This MCQ module is based on: Control and Coordination – NCERT Exercises
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Control and Coordination – NCERT Exercises
🎓 Class 10
Science
CBSE
Theory
Ch 6 — Control and Coordination
⏱ ~16 min
🌐 Language: [gtranslate]
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Chapter Summary
- Living bodies sense changes (stimuli) and respond through control and coordination systems.
- Animals use two systems: the nervous system for rapid electrical signals and the endocrine system for slower chemical signals.
- The neuron is the structural and functional unit of the nervous system — dendrite, cell body and axon. Impulses cross from one neuron to the next through a synapse using neurotransmitters.
- A reflex arc (Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector) produces quick automatic responses via the spinal cord.
- The brain has three regions: fore-brain (cerebrum — thinking, voluntary action), mid-brain (relay, eye/ear reflexes) and hind-brain (cerebellum — balance; medulla — heart-beat, breathing; pons).
- Plants respond to stimuli through tropisms (directional growth) and nastic movements (non-directional).
- Plant hormones: auxin, gibberellin, cytokinin, abscisic acid and ethylene.
- Animal endocrine glands: pituitary (master), thyroid, adrenal, pancreas, testes, ovaries — each releasing specific hormones into blood.
- Hormone levels are balanced by feedback mechanisms (e.g. blood sugar / insulin loop).
Key Terms
Stimulus
A change in environment that a body can detect.
Receptor
Specialised cell that detects a stimulus.
Effector
Muscle or gland that carries out a response.
Neuron
Cell that transmits nerve impulses.
Synapse
Gap between two neurons; crossed chemically.
Reflex Arc
Short pathway via spinal cord for quick response.
CNS
Brain + spinal cord; processes information.
PNS
Cranial and spinal nerves outside CNS.
Cerebrum
Fore-brain; thinking, memory, voluntary action.
Cerebellum
Hind-brain; posture and balance.
Medulla
Hind-brain; heart-beat, breathing.
Tropism
Directional plant growth towards/away from a stimulus.
Phototropism
Growth response to light.
Geotropism
Growth response to gravity.
Hydrotropism
Growth response to water.
Chemotropism
Growth response to chemicals.
Auxin
Plant hormone — cell elongation, tropisms.
Gibberellin
Plant hormone — stem growth.
Cytokinin
Plant hormone — cell division.
Abscisic Acid
Plant hormone — dormancy, wilting.
Ethylene
Gaseous plant hormone — fruit ripening.
Pituitary
Master endocrine gland; growth hormone.
Thyroxine
Thyroid hormone; needs iodine.
Adrenaline
Fight-or-flight hormone from adrenals.
Insulin
Pancreas hormone; lowers blood sugar.
Feedback
Self-regulating control of hormone levels.
NCERT Exercise Questions (Solved)
Q1Which part of the brain maintains posture and equilibrium of the body?
Answer: The cerebellum, which is a part of the hind-brain, maintains posture and body balance. Activities such as riding a bicycle, walking on a narrow ledge or picking up a pencil all depend on it.
Q2How do we detect the smell of an agarbatti (incense stick)?
Answer: Volatile molecules released from the agarbatti enter the nasal cavity and dissolve in the moist lining. They stimulate olfactory receptors — specialised sensory cells in the nose. These receptors generate nerve impulses that travel via the olfactory nerve to the fore-brain, where a dedicated region interprets the signal as a particular smell.
Q3What is the role of the brain in reflex action?
Answer: The main job of generating a reflex is done by the spinal cord, not the brain. However, the brain is still informed — the same impulse that enters the spinal cord is forwarded up to the brain a fraction of a second later, and this is why we feel the stimulus (for example, the heat of a flame). So the brain's role in reflex action is mainly perception and memory, not the immediate response.
Q4What are plant hormones?
Answer: Plant hormones (phytohormones) are chemical compounds produced in small amounts by plant tissues — usually the tips of shoots, roots and young leaves — that move to other parts of the plant and regulate growth, development and responses. Examples: auxin (cell elongation, phototropism), gibberellin (stem growth), cytokinin (cell division), abscisic acid (dormancy, wilting) and ethylene (fruit ripening).
Q5How is the movement of leaves of the sensitive plant (Mimosa pudica) different from the movement of a shoot towards light?
Answer:
| Mimosa leaf folding | Shoot bending to light |
|---|---|
| Very quick (within seconds) | Slow (takes hours or days) |
| Non-directional (nastic) | Directional (tropic) |
| Due to water-pressure changes in pulvini | Due to differential growth caused by auxin |
| Not a growth movement — reversible | A permanent growth movement |
Q6Give an example of a plant hormone that promotes growth.
Answer: Auxin promotes cell elongation at the shoot tip. Gibberellin promotes stem elongation, and cytokinin promotes cell division. All three are growth-promoting hormones.
Q7How do auxins promote the growth of a tendril around a support?
Answer: When a tendril touches a support, the side that is in contact with the support experiences less growth because auxin migrates to the opposite side (the free side). The free side accumulates more auxin and its cells elongate faster. This unequal growth makes the tendril curl around and grip the support.
Q8Design an experiment to demonstrate hydrotropism.
Procedure:
- Take a tray or wide container and fill it with soil.
- Sow a few germinating seeds (e.g. gram, wheat) in one corner.
- Place a small porous clay pot filled with water inside the soil, a few centimetres away from the seeds. Do not water the surrounding soil.
- After a week, carefully remove the soil and examine the direction in which the roots have grown.
Observation: The roots grow towards the porous pot where moisture is available, bending through the dry soil. This directional growth towards water is hydrotropism.
Q9How is chemical coordination achieved in animals?
Answer: In animals, chemical coordination is carried out by the endocrine system. Ductless glands — such as the pituitary, thyroid, adrenal, pancreas, testes and ovaries — secrete hormones directly into the blood. Blood carries these hormones to target organs, where they bind to specific receptors and change organ activity. A feedback mechanism keeps hormone levels balanced.
Q10Why is the use of iodised salt advisable?
Answer: Iodine is an essential component of thyroxine, the hormone released by the thyroid gland. Thyroxine regulates the rate at which the body uses energy (metabolism). In regions with iodine-poor soil, the diet contains very little iodine, which leads to goitre (enlargement of the thyroid) and other metabolic disorders. Iodised salt contains small amounts of potassium iodate / iodide to prevent iodine deficiency.
Q11How does our body respond when adrenaline is secreted into the blood?
Answer: Adrenaline, released by the adrenal glands during fear, anger, excitement or emergency, prepares the body for "fight or flight". Its effects include:
- Faster and stronger heart-beat — more blood is pumped out.
- Increased breathing rate — more oxygen is taken in.
- Blood is diverted away from the skin and digestive system towards the skeletal muscles.
- Pupils dilate and the liver releases glucose for quick energy.
Q12Why are some patients of diabetes treated by giving injections of insulin?
Answer: Insulin is the hormone that makes body cells absorb glucose from the blood, thereby lowering blood-sugar level. In patients with Type-1 diabetes, the pancreas cannot produce enough insulin, so their blood sugar stays dangerously high. Taking insulin tablets by mouth is not possible because the hormone, being a protein, would be digested in the stomach. To bypass digestion, insulin is injected directly into the body so it reaches the blood in active form and restores normal sugar control.
Q13Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
| Feature | Nervous coordination | Hormonal coordination |
|---|---|---|
| Nature of message | Electrical impulse | Chemical (hormone) |
| Transmission route | Along neurons (nerves) | Through blood |
| Speed | Very fast (milliseconds) | Slower (seconds to days) |
| Effect — how long it lasts | Short-lived | Generally longer-lasting |
| Target | Specific muscle or gland (localised) | All cells with the right receptor (can be widespread) |
| Control | Voluntary or reflex | Involuntary, by feedback mechanism |
| Example | Hand-withdrawal reflex on touching a hot object | Insulin controlling blood sugar; adrenaline in emergency |
The two systems complement each other — the nervous system handles immediate, targeted responses while the hormonal system manages longer-term, body-wide changes.
Frequently Asked Questions — NCERT Exercises & Intext Questions
How do I solve NCERT Class 10 Science Chapter 6 (Control and Coordination) exercise questions for the CBSE board exam?
Solve NCERT Chapter 6 — Control and Coordination — exercise questions by first reading the question carefully, writing down the given data, recalling the relevant concepts like nervous system, reflex action, brain, and applying them step by step. This Part 4 covers every intext and end-of-chapter exercise from the NCERT textbook. Write balanced equations, label diagrams clearly and show each step — CBSE Class 10 board examiners award step marks even if the final answer has a small slip. Practising these solutions strengthens conceptual clarity and builds speed for the board exam.
Are the NCERT intext questions from Control and Coordination important for the Class 10 board exam?
Yes, NCERT intext questions for Chapter 6 Control and Coordination are highly important for the CBSE Class 10 Science board exam. Many board questions are directly lifted or only slightly modified from these intext questions, and they test the foundational concepts — nervous system, reflex action, brain — that chapter-end questions build on. Attempt every intext question first, then move on to the exercises. This practice ensures complete NCERT coverage, which is the CBSE exam's primary source.
What types of questions from Control and Coordination are asked in the CBSE Class 10 Science board exam?
The CBSE Class 10 board paper asks a mix of question types from Control and Coordination: 1-mark MCQ and assertion-reason, 2-mark short answers, 3-mark explanations, 5-mark long answers with diagrams or derivations, and 4-mark competency-based / case-study questions. These test understanding of nervous system, reflex action, brain, hormones. Practising every NCERT exercise and intext question prepares you to answer all of these formats with confidence.
How many marks does Chapter 6 — Control and Coordination — carry in the Class 10 Science CBSE paper?
Chapter 6 — Control and Coordination — is part of the Class 10 Science syllabus and typically contributes 5–9 marks in the CBSE board paper, depending on the annual weightage. Questions are drawn from definitions, reasoning, numerical/descriptive problems and diagrams on topics like nervous system, reflex action, brain. Solving the NCERT exercises in this part is essential because CBSE directly references NCERT for question design.
Where can I find step-by-step NCERT solutions for Chapter 6 Control and Coordination Class 10 Science?
You can find complete, step-by-step NCERT solutions for Chapter 6 Control and Coordination Class 10 Science on MyAiSchool. Every intext and end-of-chapter exercise question is solved with full working, labelled diagrams and CBSE-aligned mark distribution. Solutions highlight key points about nervous system, reflex action, brain that examiners look for. This makes revision quick and exam-focused for Class 10 CBSE board students.
What is the best way to revise Control and Coordination before the Class 10 Science board exam?
The best way to revise Control and Coordination for the CBSE Class 10 Science board exam is a three-pass approach. First pass: skim the chapter and note down key terms like nervous system, reflex action, brain in a one-page mind map. Second pass: solve every NCERT intext and exercise question without looking at the solution, then self-check. Third pass: attempt previous CBSE board questions and competency-based questions under timed conditions. This structured revision secures full marks for this chapter.
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