Control and Coordination – MCQs with Answers and Explanations
Class 10
CBSE Board Examinations
Strictly per NCERT syllabus — ideal for board exam practice
Instructions: Each question has four options (A–D). Correct answer and a concise explanation follow each question. Topic-wise grouping helps targeted revision. No countdown timer included.
Nervous System — Basics (Q1–Q12)
Structure and organisation of nervous system
1. Which of the following is the basic structural and functional unit of the nervous system?
A. Neuron
B. Nerve
C. Ganglion
D. Synapse
Answer: A. Neuron. Explanation: A neuron (nerve cell) transmits electrical impulses; a nerve is a bundle of axons.
2. Dendrites in a neuron primarily function to:
A. Transmit impulses away from the cell body
B. Receive signals and transmit them toward the cell body
C. Store nutrients for the neuron
D. Produce myelin sheath
Answer: B. Receive signals. Explanation: Dendrites are branched projections that receive stimuli or signals from other neurons.
3. The central nervous system does NOT include which of the following?
A. Brain
B. Spinal cord
C. Cranial nerves
D. Cerebellum
Answer: C. Cranial nerves. Explanation: CNS includes brain and spinal cord; cranial nerves are part of the peripheral nervous system.
4. Which brain part is mainly responsible for maintaining balance and coordinating movements?
A. Cerebrum
B. Cerebellum
C. Medulla oblongata
D. Hypothalamus
Answer: B. Cerebellum. Explanation: Cerebellum integrates sensory input and fine-tunes motor activity for coordination and balance.
5. Myelin sheath around axons primarily helps to:
A. Store neurotransmitters
B. Speed up nerve impulse transmission
C. Generate nerve impulses
D. Produce cerebrospinal fluid
Answer: B. Speed up transmission. Explanation: Myelin insulates axons and enables faster (saltatory) conduction.
6. Which of the following statements about nerves is correct?
A. A nerve is a single neuron
B. A nerve is a bundle of axons/fibres
C. Nerves are only found in the brain
D. Nerves produce hormones
Answer: B. Bundle of axons. Explanation: Nerves contain many axons bound together with connective tissue and blood supply.
7. Sensory neurons are specialized to carry impulses:
A. From CNS to muscles
B. From receptors to CNS
C. Between two muscles
D. Within a single neuron
Answer: B. From receptors to CNS. Explanation: Sensory (afferent) neurons transmit information about stimuli to the central nervous system.
8. Which part of the brain is mainly responsible for voluntary actions, thinking, and memory?
A. Cerebrum
B. Cerebellum
C. Medulla
D. Spinal cord
Answer: A. Cerebrum. Explanation: Cerebrum (cerebral cortex) handles higher cognitive functions and voluntary control.
9. The role of the spinal cord includes all EXCEPT:
A. Relaying signals to/from brain
B. Processing reflexes
C. Producing insulin
D. Conducting motor commands
Answer: C. Producing insulin. Explanation: Insulin is produced by the pancreas; spinal cord relays and mediates reflexes.
10. Which of the following is an involuntary action?
A. Deciding to pick up a book
B. Breathing rate adjustment during exercise
C. Solving a math problem
D. Writing your name
Answer: B. Breathing rate adjustment. Explanation: Breathing adjustments are autonomic; they can be both involuntary and partly voluntary but primarily regulated automatically.
11. Which of the following structures is part of the peripheral nervous system?
A. Brain
B. Spinal cord
C. Cranial nerve
D. Cerebellum
Answer: C. Cranial nerve. Explanation: Cranial and spinal nerves are components of the PNS connecting CNS to body organs.
12. Which glial cells form myelin sheath in the peripheral nervous system?
A. Oligodendrocytes
B. Astrocytes
C. Schwann cells
D. Microglia
Answer: C. Schwann cells. Explanation: Schwann cells produce myelin around peripheral axons; oligodendrocytes do so in CNS.
Neuron & Nerve Impulse (Q13–Q20)
Action potential, synapse and conduction
13. Resting potential in a neuron is usually around:
A. +40 mV
B. 0 mV
C. -70 mV
D. -120 mV
Answer: C. -70 mV. Explanation: Typical resting membrane potential of many neurons is about -70 millivolts.
14. The opening of which ion channels initiates the depolarization phase of an action potential?
A. Potassium channels
B. Sodium channels
C. Chloride channels
D. Calcium channels
Answer: B. Sodium channels. Explanation: Voltage-gated Na+ channels open causing Na+ influx and depolarization.
15. Saltatory conduction occurs in:
A. Unmyelinated axons
B. Dendrites
C. Myelinated axons
D. Cell body
Answer: C. Myelinated axons. Explanation: In myelinated fibres, impulses jump between nodes of Ranvier, speeding conduction.
16. The refractory period of a neuron ensures:
A. Impulses travel both directions
B. The neuron cannot fire again immediately
C. The membrane potential remains positive
D. Continuous firing without rest
Answer: B. Cannot fire immediately. Explanation: Refractory period prevents immediate re-excitation and enforces one-way propagation.
17. Neurotransmitters are released into the synaptic cleft from:
A. Dendritic spines
B. Synaptic vesicles in presynaptic terminals
C. Nucleus
D. Myelin sheath
Answer: B. Synaptic vesicles. Explanation: Vesicles fuse with presynaptic membrane to release neurotransmitters into cleft.
18. Which ion’s entry into presynaptic terminal triggers neurotransmitter release?
A. Sodium (Na+)
B. Potassium (K+)
C. Calcium (Ca2+)
D. Chloride (Cl-)
Answer: C. Calcium. Explanation: Ca2+ influx triggers vesicle fusion and neurotransmitter exocytosis.
19. Which of the following increases the speed of impulse conduction?
A. Thinner axon diameter
B. Lack of myelination
C. Larger axon diameter and myelination
D. Fewer nodes of Ranvier
Answer: C. Larger diameter and myelination. Explanation: Both factors reduce resistance and enhance conduction velocity.
20. An inhibitory postsynaptic potential (IPSP) typically results from:
A. Influx of Na+
B. Efflux of K+ or influx of Cl-
C. Release of acetylcholinesterase
D. Opening of gap junctions
Answer: B. Efflux of K+ or influx of Cl-. Explanation: These changes hyperpolarize the membrane, reducing chance of firing.
Reflex Actions (Q21–Q26)
Reflex arc components and examples
21. A reflex action is best described as:
A. A slow, learned response
B. An involuntary, rapid response
C. A hormonal response
D. A voluntary movement
Answer: B. Involuntary, rapid response. Explanation: Reflexes protect the body and are processed in the spinal cord for speed.
22. Which of the following correctly lists components of a reflex arc in order?
A. Receptor → motor neuron → sensory neuron → effector
B. Receptor → sensory neuron → spinal cord → motor neuron → effector
C. Effector → receptor → spinal cord → motor neuron
D. Sensory neuron → receptor → brain → motor neuron
Answer: B. Receptor → sensory → spinal cord → motor → effector. Explanation: This sequence allows rapid, protective responses.
23. The knee-jerk (patellar) reflex is an example of a:
A. Polysynaptic reflex
B. Monosynaptic reflex
C. Learned response
D. Voluntary action
Answer: B. Monosynaptic reflex. Explanation: Sensory neuron directly synapses with motor neuron, giving a very fast response.
24. Withdrawal of hand from a hot object is primarily mediated by:
A. Cerebral cortex processing
B. Spinal cord reflex arc
C. Endocrine response
D. Slow hormonal signalling
Answer: B. Spinal cord reflex arc. Explanation: Local spinal circuits trigger rapid withdrawal before the brain processes the sensation.
25. Which statement about reflex actions is FALSE?
A. They are automatic
B. They are slower than voluntary actions
C. They may involve interneurons
D. They help protect the body
Answer: B. They are slower than voluntary actions (False). Explanation: Reflexes are faster than voluntary responses.
26. An exaggerated tendon reflex might indicate damage to:
A. Peripheral nerves
B. Upper motor neurons (brain pathways)
C. Muscle fibres only
D. Sensory receptors
Answer: B. Upper motor neurons. Explanation: Loss of inhibitory control from the brain leads to hyperreflexia, seen in upper motor neuron lesions.
Endocrine System & Hormones (Q27–Q38)
Glands, hormones and physiological roles
27. Which gland is often called the 'master gland' and why?
A. Thyroid — controls metabolism
B. Pituitary — regulates other endocrine glands
C. Adrenal — secretes adrenaline
D. Pancreas — controls blood sugar
Answer: B. Pituitary. Explanation: Pituitary secretes hormones that control several other endocrine glands (TSH, ACTH, FSH, LH, GH).
28. Insulin acts to:
A. Raise blood glucose
B. Lower blood glucose by promoting uptake
C. Stimulate production of adrenaline
D. Cause breakdown of proteins
Answer: B. Lower blood glucose. Explanation: Insulin promotes glucose uptake in tissues and glycogen synthesis in liver.
29. Which hormone is responsible for the 'fight or flight' response?
A. Insulin
B. Adrenaline (epinephrine)
C. Thyroxine
D. Growth hormone
Answer: B. Adrenaline. Explanation: Adrenaline increases heart rate, breathing and energy availability during acute stress.
30. Glucagon functions to:
A. Lower blood sugar
B. Increase blood sugar by stimulating glycogen breakdown
C. Inhibit protein synthesis
D. Promote water retention
Answer: B. Increase blood sugar. Explanation: Glucagon stimulates glycogenolysis and gluconeogenesis in the liver.
31. Which hormone regulates basal metabolic rate and growth?
A. Insulin
B. Thyroxine
C. Adrenaline
D. Glucagon
Answer: B. Thyroxine. Explanation: Thyroid hormones control metabolism and are essential for growth and development.
32. A deficiency of insulin leads to:
A. Hypoglycaemia
B. Diabetes mellitus (hyperglycaemia)
C. Low blood pressure
D. Increased muscle mass
Answer: B. Diabetes mellitus. Explanation: Lack of insulin or insulin action causes elevated blood glucose and diabetes symptoms.
33. Which hormone promotes seed germination and stem elongation in plants?
A. Abscisic acid (ABA)
B. Auxin
C. Gibberellin
D. Ethylene
Answer: C. Gibberellin. Explanation: Gibberellins break dormancy and promote growth processes like stem elongation.
34. Which endocrine gland sits below the hypothalamus and controls other glands?
A. Thyroid
B. Pituitary
C. Pancreas
D. Adrenal
Answer: B. Pituitary. Explanation: Pituitary (controlled by hypothalamus) secretes multiple trophic hormones.
35. Which hormone causes stomatal closure during water stress in plants?
A. Auxin
B. Gibberellin
C. Abscisic acid (ABA)
D. Ethylene
Answer: C. Abscisic acid. Explanation: ABA signals guard cells to lose turgor, closing stomata to conserve water.
36. Which hormone is primarily responsible for development of secondary sexual characteristics in males?
A. Oestrogen
B. Progesterone
C. Testosterone
D. Prolactin
Answer: C. Testosterone. Explanation: Testosterone produced by testes controls male secondary sexual traits and spermatogenesis.
Control & Coordination in Plants (Q39–Q44)
Plant hormones, tropisms and movements
37. Phototropism is best described as:
A. Growth response to gravity
B. Movement independent of stimulus direction
C. Growth response toward or away from light
D. Rapid folding of leaves on touch
Answer: C. Growth toward/away from light. Explanation: Phototropism helps shoots orient to capture light; auxin redistribution drives differential growth.
38. Which plant movement is non-directional and often rapid (e.g., Mimosa leaf closing)?
A. Phototropism
B. Geotropism
C. Nastic movement
D. Chemotropism
Answer: C. Nastic movement. Explanation: Nastic movements are independent of stimulus direction and often caused by turgor changes.
39. Auxin mainly promotes:
A. Cell elongation
B. Seed dormancy
C. Fruit ripening
D. Leaf abscission
Answer: A. Cell elongation. Explanation: Auxin stimulates elongation, particularly in shoots, aiding tropic responses.
40. Ethylene in plants primarily affects:
A. Photosynthesis rate
B. Fruit ripening and senescence
C. Root water uptake
D. Nitrogen fixation
Answer: B. Fruit ripening. Explanation: Ethylene triggers ripening processes and abscission in plants.
41. Geotropism causes roots to grow:
A. Away from gravity (negative)
B. Toward gravity (positive)
C. Toward light
D. Randomly
Answer: B. Toward gravity. Explanation: Roots show positive geotropism, growing downward in response to gravity.
Comparisons & Miscellaneous (Q42–Q50)
Useful quick facts and exam-oriented comparisons
42. Which of the following is TRUE about hormones and neurotransmitters?
A. Both act at the same speed
B. Hormones act slower but have longer effects; neurotransmitters act faster
C. Neurotransmitters are released into blood
D. Hormones are used only for digestion
Answer: B. Hormones slower, longer; neurotransmitters faster. Explanation: Nervous system is rapid and specific; endocrine is slower and systemic.
43. Homeostasis refers to:
A. Change of environment
B. Maintaining stable internal conditions
C. Rapid muscle contraction
D. Seed germination
Answer: B. Maintaining stable internal conditions. Explanation: Both nervous and endocrine systems play key roles in homeostasis.
44. Which is NOT an effect of adrenaline?
A. Increased heart rate
B. Dilated airways
C. Increased digestion
D. Increased blood flow to muscles
Answer: C. Increased digestion (False). Explanation: Adrenaline suppresses digestion during 'fight-or-flight'.
45. Which of the following best describes a synapse?
A. A cell organelle
B. Junction between two neurons
C. Type of hormone
D. A blood vessel
Answer: B. Junction between two neurons. Explanation: Synapse allows communication via neurotransmitters or electrical coupling.
46. Which of the following statements about plant hormones is correct?
A. They act only at high concentrations
B. They regulate growth and responses at low concentrations
C. They are identical to animal hormones
D. They are ineffective in tropisms
Answer: B. Act at low concentrations. Explanation: Plant hormones are potent and effective at very low levels to regulate development.
47. Which organ performs both endocrine and exocrine functions?
A. Thyroid
B. Pancreas
C. Adrenal
D. Pituitary
Answer: B. Pancreas. Explanation: Pancreas secretes digestive enzymes (exocrine) and hormones like insulin (endocrine).
48. Which of the following is an example of a tropism?
A. Closing of Mimosa leaves
B. Phototropism of a shoot bending toward light
C. Opening of flowers at dawn
D. Random seed dispersal
Answer: B. Phototropism. Explanation: Tropisms are directional growth responses towards/away from stimuli.
49. Which process shows interaction between nervous and endocrine systems?
A. Reflex arc
B. Hypothalamus regulating pituitary secretion
C. Phototropism
D. Saltatory conduction
Answer: B. Hypothalamus regulates pituitary. Explanation: Hypothalamus (neural) controls pituitary (endocrine), integrating both systems.
50. For CBSE board exam preparation, best advice is to:
A. Memorize definitions only
B. Understand concepts, practice diagrams and MCQs
C. Ignore NCERT textbook
D. Study random internet notes only
Answer: B. Understand concepts and practice. Explanation: NCERT-based understanding, diagrams and practice questions give best board preparation outcome.