Chapter 1 – Control and co-ordination in living organisms Q&A

Want to understand this chapter step by step before your exam? The topic Control and Coordination in Living Organisms is very important for your WBBSE Class 10 exam. This page gives you important questions and answers in clear and easy English. These questions are based on important topics and exam patterns. This will help you learn easily, revise faster, and score good marks in your exam.

Content Structure

• 1. Multiple choice questions and answers (MCQs)
• 2. Very short-type questions and answers
  • 2A. Fill in the blanks
  • 2B. True or false
  • 2C. Match the column
  • 2D. Single word questions and answers
• 3. Short-type questions and answers
• 4. Long-type questions and answers

1. Multiple choice questions and answers (MCQs)

[Each question carries 1 mark] 

1. The growth of a plant part in response to light is called—
(a) Hydrotropism
(b) Phototropism
(c) Thigmotropism
(d) Chemotropism

Ans: (b) Phototropism

2. Stimulus is a type of –
(a) Sensation
(b) Observation
(c) Response
(d) Energy

Ans: (d) Energy

3. Blooming of lotus in daylight is—
(a) Tactic movement
(b) Tropic movement
(c) Nastic movement
(d) Movement of variation

Ans: (c) Nastic movement

4. The reaction caused by a stimulus is called—
(a) Response
(b) Sensitivity
(c) Receptor
(d) Effector

Ans: (a) Response

5. The plant that clearly shows sensitivity is—
(a) Lotus
(b) Touch-me-not  plant
(c) Vasak
(d) Water hyacinth

Ans: (b) Touch-me-not plant

6. Nastic movement caused by chemicals is—
(a) Chemonastic movement
(b) Thermonastic movement
(c) Nyctinastic movement
(d) Seismonastic movement

Ans: (a) Chemonastic movement

7. Sundew plant bending to trap insects is—
(a) Thigmonasty
(b) Chemonasty
(c) Photonasty
(d) Thermonasty

Ans: (a) Thigmonasty

8. Which is not an external stimulus?
(a) Poison
(b) Hormone
(c) Heat
(d) Touch

Ans: (b) Hormone

9. Movement of variation is caused by—
(a) Variation in turgor pressure within cells
(b) Variation in temperature within cells
(c) Increase in number of vacuoles inside the cells
(d) Increase in number of cells

Ans: (a) Variation in turgor pressure within cells

10. Lateral leaflets of telegraph plant show—
(a) Photonastic movement
(b) Geotropic movement
(c) Movement of variation
(d) Seismonastic movement

Ans: (c) Movement of variation

11. Crescograph was used by—
(a) Jagadish Chandra Bose
(b) Charles Newton
(c) Prafulla Chandra Roy
(d) Satyendra Nath Bose

Ans: (a) Jagadish Chandra Bose

12. Tropic movement controlled by sunlight—
(a) Hydrotropic movement
(b) Geotropic movement
(c) Phototropic movement
(d) Chemotropic movement

Ans: (c) Phototropic movement

13. Some flowers open after sunrise and close after sunset. This is –
(a) Photonasty
(b) Thermonasty
(c)  Seismonasty
(d) Chemonasty

Ans: (a) Photonasty

14. Movement of whole body due to stimulus—
(a) Nastic movement
(b) Movement of variation
(c) Tactic movement
(d) Tropic movement

Ans: (c) Tactic movement

15. Movement controlled by direction of water—
(a) Phototropic movement
(b) Hydrotropic movement
(c) Geotropic movement
(d) Hydrotactic movement

Ans: (b) Hydrotropic movement

16. Movement caused by change in turgor pressure is—
(a) Nastic movement
(b) Chemotactic movement
(c) Tactic movement
(d) Tropic movement

Ans: (a) Nastic movement

17. The organism, which demonstrates locomotion, is-
(a) Volvox
(b) Mucor
(c) Telegraph plant
(d) Mimasa pudica

Ans: (a) Volvox

18. Which of the following performs locomotion by flagella?
(a) Chlamydomonas
(b) Spermatozoa of moss
(c) Spermatozoa of fern
(d) All of these

Ans: (d) All of these

19. Which plant hormone stimulates stem elongation?
(a) ABA
(b) Gibberellins
(c) Cytokinins
(d) Ethylene

Ans: (b) Gibberellins

20. The growth of roots towards water is known as—
(a) Positive hydrotropism
(b) Negative hydrotropism
(c) Positive geotropism
(d) Positive phototropism

Ans: (a) Positive hydrotropism

21. Roots growing downward due to gravity—
(a) Positive geotropism
(b) Negative geotropism
(c) Positive phototropism
(d) Negative phototropism

Ans: (a) Positive geotropism

22. Pollen tube growth toward the ovule is an example of—
(a) Phototropism
(b) Chemotropism
(c) Geotropism
(d) Thigmotropism

Ans: (b) Chemotropism

23. Fruit fall and leaf fall happen because of which hormone?
(a) Ethylene
(b) Cytokinin
(c) ABA
(d) Auxin

Ans: (c) ABA

24. Plant movement caused by chemicals is called—
(a) Nyctinasty
(b) Chemonasty
(c) Thermonasty
(d) Seismonasty

Ans: (b) Chemonasty

25. The movement of roots toward water is called—
(a) Geotropism
(b) Hydrotropism
(c) Phototropism
(d) Chemotropism

Ans: (b) Hydrotropism

26. When a plant moves towards a stimulus, it is called—
(a) Tropic movement
(b) Nastic movement
(c) Amoeboid movement
(d) None of these

Ans: (a) Tropic movement

27. Plant movement toward light is called—
(a) Geotropism
(b) Phototropism
(c) Hydrotropism
(d) Seismonasty

Ans: (b) Phototropism

2. Very short-type questions and answers

[Each question carries 1 mark]

2A. Fill in the blanks

1. Movement of an organism in response to the intensity of stimulus is called ______________.(Nastic movement)
2. Movement of organisms from one place to another is called ________.(Locomotion)
3. The name of movement found in Mimosa Pudica is __________________.(Seismonasty)
4. The growth of a plant shoot towards light is called ________.(Phototropism)
5. In ______________ movement the pollen tube moves toward the ovum.(Chemotropism)
6. Hormone is type of _______________ stimulus.(internal)
7. Leaves of touch-me-not plant respond to _______________.(touch)
8. The overall displacement or ____________ is found in unicellular plants or plant germ cells.(locomotion)
9. Negative ____________ movement is noticed in the pneumatophores of halophytes.(geotropic)
10. Tropic movement stimulated by gravity is called ______________ movement.(geotropic)
11. Other name of tropic movement is ______________ movement.(curvature)
12. In an alga named ___________, we see phototactic movement. (Chlamydomonas)
13. Auxin hormone controls ____________ movement.(phototropic)
14. Tropic movement is controlled by the ______________ of the stimulus.(direction)
15. Phototropism is also known as _______________.(heliotropism)
16. Gravity of the earth acts as the stimulus for _______________ movement.(geotropic)
17. The change in the environment that causes a response is called a ________.(Stimulus)
18. Roots growing towards water show ________.(Positive hydrotropism)
19. Auxin is the plant hormone responsible for ________ of cells.(Elongation)

2B. True or false

1. Sir Jagadish Chandra Bose worked on telegraph plant. (True)
2. Chemonasty occurs according to the direction of the stimulus. (False)
3. Photonasty is seen in evening primrose flower. (True)
4. Tropic movement is a five types. (True)
5. Age of plants can be determined by crescograph. (False)
6. Positive hydrotropic movement is noticed in shoot of plants. (False)
7. Photonastic movement is seen in sunflower and lotus. (False)
8. Phototactic and phototropic movements are the same. (False)
9. Tropic movement is the movement of growth in plants. (True)
10. Tactic movement is a type of growth movement. (False)
11. Auxin helps plants bend toward light. (True)
12. Hydrotropism is movement toward water. (True)
13. Nastic movements are fast and reversible. (True)

2C. Match the column

1. Match the following items in List I with correct items in List II.

A	B
1. Transverse phototropism	A. Pneumatophore
2. Negative geotropism	B. Leaf
3. Positive phototropism	C. Tap root
4. Negative phototropism	D. Chlamydomonas
5. Chemonastic movement	E. Flower
6. Phototaxis	F. Stem
	G. Sundew plant

Ans:

A	B
1. Transverse phototropism	B. Leaf
2. Negative geotropism	F. Stem
3. Positive phototropism	E. Flower
4. Negative phototropism	C. Tap root
5. Chemonastic movement	G. Sundew plant
6. Phototaxis	D. Chlamydomonas

2. Match the following items in List I with correct items in List II.

A	B
1. Stem	A. Positive geotropic
2. Auxin	B. External stimulus
3. Heat	C. Seismonasty
4. Volvox	D. Internal stimulus
5. Roots	E. Negative geotropic
6. Touch-me-not	F. Nyctinasty
	G. Phototactic

Ans:

A	B
1. Stem	E. Negative geotropic
2. Auxin	D. Internal stimulus
3. Heat	F. Nyctinasty
4. Volvox	G. Phototactic
5. Roots	A. Positive geotropic
6. Touch-me-not	C. Seismonasty

3. Match the following items in List I with correct items in List II.

A	B
1. Auxin	A. Closing of leaves
2. Cytokinin	B. Growth hormone
3. Seismonasty	C. Delayed ageing
4. Hydrotropism	D. Movement due to water
5. Phototropism	E. Bending toward light
6. Thigmotropism	F. Movement due to touch

Ans:

A	B
1. Auxin	B. Growth hormone
2. Cytokinin	C. Delayed ageing
3. Seismonasty	A. Closing of leaves
4. Hydrotropism	D. Movement due to water
5. Phototropism	E. Bending toward light
6. Thigmotropism	F. Movement due to touch

2D. Single word or single sentence questions and answers

1. What is the name of the movement involved in the opening of Tulip flower?
Ans: Thermonasty

2. How do you denote the movement of different parts of a plant, fixed to the soil?
Ans: Movement of curvature

3. How do you designate any change in environment or any substance that creates a response in an organism?
Ans: Stimulus

4. Give an example of nastic movement?
Ans: Folding of leaves in Mimosa pudica when touched.

5. Mention the types of stimuli based on their source.
Ans: Based on their sources stimuli are of two types – external stimuli and internal stimuli.

6. Name the type of movement which depends on intensity of stimulus?
Ans: Nastic movement

7. In Sundew when an insect comes in contact with leaf, the hairs move towards the insect. Name the movement.
Ans: Chemonasty

8. “The leaflets of a sensitive plant become folded when touched” -What type of movement is this?
Ans: Seismonasty

9. Which hormone is responsible for tropic movement?
Ans: Auxin

10. In which plant do you find negative geotropic movement?
Ans: Mangrove plants

11. Give example of an external stimulus.
Ans: Light

12. Mention one sign of response by any organism.
Ans: Movement.

13. Give example of positive phototropism.
Ans: Movement of stem of plant towards the source of light is an example of positive phototropism.

14. Mention the scientific name of telegraph plant.
Ans: Desmodium gyrans

15. Mention the scientific name of touch-me-not plant.
Ans: Mimosa pudica

16. Name the hormone responsible for apical dominance.
Ans: Auxin.

17. Name any two plant growth promoters.
Ans: Auxins and Gibberellins.

18. Which plant hormone causes ripening of fruits?
Ans: Ethylene.

19. Which plant hormone induces dormancy in seeds?
Ans: Abscisic acid (ABA).

3. Short-type questions and answers

[Each question carries 2 marks]

1. What is tropic movement?
Ans: Tropic movement is the growth movement of a plant part towards or away from a stimulus such as light, gravity, or water. Ex: Bending of stem toward light.

2. What is movement?
Ans: Movement is the change in position of any part of a living organism. Example: The bending of a leaf toward sunlight or the closing of a flower at night.

3. What do you mean by nastic movement?
Ans: Nastic movement is the movement of plant parts caused by the intensity of a stimulus like light, temperature, or touch and not its direction. Ex: Folding of Mimosa leaves when touched.

4. Define tactic movement.
Ans: Tactic movement is the movement of a whole plant cell or organism from one place to another in response to a stimulus like light, temperature, or chemicals. Ex: Chlamydomonas swims toward light.

5. What is phototropism? Give an example.
Ans: Phototropism means a plant bends toward light. Example: A sunflower turns its face toward the sun from morning to evening.

6. What is chemonasty?
Ans: Chemonasty is a nastic movement caused by chemical substances. Ex: Sundew bends its tentacles toward trapped insects.

7. What is hydrotropism? Describe an example.
Ans: Hydrotropism means plants grow towards water. Example: Roots always grow in the direction where water is present.

8. What is thigmotropism? Give an example.
Ans: Thigmotropism means plants respond to touch. Example: Tendrils curl around any stick or support they touch.

9. What is meant by “apical dominance”? Which hormone is responsible?
Ans: Apical dominance means the main stem of a plant grows faster and stronger than the side branches.
The hormone that controls this is auxin.

10. Define chemotropism with an example.
Ans: Chemotropism means plants respond to chemicals. Example: The pollen tube grows towards the chemical signals from the ovule.

11. What causes nastic movement in Mimosa pudica?
Ans: The leaves fold because the cells at the base of the leaf lose water very quickly.

12. How does the telegraph plant (Desmodium gyrans) show movement?
Ans: The small leaves of the telegraph plant move up and down again and again. This happens because the amount of water inside the leaf cells keeps changing. So the leaves look like they are “dancing.”

13. How do plants sense environmental changes without nerves or muscles?
Ans: Plants can feel changes around them by changing how they grow or by moving water in and out of their cells. They can feel light, touch, water, gravity, and even some chemicals, and they react in their own way.

14. How do roots sense gravity?
Ans: Roots sense gravity using special cells called statocytes, which help the roots understand which direction is down, so the roots always grow deeper into the soil.

15. How do carnivorous plants show sensitivity?
Ans: Carnivorous plants like Sundew and Venus flytrap have tiny hair-like sensors on their leaves when an insect touches these sensors, the leaves quickly close and trap the insect inside.

4. Long-type questions and answers

[Each question carries 5 marks]

1. (a) Define locomotion.
(b) Name a plant in which locomotion is observed and an animal in which locomotion is not observed.
Ans: (a) Definition: Locomotion is the movement of an entire organism from one place to another in response to internal or external stimuli.
It helps living beings search for food, light, water, and better living conditions.

(b) Examples:

• Plant showing locomotion: Chlamydomonas or Volvox (they swim freely in water using flagella).
• Animal without locomotion: Sponge or Coral (these remain fixed at one place throughout their life).

Explanation:
In most plants, the body is fixed in one place, so locomotion is absent. However, some lower aquatic plants can move from one place to another.
In animals, locomotion is common, but a few like sponges are sessile (attached to a surface).

2. Describe different types of nastic movements with one example from each.
Ans: Nastic movements are movements in plants caused by the intensity of a stimulus like light, temperature, touch, or chemicals — but not by its direction.
These movements usually occur in mature parts of plants due to changes in turgor pressure.

Types of Nastic Movements:

(i) Photonasty (Light):

• Caused by change in light intensity.
• Example: Lotus and Water lily open in sunlight and close at night.
• This helps the plant carry out photosynthesis during the day.

(ii) Thermonasty (Temperature):

• Caused by change in temperature.
• Example: Tulip and Crocus flowers open in warmth and close in cold.
• This protects the inner parts of flowers from temperature changes.

(iii) Chemonasty (Chemicals):

• Caused by chemical substances.
• Example: Sundew (Drosera) bends its sticky hairs toward the insect when it senses nitrogen compounds.

(iv) Seismonasty (Touch or Shock):

• Caused by mechanical stimuli like touch or vibration.
• Example: Mimosa pudica folds its leaves when touched.
• This happens because water leaves the cells in the pulvinus (leaf base), reducing turgor pressure.

3. What is tropic movements? Explain two types of tropic (phototropic and geotrotropic) movements in plants?
Ans: Tropic movements are growth movements of plant organs in response to directional stimuli like light, gravity, or water.
They can be positive (toward the stimulus) or negative (away from it).

 (a) Phototropic Movement (Light Response):

• Stimulus: Light
• Definition: Movement of plant organs in response to the direction of light.
• Example: Stem grows toward light (positive phototropism); root grows away from light (negative phototropism).
• Explanation: The plant hormone Auxin moves to the shaded side of the stem, causing faster growth on that side and bending the stem toward the light source.

Experiment:

• Place a potted plant near a window.
• After a few days, the stem bends toward sunlight — showing positive phototropism.

 (b) Geotropic Movement (Gravity Response):

• Stimulus: Gravity
• Definition: Movement of plant parts in response to the pull of gravity.
• Example:
  • Roots grow downward → Positive geotropism
  • Shoots grow upward → Negative geotropism
• Explanation: Gravity affects the distribution of Auxin hormone, causing the lower side of the root or shoot to grow differently and bend accordingly.

Experiment:

• Place germinating seeds horizontally.
• Roots bend downward and shoots bend upward, proving geotropism.

4. Briefly describe the different types of tropic movements in plant.
Ans: Types of Tropic Movements:

• Phototropism: Movement toward light (Stem → positive, Root → negative).
• Geotropism: Movement toward gravity (Root → positive, Stem → negative).
• Hydrotropism: Movement toward water (Root → positive).
• Thigmotropism: Movement due to touch (Tendrils of climbers like pea plants coil around support).
• Chemotropism: Movement due to chemicals (Pollen tube grows toward ovum in flower).

5. Describe an experiment to show that plant organs move towards light.
Ans: Phototropism is the movement of a plant part in response to light, and it can be observed by placing a potted plant seedling near a window where light enters from only one direction.
The plant is watered regularly and kept under observation for a few days. After some time, it can be seen that the stem bends toward the window, where the light is coming from. This shows that the stem grows toward light, which means the plant exhibits positive phototropism.

6. Discuss briefly the hydrotropic movement in plants.
Ans: Hydrotropism is the movement of plant organs, especially roots, in response to water.

Explanation:

• Stimulus: Water
• Positive hydrotropism: Roots grow toward the water source.
• Negative hydrotropism: Shoots grow away from water.

Experiment:

• Keep germinating seeds on a sieve containing moist sawdust.
• Roots pass through holes and bend toward moist areas instead of growing straight down.
• This shows positive hydrotropism.

Importance:
It helps roots absorb water and minerals effectively, which is essential for plant survival.

7. Distinguish between Tactic and Nastic movements.
Ans: 

Feature	Tactic Movement	Nastic Movement
Meaning	Movement of whole organism or cell.	Movement of plant parts.
Stimulus Type	Directional (light, chemical, temperature).	Non-directional (intensity of stimulus).
Nature	Locomotion-type movement.	Turgor-based movement.
Examples	Chlamydomonas swims toward light.	Mimosa pudica folds when touched.

8. Explain geotropism with an example.
Ans: Geotropism is how plants react to the Earth’s pulling force, which is gravity.

It’s very easy to remember:

• The roots always grow down toward the center of the Earth, following gravity. This is called positive geotropism.
• The shoots (the stems and leaves) always grow up, away from the ground and against gravity. This is called negative geotropism.

9. Describe different types of plant tropisms with examples.
Ans:

1. Phototropism – movement due to light.
   • Shoots bend towards light.
2. Geotropism – movement due to gravity.
   • Roots grow downward (positive geotropism).
3. Hydrotropism – response to water.
   • Roots grow towards water.
4. Thigmotropism – response to touch.
   • Tendrils coil around support.
5. Chemotropism – response to chemicals.
   • Pollen tube grows towards ovule.

These movements help the plant respond to environmental changes.

10. Describe the five major plant hormones and their functions.
Ans:

1. Auxins
   • Cell elongation
   • Phototropism, geotropism
   • Apical dominance
2. Gibberellins
   • Stem elongation
   • Breaking seed dormancy
   • Fruit growth
3. Cytokinins
   • Cell division
   • Delay ageing of leaves
   • Promote shoot formation
4. Ethylene
   • Fruit ripening
   • Leaf and fruit fall (abscission)
5. Abscisic Acid (ABA)
   • Growth inhibition
   • Stomatal closure
   • Seed dormancy

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