
    Answer: b) Active transport

  13. The process by which plants lose excess water in liquid form through hydathodes is:
    a) Transpiration
    b) Guttation
    c) Respiration
    d) Evaporation
    Answer: b) Guttation

  14. The energy from sunlight is captured by:
    a) Chlorophyll
    b) Xylem
    c) Phloem
    d) Mitochondria
    Answer: a) Chlorophyll

  15. Which tissue is responsible for transporting manufactured food in plants?
    a) Xylem
    b) Phloem
    c) Parenchyma
    d) Collenchyma
    Answer: b) Phloem

  16. Which hormone is used commercially to ripen fruits?
    a) Auxin
    b) Gibberellin
    c) Ethylene
    d) Cytokinin
    Answer: c) Ethylene

  17. Water moves upward in plants due to:
    a) Gravity
    b) Cohesion and adhesion of water molecules
    c) Osmosis only
    d) Photosynthesis
    Answer: b) Cohesion and adhesion of water molecules

  18. Which of the following is NOT true about stomata?
    a) They are involved in gas exchange
    b) They are found mainly on the upper surface of leaves
    c) Guard cells control their opening and closing
    d) They help in transpiration
    Answer: b) They are found mainly on the upper surface of leaves

  19. The vascular tissue responsible for transporting water and minerals is:
    a) Phloem
    b) Xylem
    c) Parenchyma
    d) Sclerenchyma
    Answer: b) Xylem

  20. The process of photosynthesis helps to:
    a) Provide energy to plants and release oxygen
    b) Provide energy to animals only
    c) Absorb oxygen and release carbon dioxide
    d) Store oxygen in the soil
    Answer: a) Provide energy to plants and release oxygen

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