Control & Coordination Important Questions Class 10 2026

The chapter Control and Coordination is one of the most important conceptual chapters in Class 10 Biology. It explains how living organisms respond to their surroundings and coordinate different activities to maintain balance and function effectively.

This topic helps students learn the nervous system, hormonal control, and plant movements, linking biology with real-world phenomena such as reflex actions, emotions, and growth patterns in plants.

These Control and Coordination Important Questions for Class 10 are designed to help you:

• Understand the mechanisms of the human nervous system and endocrine system.
• Revise key functions and processes in plants and animals.
• Practise diagram-based and reasoning questions commonly asked in board exams.

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Chapter 6 Control and Coordination : Important Questions

Q1. Auxin is a plant hormone that promotes cell elongation and is produced by the apical meristem. It inhibits the growth of lateral buds which are present at nodes (where leaves attach to the stem). As long as sufficient auxin is produced by the apical meristem, the lateral buds remain dormant.

A gardener wants the plants in the hedge that he is growing to become bushier with more branches. Which of the following should he do?

Answer: To make the plants in the hedge bushier with more branches, the gardener should encourage the growth of lateral buds. Since auxin inhibits the growth of lateral buds, the gardener should reduce the production or action of auxin at the apical meristem.

The gardener can do this by pruning the apical (tip) growth of the plants. By cutting back the main stem, the source of auxin production is reduced, which allows the lateral buds to become active and start growing. This process is known as apical dominance inhibition, which will result in a bushier plant with more branches.

Q2. During pollination, plants ensure that the pollen grain from a species germinates on the stigma of the same species.

Which of the following ensures this?

a. Chemotropism

b. Hydrotropism

c. Phototropism

d. geotropism

Answer: (a) Chemotropism

Explanation:

Chemotropism refers to the growth or movement of an organism or part of an organism in response to a chemical stimulus. In the context of pollination, the pollen grain produces chemical signals that attract it to the stigma of the same species. These chemical signals ensure that the pollen germinates on the stigma of a flower of the same species, promoting successful fertilization.

Q3. Sheila saw a snake and instantly jumped back. She then slowly moved away from the snake.

What is the difference between the two actions of instantly jumping and walking away?

Answer: The difference between Sheila instantly jumping back and slowly moving away from the snake lies in the type of response and the associated physiological processes:

‍Instantly jumping back: This action is an involuntary, reflexive response to the perceived danger (the snake). It is a quick, automatic reaction mediated by the nervous system, particularly the spinal cord, that occurs without conscious thought. This is often referred to as a startle reflex or escape reflex, which is a protective mechanism to quickly distance oneself from a threat.

‍Slowly moving away: This action is a voluntary, controlled movement that involves conscious thought. Sheila likely assessed the situation, decided to move away slowly to avoid further risk, and used her motor skills to walk. This movement is not an immediate reflex but rather a deliberate action based on her understanding of the situation.

In summary, the instant jump is a reflexive, unconscious reaction to danger, while slowly walking away is a voluntary, conscious action.

Q4. Hema bought some unripe tomatoes and left half of them in a brown paper bag and the other half in an open tray. After two days she noticed that the tomatoes in the paper bag had ripened, but the ones in the open tray had not.

(a) What hormone facilitated the ripening of tomatoes? 

(b) Why did the tomatoes in the paper bag ripen faster?

Answer: (a) The hormone that facilitated the ripening of tomatoes is ethylene. Ethylene is a plant hormone that plays a crucial role in the ripening of fruits. It triggers various biochemical processes that lead to the softening, color change, and development of flavor in fruits like tomatoes.

(b) The tomatoes in the paper bag ripened faster because the bag trapped the ethylene gas that the tomatoes produced. Ethylene is a volatile gas, and when it accumulates around the fruit, it accelerates the ripening process. In the open tray, the ethylene gas dispersed into the surrounding environment, and the concentration around the tomatoes remained lower, which slowed down the ripening process. By keeping the tomatoes in a confined space like the paper bag, the concentration of ethylene remained high, speeding up the ripening.

Q5. While on a roller coaster ride, Aditya noticed an increase in his heartbeat and his breathing. Which hormone is responsible for the changes in Aditya's body?

Answer: The hormone responsible for the increase in Aditya's heartbeat and breathing while on the roller coaster ride is adrenaline (also known as epinephrine).

Adrenaline is produced by the adrenal glands in response to stress or excitement (like during a roller coaster ride). It triggers the "fight or flight" response, which prepares the body for rapid action. Adrenaline increases the heart rate, dilates the airways to allow more oxygen to be taken in, and increases blood flow to muscles, among other effects. This results in the heightened heartbeat and faster breathing that Aditya experienced.

Q6. 'Plant growth regulators do not always promote growth.'

Cite one example in support of the above statement and mention the action of the same.

Answer: An example that supports the statement "Plant growth regulators do not always promote growth" is abscisic acid (ABA).

‍Action of Abscisic Acid (ABA):
Abscisic acid is a plant hormone that generally inhibits growth. It plays a crucial role in promoting dormancy in seeds and buds, and in responding to stress conditions such as drought. During water scarcity, ABA helps to close stomata to reduce water loss and inhibits growth processes to conserve energy and resources. Therefore, unlike other plant growth regulators that promote growth, ABA acts to slow down or inhibit growth under certain conditions, especially during environmental stress.

Q7. (a) As first line of defense, stress hormones are released in humans. As an equivalent, which hormone is most likely to be released as first line of defense in plants?

(b) There have been reports of plant hormones being found in animal bodies even when they are not synthesised by the animal. What can be the most common pathway of entry of such hormones in animals?

Answer: (a) The hormone most likely to be released as the first line of defense in plants is jasmonic acid.
Jasmonic acid is a plant hormone that is involved in the plant’s response to stress, such as herbivore attacks, pathogen infections, or physical damage. It acts as a signaling molecule, triggering the plant's defense mechanisms, including the production of defensive proteins and other compounds that help protect the plant from further damage. Just like stress hormones (like cortisol and adrenaline) in humans, jasmonic acid helps plants respond to stress by activating various defensive responses.

(b) The most common pathway of entry of plant hormones into animal bodies is through the food chain.
Plant hormones can enter animal bodies when animals consume plant materials such as fruits, vegetables, and other plant-based foods that contain these hormones. Once ingested, plant hormones may be absorbed into the bloodstream and can have physiological effects on the animal’s body, even though the animal does not synthesize them itself. This is a common way for plant hormones to influence animal biology, especially in cases where plant-derived substances have an effect on metabolism or development in animals.

Q8. (a) Name ONE plant hormone that controls directional growth.

(b) Plant hormones are also referred to as growth regulators and can be controlled by a number of stimuli.

Mention ONE point of difference between the functioning of animal growth hormones and plant growth regulators with respect to such control.

Answer: (a) One plant hormone that controls directional growth is auxin.
Auxin regulates phototropism (growth in response to light) and gravitropism (growth in response to gravity). It promotes cell elongation on the shaded side of the plant during phototropism, causing the plant to grow toward the light.

(b) One point of difference between the functioning of animal growth hormones and plant growth regulators with respect to control is:

• Animal growth hormones are typically controlled by the endocrine system and are released into the bloodstream to target specific organs or tissues.
• Plant growth regulators, on the other hand, are often controlled by environmental stimuli (such as light, gravity, or temperature) and can act locally or throughout the plant in response to these external factors.

In animals, the regulation is more systemic and involves feedback mechanisms, while in plants, the regulation can be more localized and responsive to immediate environmental changes.

Q9. Sapna suffers from a condition due to which her average blood sugar level is 174 mg/dL. The average blood sugar level in a healthy adult is <140 mg/dL.

Which of the following could be the cause of Sapna's condition?

a. insufficient production of thyroxine in her body

b. insufficient production of insulin in her body

c. excess production of thyroxine in her body

d. excess production of insulin in her body

Answer: (b) insufficient production of insulin in her body

Explanation: 

Insulin is a hormone produced by the pancreas that helps regulate blood sugar levels by allowing cells to take in glucose from the blood. If there is insufficient production of insulin (a condition known as diabetes), glucose cannot be effectively transported into cells, causing elevated blood sugar levels.

The other options:

• Insufficient production of thyroxine: This could lead to hypothyroidism, which affects metabolism but is not directly linked to elevated blood sugar levels.
• Excess production of thyroxine: This would typically cause hyperthyroidism, which can accelerate metabolism but does not directly cause high blood sugar levels.
• Excess production of insulin: This would lower blood sugar levels, not increase them.

Some important Questions for Control & Coordination Important Questions Class 10

Q1. what is a neuron and explain how information is transmitted.

Ans. A neuron is the functional unit of the nervous system. It has dendrites, a cell body (cyton) and a long axon.

• Dendrites receive signals from receptors.
• The cell body processes the information.
• The axon carries impulse to nerve endings.
• At the synapse, electrical impulse triggers release of neurotransmitters which cross the gap and start a new impulse in the next neuron.

This chain of transmission helps in coordination of body activities.

Q2. What is reflex action? Explain its pathway.

Ans. Reflex action is a sudden, involuntary response to a stimulus. Example: withdrawing hand from flame.

Pathway (Reflex Arc):

1. Receptor detects stimulus.
2. Sensory neuron → spinal cord.
3. The relay neuron connects to the motor neuron.
4. Motor neuron → effector (muscle).
5. Muscle contracts → action done.

Reflexes are protective and prevent injury.

Q3. Differentiate between voluntary, involuntary and reflex actions with examples.

Ans. 

• Voluntary: Done consciously, controlled by the brain (e.g., writing, walking).
• Involuntary: Occur without control, managed by medulla/hindbrain (e.g., heartbeat, digestion).
• Reflex: Sudden response without thinking, spinal cord controls (e.g., knee jerk, blinking).

Thus, actions differ by control centre, speed and need of thinking.

Q4. Explain structure and functions of the human brain.

Ans. The brain is the main coordinating centre of the body, protected in the skull and cushioned by fluid.

• Forebrain: controls voluntary actions, thoughts, memory, emotions; also hunger/thirst.
• Midbrain: controls reflexes of eyes and ears.
• Hindbrain: Cerebellum: balance and posture.

Medulla oblongata: involuntary actions (breathing, heartbeat).

Q5. How are the brain and spinal cord protected?

Ans.  Here are the answers of the following:

• The brain is enclosed in a bony skull. It is surrounded by meninges and cushioned in cerebrospinal fluid (CSF) which absorbs shocks.
• The spinal cord lies in the vertebral column (backbone), also cushioned by CSF.

This protection prevents damage from injuries.

Q6. What happens at the synapse between two neurons?

Ans. The synapse is a small gap between the axon terminal of one neuron and the dendrite of next.

• When impulse reaches the axon end, neurotransmitters are released.
• These chemicals cross synapses and generate a new impulse in the next neuron.

Thus, synapse ensures one-way transmission of information.

Q7. Describe an experiment to demonstrate phototropism.

Ans. here are the experiment to demonstrate phototropism:

• Take a flask with water, place germinated seedlings on wire mesh.
• Keep the flask in a cardboard box open on one side.
• After 3–4 days, shoots bend towards light and roots away.

Q8. How do auxins help in bending of shoots towards light?

Ans. Auxin is a plant hormone produced at shoot tips.

• When light falls on one side, auxin shifts to the shady side.
• Cells on the shady side elongate faster → shoot bends towards light.

This helps plants capture maximum sunlight for photosynthesis.

Q9. Differentiate between tropic and nastic movements in plants with examples.

Ans. here are the differentiate answers:

• Tropic movement: Directional, depends on stimulus direction. Example: shoot bending towards light (phototropism).
• Nastic movement: Non-directional, depends on stimulus but not its direction. Example: folding of Mimosa leaves when touched.

Q10. Explain geotropism and hydrotropism in plants with activity.

Ans. Here are the explanation: 

• Geotropism: Roots grow towards gravity (positive), shoots against gravity (negative).
• Hydrotropism: Roots grow towards water.
• Activity: Plant seedling near a water source (clay pot). Roots bend towards the pot → shows positive hydrotropism.
  
  

Q11. What are plant hormones? Name and explain the role of four.

Ans. Plant hormones regulate growth and responses:

• Auxin: Cell elongation, phototropism.
• Gibberellin: Stem elongation, seed germination.
• Cytokinin: Cell division, delays aging.
• Ethylene: Fruit ripening.
• Abscisic Acid (ABA): Inhibits growth, causes wilting, seed dormancy.

Q12. How do tendrils coil around support?

Ans. Tendrils are touch-sensitive.

• When a tendril touches support, auxin moves to the opposite side.
• Cells on the free side grow faster → tendril bends around support.

This helps plants climb and get sunlight.

Q13. How does chemical coordination occur in animals?

Ans.  Animals have endocrine glands which release hormones into blood.

• Hormones act on specific organs called target organs.
• Example: Insulin regulates sugar, Adrenaline prepares the body for emergencies.

Thus, hormones provide slow but long-lasting control.

Q14. Explain the role of Adrenaline in emergency situations.

Ans. Adrenaline is secreted by adrenal glands during stress or excitement.

• Increases heartbeat & breathing.
• Diverts blood to muscles.
• Raises glucose level for energy.

Thus, the body is prepared for “fight or flight”.

Q15. Why is use of iodised salt advised?

Ans. Thyroid gland needs iodine to produce thyroxine hormone.

• Thyroxine regulates metabolism of carbohydrates, fats and proteins.
• Lack of iodine → low thyroxine → disease goitre (neck swelling).

So, iodised salt prevents goitre.

Q16. Explain the role of pituitary gland in humans.

Ans. The pituitary gland is called the “master gland”.

• It controls other endocrine glands.
• Secretes growth hormone which regulates overall growth.
• Also regulates thyroid, adrenal and reproductive glands.

Thus, pituitary maintains hormonal balance.

Q17. Compare the nervous system and endocrine system.

Ans. Both coordinate body functions together.

• Nervous system: Uses electrical impulses, very fast, short-lived, acts via neurons.
• Endocrine system: Uses hormones in blood, slower but long-lasting, widespread effect.

Q18. What is the feedback mechanism in hormones? Explain with examples.

Ans. Feedback mechanism ensures the correct amount of hormone secretion.
Here are the example:

• When blood sugar rises, the pancreas secretes insulin → lowers sugar.
• When sugar normalises, insulin secretion stops.

Thus, feedback prevents excess or deficiency.

Q19. What happens if the spinal cord is damaged?

Ans. The spinal cord carries impulses between the brain and body and controls reflexes.
Damage may cause:

• Loss of reflex actions.
• Paralysis of body parts below injury.
• Disturbed coordination.

Thus, the spinal cord is vital for movement and protection.

Q20. How does cerebellum help in coordination?

Ans. Cerebellum, part of hindbrain, controls:

• Balance and posture.
• Precision of voluntary actions like walking straight, cycling, writing.

If the cerebellum is damaged, movements become unbalanced and jerky.

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Video Lecture: Must-watch for Quick Revision

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Extra Practice Questions – Test your skills!

Q1. Draw a neat diagram of a neuron and label its parts. Write the function of each part.

Q2. Explain with the help of a diagram how the reflex arc works when you accidentally touch a hot object.

Q3. What is phototropism? Describe an activity to demonstrate it.

Q4. Which part of the brain helps in maintaining posture and balance of the body? Explain its role with examples.

Q5. Which hormone helps in ripening of fruits? Write any two observations that prove its action.

Q6. Why is adrenaline called the “fight or flight” hormone? Give situations where it is useful.

Q7. How does insulin control the sugar level in our body? What happens if insulin is not secreted properly?

Q8. How do tendrils of pea plants find support and coil around them? Explain the process.

Q9. Name the three main parts of the human brain. Write one function of each.

Q10. Name any two plant hormones that promote growth and two that inhibit growth. Give examples of each.

How to Ace These Class 10 Control and Coordination Important Questions

Scoring full marks in this chapter requires a clear understanding of biological processes and proper use of terminology. Follow these steps for effective preparation:

Step 1: Begin with NCERT Reading

Read the NCERT chapter carefully to understand the working of the human nervous system, structure of neurons, reflex arcs, and coordination through hormones.

Step 2: Learn the Human Nervous System

Understand the three parts of the human nervous system – central, peripheral, and autonomic. Study how the brain, spinal cord, and nerves coordinate voluntary and involuntary actions. Memorize the functions of different brain parts such as the cerebrum, cerebellum, and medulla oblongata.

Step 3: Practise Diagrams

Draw and label diagrams of the human brain, reflex arc, and neuron. These are frequently asked in exams and carry marks for labeling and clarity.

Step 4: Study Coordination in Plants

Understand how plants respond to stimuli such as light, gravity, and touch. Learn the difference between tropic movements (directional) and nastic movements (non-directional). Revise examples like phototropism, geotropism, and thigmotropism.

Step 5: Revise the Endocrine System

Focus on important glands such as the pituitary, thyroid, adrenal, pancreas, and sex glands. Learn the hormones they secrete and their roles in growth, metabolism, and reproduction. Questions on hormone function are common in CBSE exams.

Step 6: Link with Real-Life Applications

Understand practical examples such as reflexes in daily life, the role of adrenaline in emergencies, and how plants grow toward sunlight. Relating theory to real-life phenomena improves conceptual retention.

Step 7: Practise Case-Based and Assertion Questions

Since CBSE now includes competency-based questions, solving application-oriented and assertion-reason questions will help you strengthen your analytical skills.

Benefits of Practising These Class 10 Control and Coordination Questions

Here are the benefits of practising these class 10 control and coordination questions and with answers that can help you:

• Clear Conceptual Understanding: Strengthens your grasp of how organisms coordinate and respond.
• Better Answer Presentation: Improves diagram and labeling accuracy for higher marks.
• Enhanced Recall: Helps remember complex biological terms and processes easily.
• Exam-Focused Preparation: Includes questions aligned with CBSE board patterns.
• Confidence Building: Reduces confusion between similar topics such as plant and animal coordination
  

FAQs

Q1. How many marks are usually allotted to the Control and Coordination chapter in Class 10 Science exams?

Ans. This chapter generally carries around 4 to 6 marks and often includes one diagram-based question.

Q2. Which topics are most important for the board exam?

Ans. The structure of the brain, reflex arc, neuron diagram, endocrine glands and their functions, and types of plant movements are the most important.

Q3. How can I memorise hormone names and functions effectively?

Ans. Create a table listing each gland, its hormone, and its function. Use simple associations, for example, adrenaline for emergencies and insulin for sugar regulation.

Q4. Are diagrams compulsory in long answers?

Ans. They are not compulsory in every question but are highly recommended whenever relevant. Well-labeled diagrams often help secure full marks.

Q5. How can I improve my explanation in long answers?

Ans. Use key biological terms and maintain logical flow. Start with definitions, add examples, and end with concise conclusions.