Neural Control and Coordination: impulse, brain, eye and ear

Free questions

30 solved MCQs, answer marked and reasoning written out

Every question below is free to read — no sign-up, no email. 2 of them are real questions from past NEET papers. The other 142 questions in this chapter are in the book and in practice access.

1. Q1 Multi-statement analysis

   Regarding CNS and PNS: (i) the human neural system has two parts, the CNS and the PNS (ii) the CNS includes the brain and the spinal cord and is the site of information processing and control (iii) the PNS comprises all the nerves of the body associated with the CNS (iv) the PNS, not the CNS, is the site of information processing and control. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; information processing and control is the role of the CNS, so (iv) is wrong.

   What this is testing: which half of the neural system does the processing.

   (i) is correct. The human neural system has two parts, central and peripheral.
   (ii) is correct. The CNS is the brain and spinal cord, and it is where information is processed and control is exercised.
   (iii) is correct. The PNS is all the nerves of the body linked to the CNS.
   (iv) is the trap. It gives the processing role to the PNS.

   So three are correct. Statements (ii) and (iv) flatly contradict each other. The PNS is wiring; the CNS is the decision-maker. Central means the centre where decisions are made.

   CNS processes, PNS carries. Brain and cord on one side, all the nerves on the other.

   NCERT Class 11 Biology, page 231

2. Q2 Multi-statement analysis

   Regarding synapses in general: (i) a nerve impulse passes from one neuron to another through junctions called synapses (ii) a synapse is formed by the membranes of a pre-synaptic and a post-synaptic neuron (iii) these two membranes may or may not be separated by a synaptic cleft (iv) synapses may be either electrical or chemical in type. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four are correct.

   What this is testing: the basic definition of a synapse.

   All four are correct.
   (i) A nerve impulse passes from one neuron to the next at a junction called a synapse.
   (ii) A synapse is formed by the membranes of a pre-synaptic and a post-synaptic neuron.
   (iii) Those membranes may or may not be separated by a synaptic cleft.
   (iv) Synapses come in two types, electrical and chemical.

   So all four are correct. Statement (iii) is the one students reject, because they remember the cleft from the chemical synapse diagram. The 'may or may not' is exactly right: chemical synapses have a cleft, electrical ones do not.

   Pre-synaptic membrane, post-synaptic membrane, and a cleft that may or may not be there. Its presence decides which type of synapse it is.

   NCERT Class 11 Biology, page 234

3. Q3 Multi-statement analysis

   Regarding unmyelinated nerve fibres: (i) they are enclosed by a Schwann cell that does not form a myelin sheath (ii) they are commonly found in the autonomic and somatic neural systems (iii) myelinated fibres, by contrast, are found in the spinal and cranial nerves (iv) unlike myelinated fibres, unmyelinated fibres lack nodes of Ranvier. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four are correct.

   What this is testing: the features of an unmyelinated nerve fibre.

   All four are correct.
   (i) An unmyelinated fibre is enclosed by a Schwann cell, but that cell does not form a myelin sheath around it.
   (ii) Such fibres are common in the autonomic and somatic neural systems.
   (iii) Myelinated fibres are the ones found in spinal and cranial nerves.
   (iv) Unmyelinated fibres have no nodes of Ranvier.

   So all four are correct. Statement (i) is the one students doubt, because they read 'Schwann cell' and assume myelin must follow. A Schwann cell is present in both kinds of fibre; only in the myelinated kind does it wrap into a sheath.

   Schwann cells wrap both kinds; only some lay down myelin. Myelinated fibres are found in the spinal and cranial nerves.

   NCERT Class 11 Biology, page 232

4. Q4 Multi-statement analysis

   Regarding neuron types by axon/dendrite number: (i) multipolar neurons have one axon and two or more dendrites and are found in the cerebral cortex (ii) bipolar neurons have one axon and one dendrite and are found in the retina of the eye (iii) unipolar neurons have one axon and two or more dendrites (iv) multipolar neurons are usually found in the embryonic stage. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i)–(ii) correct; (iii) actually describes the MULTIPOLAR neuron, and (iv) wrongly assigns the embryonic-stage unipolar neuron's description to multipolar neurons.

   What this is testing: the three neuron types named by how many processes they carry.

   (i) is correct. Multipolar neurons have one axon and two or more dendrites, and they are found in the cerebral cortex.
   (ii) is correct. Bipolar neurons have one axon and one dendrite, and they are found in the retina.
   (iii) is wrong. One axon with two or more dendrites is the MULTIPOLAR neuron. A unipolar neuron has only a cell body and one axon, and is found in the embryonic stage.
   (iv) is wrong for the same reason: the embryonic stage belongs to the unipolar neuron.

   So two are correct. Count the poles from the name: uni one, bi two, multi many.

   Multipolar in the cortex, bipolar in the retina, unipolar in the embryo. Counting processes names the neuron.

   NCERT Class 11 Biology, page 232

5. Q5 Multi-statement analysis

   Regarding propagation and repolarisation: (i) the sequence of depolarisation is repeated along the axon so that the impulse is conducted (ii) the rise in stimulus-induced Na+ permeability is extremely short-lived (iii) it is quickly followed by a rise in K+ permeability (iv) K+ diffusing outside the membrane further increases the depolarisation of the site. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; the outward diffusion of K+ RESTORES the resting potential (repolarises), it does not deepen depolarisation.

   What this is testing: what the outward movement of K+ does to the membrane.

   (i) is correct. The depolarisation sequence repeats along the axon, and that is how the impulse travels.
   (ii) is correct. The stimulus-driven rise in Na+ permeability lasts only a moment.
   (iii) is correct. A rise in K+ permeability follows quickly.
   (iv) is the trap. K+ leaving the cell RESTORES the resting potential — it repolarises the membrane. It does not deepen the depolarisation.

   So three are correct. Keep the two ions apart by what they do: Na+ moving in causes the firing, K+ moving out ends it and resets the membrane for the next impulse.

   Sodium in, then potassium out. The second wave restores the resting state, which is why a nerve can fire again within milliseconds.

   NCERT Class 11 Biology, page 233

6. Q6 Multi-statement analysis

   Regarding the resting axoplasm and its surroundings: (i) the membrane is impermeable to negatively charged proteins in the axoplasm (ii) the axoplasm contains a high concentration of K+ and negatively charged proteins (iii) the fluid outside the axon contains a low concentration of Na+ (iv) the fluid outside the axon contains a high concentration of K+. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i)–(ii) correct; (iii) reverses the outside fluid's Na+ level — it is HIGH, not low — and (iv) is also wrong, since the outside fluid has a LOW concentration of K+.

   What this is testing: the ion concentrations inside and outside the resting axon.

   (i) is correct. The membrane will not let the negatively charged proteins of the axoplasm out.
   (ii) is correct. The axoplasm is rich in K+ and in those negatively charged proteins.
   (iii) is wrong. The fluid outside has a HIGH concentration of Na+, not a low one.
   (iv) is wrong too. The outside fluid is LOW in K+, not high.

   So two are correct. Fix the picture once and both errors collapse: potassium is the inside ion, sodium is the outside ion. Statements (iii) and (iv) each take one of those and flip it.

   Potassium and proteins inside, sodium outside. That asymmetry is the battery the whole nervous system runs on.

   NCERT Class 11 Biology, page 232

7. Q7 Multi-statement analysis

   Regarding the sodium-potassium pump: (i) ionic gradients across the resting membrane are maintained by the active transport of ions (ii) the pump transports 3 Na+ outwards for every 2 K+ moved into the cell (iii) as a result, the outer surface of the axonal membrane possesses a positive charge (iv) the pump transports 2 Na+ outwards for every 3 K+ moved into the cell. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; the pump ratio is 3 Na+ OUT for 2 K+ IN, not the reverse given in (iv).

   What this is testing: the exchange ratio of the sodium-potassium pump.

   (i) is correct. Active transport keeps the ionic gradients across the resting membrane.
   (ii) is correct. The pump pushes 3 Na+ out for every 2 K+ it brings in.
   (iii) is correct. That is why the outer surface of the axonal membrane ends up positive.
   (iv) is the trap, with the numbers swapped.

   So three are correct. The ratio matters because it is uneven: more positive charge leaves than enters, which is what makes the outside positive. Learn it as 3 out, 2 in, and remember that sodium is the one being thrown out.

   Three sodium out for two potassium in - an unequal trade, which is precisely what leaves the outside positive.

   NCERT Class 11 Biology, page 233

8. Q8 Multi-statement analysis

   Regarding the action potential: (i) it is the electrical potential difference across the membrane at a depolarised site (ii) it is identical to the resting potential (iii) at sites immediately ahead, the membrane still has a positive outer surface and a negative inner surface (iv) current flows on the inner surface of the axon from site B back to site A to complete the circuit. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i) and (iii) correct; (ii) is wrong because the action potential is distinct from the resting potential, and (iv) is also wrong, since on the inner surface current actually flows from site A to site B.

   What this is testing: what the action potential is and how current flows during propagation.

   (i) is correct. The action potential is the potential difference across the membrane at a depolarised site.
   (iii) is correct. Just ahead of that site the membrane still has a positive outside and a negative inside.
   (ii) is wrong. The action potential is not the same as the resting potential — they are opposite states of the membrane.
   (iv) is wrong. On the INNER surface, current flows from site A to site B, not from B back to A. The outer surface is where it runs from B to A.

   So two are correct. Fix the loop once: inside forward, outside backward.

   Action potential is the reversal; resting potential is the polarised state it replaces. Calling them identical erases the whole mechanism.

   NCERT Class 11 Biology, page 233

9. Q9 Assertion and Reason

   AssertionThe sodium-potassium pump transports 3 Na+ outward for every 2 K+ inward.

   ReasonThe fluid outside the axon contains a high concentration of Na+ and a low concentration of K+.

   1. 1.Both A and R are true and R is the correct explanation of A
   2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
   3. 3.A is true but R is false
   4. 4.A is false but R is true

   Why option 2 is the answer

   The trap: Both are true resting-state facts running in parallel; the extracellular composition does not itself explain the pump's fixed transport ratio.

   What this is testing: whether the outside ion levels explain the pump's ratio.

   A says the sodium-potassium pump moves 3 Na+ out for every 2 K+ in. True.
   R says the fluid outside the axon is high in Na+ and low in K+. True.

   Both true, but R does not explain A, so the code is (2).

   The trap: the two lines are about the same ions in the same resting membrane, and that closeness reads as cause and effect. It is the other way round if anything — the pump helps create those outside concentrations. A description of the result cannot explain the fixed 3:2 ratio.

   NCERT Class 11 Biology, page 233

10. Q10 Assertion and Reason

    AssertionThe corpora quadrigemina form the dorsal portion of the midbrain.

    ReasonThe midbrain receives and integrates visual, tactile and auditory inputs.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of the midbrain running in parallel; the corpora quadrigemina's location does not itself explain the integrative function.

    What this is testing: two separate facts about the midbrain.

    A says the corpora quadrigemina form the dorsal part of the midbrain. True — dorsal means the upper or back side.
    R says the midbrain receives and integrates visual, tactile and auditory inputs. True.

    Both true, but R does not explain A, so the code is (2).

    The trap: a position and a function in the same structure feel like one story. Where the four lobes sit does not explain why the midbrain integrates those inputs. R must answer 'why is A so?', not simply add another true midbrain fact.

    NCERT Class 11 Biology, page 236

11. Q11 Assertion and Reason

    AssertionThe medulla contains centres controlling respiration, cardiovascular reflexes and gastric secretions.

    ReasonThe medulla is directly connected to the spinal cord.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of the medulla running in parallel; its connection to the spinal cord does not explain its specific control centres.

    What this is testing: what the medulla controls and where it sits.

    A says the medulla contains centres for respiration, cardiovascular reflexes and gastric secretions. True.
    R says the medulla is directly connected to the spinal cord. True.

    Both true, but R does not explain A, so the code is (2).

    The trap: a fact about position feels like it should account for the function, since both are about the same small structure. Being joined to the spinal cord does not explain why breathing and heart reflexes are controlled there. R must answer 'why?', not merely add.

    NCERT Class 11 Biology, page 236

12. Q12 Assertion and Reason

    AssertionEfferent nerve fibres carry impulses from tissues and organs to the CNS.

    ReasonAfferent nerve fibres transmit impulses from tissues/organs to the CNS.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — it is the afferent fibres that carry impulses towards the CNS, while efferent fibres carry impulses away from it; R is true.

    What this is testing: the direction of efferent and afferent fibres.

    A says efferent fibres carry impulses from tissues and organs to the CNS. False. Efferent fibres carry impulses AWAY from the CNS, out to the organs.
    R says afferent fibres carry impulses from tissues and organs to the CNS. True — and it is what makes A false.

    A false and R true is code (4).

    The trap: A and R claim the same job for two different fibre types, so they cannot both stand. A for arriving at the centre, E for exiting from it.

    NCERT Class 11 Biology, page 231

13. Q13 Assertion and Reason

    AssertionThe CNS is the site of information processing and control in the body.

    ReasonThe CNS is composed of the brain and the spinal cord.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of the CNS; its anatomical composition is a parallel fact and does not by itself explain its processing role.

    What this is testing: the role of the CNS against its make-up.

    A says the CNS is the site of information processing and control. True.
    R says the CNS is made of the brain and the spinal cord. True.

    Both true, but R does not explain A, so the code is (2).

    The trap: naming the organs feels like explaining the function, because the brain is famous for thinking. But R only lists what the CNS is built from; it does not say why processing happens there. A list of parts is an inventory, not a reason.

    NCERT Class 11 Biology, page 231

14. Q14 Assertion and Reason

    AssertionThe somatic neural system relays impulses from the CNS to skeletal muscles.

    ReasonThe autonomic neural system transmits impulses from the CNS to involuntary organs and smooth muscles.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of the two PNS divisions running in parallel; one does not explain the other.

    What this is testing: what the somatic and autonomic systems each supply.

    A says the somatic neural system relays impulses from the CNS to skeletal muscles. True.
    R says the autonomic neural system carries impulses from the CNS to involuntary organs and smooth muscles. True.

    Both true, but R does not explain A, so the code is (2).

    The trap: the two lines are a matched pair, and a neat pair reads as cause and effect. What the autonomic system does cannot explain what the somatic system does. They are two parallel divisions of the same peripheral system.

    NCERT Class 11 Biology, page 231

15. Q15 Assertion and Reason

    AssertionElectrical synapses are common in the human nervous system and are slower than chemical synapses.

    ReasonImpulse transmission across an electrical synapse is always faster than across a chemical synapse.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false on both counts — electrical synapses are rare and are faster, not slower; R is true.

    What this is testing: how common and how fast electrical synapses are.

    A says electrical synapses are common in the human nervous system and slower than chemical ones. False on both counts. They are RARE, and they are FASTER.
    R says transmission across an electrical synapse is always faster than across a chemical one. True, and it contradicts the second half of A.

    A false and R true is code (4).

    The trap: A packs two claims into one line, so a student who checks only 'common' may stop there. Read to the end; one wrong word is enough to sink the whole assertion.

    NCERT Class 11 Biology, page 234

16. Q16 Assertion and Reason

    AssertionThe dura mater is the innermost cranial meningeal layer, in contact with the brain tissue.

    ReasonThe pia mater is the inner layer of the cranial meninges that is in contact with the brain tissue.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — the dura mater is the OUTER layer; R is true.

    What this is testing: which meningeal layer touches the brain.

    A says the dura mater is the innermost layer, in contact with the brain tissue. False. The dura mater is the OUTER layer.
    R says the pia mater is the inner layer in contact with the brain tissue. True, and it is what makes A false.

    A false and R true is code (4).

    The trap: A and R claim the same position for two different layers, so one must be wrong. Order them from outside in — dura, arachnoid, pia — and remember that the tough dura guards the outside while the delicate pia hugs the brain.

    NCERT Class 11 Biology, page 235

17. Q17 Assertion and Reason

    AssertionThe midbrain lies between the thalamus/hypothalamus of the forebrain and the pons of the hindbrain.

    ReasonA canal called the cerebral aqueduct passes through the midbrain.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of the midbrain; the presence of the aqueduct is a parallel structural fact and does not explain the midbrain's position.

    What this is testing: two separate facts about the midbrain.

    A says the midbrain lies between the thalamus and hypothalamus of the forebrain and the pons of the hindbrain. True — it sits in the middle, as its name says.
    R says a canal called the cerebral aqueduct passes through the midbrain. True.

    Both true, but R does not explain A, so the code is (2).

    The trap: two true midbrain facts sitting together look linked. A canal running through a structure says nothing about where that structure lies. Position and contents are separate questions.

    NCERT Class 11 Biology, page 236

18. Q18 Statement I and Statement II

    Statement IThe hindbrain consists of the cerebrum, thalamus and hypothalamus.

    Statement IIThe forebrain consists of the pons, cerebellum and medulla.

    1. 1.Both Statement I and Statement II are correct
    2. 2.Both Statement I and Statement II are incorrectCorrect answer
    3. 3.Statement I is correct but Statement II is incorrect
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 2 is the answer

    The trap: Both incorrect — the components are swapped: cerebrum/thalamus/hypothalamus form the forebrain, and pons/cerebellum/medulla form the hindbrain.

    What this is testing: which structures belong to the forebrain and which to the hindbrain.

    Statement I says the hindbrain is the cerebrum, thalamus and hypothalamus. Incorrect — that is the forebrain.
    Statement II says the forebrain is the pons, cerebellum and medulla. Incorrect — that is the hindbrain.

    Both incorrect, so the answer is (2).

    The trap: the two lists are simply swapped between the two labels, and each list on its own is a real one from the book. Learn the lists tied to their divisions, not floating free, and both lines fall in one go.

    NCERT Class 11 Biology, page 236

19. Q19 Statement I and Statement II

    Statement IThe corpora quadrigemina are four round swellings on the dorsal midbrain.

    Statement IIThe cerebral aqueduct passes through the medulla.

    1. 1.Both Statement I and Statement II are correct
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrectCorrect answer
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 3 is the answer

    The trap: I is correct; the cerebral aqueduct passes through the MIDBRAIN, not the medulla, so II is incorrect.

    What this is testing: two structures of the midbrain.

    Statement I says the corpora quadrigemina are four round swellings on the dorsal midbrain. Correct — quadri means four.
    Statement II says the cerebral aqueduct passes through the medulla. Incorrect — the cerebral aqueduct runs through the MIDBRAIN.

    So I correct, II incorrect, giving (3).

    The trap: the medulla is a nearby brain-stem structure, so the swap reads smoothly. Both of these features belong to the midbrain — corpora quadrigemina on its back, cerebral aqueduct running through it. Keep the pair together.

    NCERT Class 11 Biology, page 236

20. Q20 Statement I and Statement II

    Statement IThe limbic system includes the amygdala and the hippocampus.

    Statement IIAlong with the hypothalamus, the limbic system regulates emotional reactions such as rage and fear.

    1. 1.Both Statement I and Statement II are correctCorrect answer
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrect
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 1 is the answer

    The trap: Both statements are correct.

    What this is testing: the parts of the limbic system and what it does.

    Statement I says the limbic system includes the amygdala and the hippocampus. Correct.
    Statement II says that, with the hypothalamus, it regulates emotional reactions such as rage and fear. Correct.

    Both correct, so the answer is (1).

    One line gives the parts, the other the function, and both are straight from the book. The difficulty is only confidence: amygdala and hippocampus are unusual words, and unfamiliar words tempt students to mark a statement wrong just because they are unsure of it.

    NCERT Class 11 Biology, page 236

21. Q21 Match the columns

    Match the brain division with its components:

    Column I	Column II
    (a) Forebrain	(i) midbrain, pons, medulla oblongata
    (b) Midbrain	(ii) pons, cerebellum, medulla
    (c) Hindbrain	(iii) cerebrum, thalamus, hypothalamus
    (d) Brain stem	(iv) corpora quadrigemina, cerebral aqueduct

    1. 1.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
    2. 2.(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)
    3. 3.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)Correct answer
    4. 4.(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

    Why option 3 is the answer

    The trap: Forebrain-cerebrum/thalamus/hypothalamus, midbrain-corpora quadrigemina/aqueduct, hindbrain-pons/cerebellum/medulla, brain stem-midbrain+pons+medulla.

    What this is testing: the components of each brain division.

    The forebrain is the cerebrum, thalamus and hypothalamus. The midbrain carries the corpora quadrigemina and the cerebral aqueduct. The hindbrain is the pons, cerebellum and medulla. The brain stem is the midbrain, pons and medulla oblongata together.

    That gives (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i) — option 3.

    The trap: (d) overlaps with (b) and (c), since the brain stem borrows parts from both. Do not let that overlap unsettle you. Match the three divisions first; the brain stem is then the only entry left.

    NCERT Class 11 Biology, page 236

22. Q22 Match the columns

    Match the forebrain component with its function:

    Column I	Column II
    (a) Cerebral cortex	(ii) coordinating centre for sensory and motor signalling
    (b) Thalamus	(i) centres for body temperature, hunger and thirst
    (c) Hypothalamus	(iv) sexual behaviour, emotional reactions, motivation
    (d) Limbic system	(iii) motor, sensory and association areas

    1. 1.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
    2. 2.(a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
    3. 3.(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)
    4. 4.(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)Correct answer

    Why option 4 is the answer

    The trap: Cortex-motor/sensory/association areas, thalamus-coordinating centre, hypothalamus-temperature/hunger/thirst, limbic system-emotion/motivation.

    What this is testing: the parts of the forebrain and the job of each.

    The cerebral cortex holds the motor, sensory and association areas. The thalamus coordinates sensory and motor signalling. The hypothalamus controls body temperature, hunger and thirst. The limbic system handles sexual behaviour, emotional reactions and motivation.

    That gives (a)-(iii), (b)-(ii), (c)-(i), (d)-(iv) — option 4.

    The trap: option 2 gives the hypothalamus's temperature and hunger centres to the cortex and hands the cortex's areas to the hypothalamus. Fix the hypothalamus by its famous jobs — temperature, hunger, thirst — and that option falls straight away.

    NCERT Class 11 Biology, page 236

23. Q23 Match the columns

    Match the membrane event with the potential it represents:

    Column I	Column II
    (a) Membrane at rest	(i) excitatory or inhibitory potential
    (b) Membrane at a stimulated, depolarised site	(ii) repolarisation
    (c) Restoration after K+ efflux	(iii) action potential
    (d) New potential in the post-synaptic neuron	(iv) resting potential

    1. 1.(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
    2. 2.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
    3. 3.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)Correct answer
    4. 4.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)

    Why option 3 is the answer

    The trap: Resting membrane-resting potential, depolarised site-action potential, restoration-repolarisation, post-synaptic-excitatory/inhibitory.

    What this is testing: the name given to each electrical state of the membrane.

    The membrane at rest shows the resting potential. A stimulated, depolarised site shows the action potential. Restoration after K+ leaves is repolarisation. The new potential raised in the post-synaptic neuron is either excitatory or inhibitory.

    That gives (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) — option 3.

    The trap: option 1 swaps resting and action potential, treating the depolarised site as the resting one. They are opposite conditions of the same membrane — resting means polarised and quiet, action means depolarised and firing.

    NCERT Class 11 Biology, page 233

24. Q24 Match the columns

    Match the brain structure with the function noted in the chapter summary:

    Column I	Column II
    (a) Midbrain	(i) integrates information from the semicircular canals of the ear and the auditory system
    (b) Cerebellum	(ii) concerned with olfaction, autonomic responses, sexual behaviour and motivation
    (c) Hypothalamus	(iii) integrates visual, tactile and auditory inputs
    (d) Limbic system	(iv) controls body temperature, eating and drinking

    1. 1.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
    2. 2.(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)Correct answer
    3. 3.(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
    4. 4.(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

    Why option 2 is the answer

    The trap: Midbrain-visual/tactile/auditory integration, cerebellum-ear/auditory integration, hypothalamus-temperature/eating/drinking, limbic system-olfaction/emotion/motivation.

    What this is testing: the function the chapter summary gives to each structure.

    The midbrain integrates visual, tactile and auditory inputs. The cerebellum integrates information from the semicircular canals of the ear and the auditory system. The hypothalamus controls body temperature, eating and drinking. The limbic system deals with olfaction, autonomic responses, sexual behaviour and motivation.

    That gives (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) — option 2.

    The trap: option 1 swaps the midbrain and cerebellum, and both entries mention hearing. The ear's balance organ, the semicircular canals, is the word that marks the cerebellum.

    NCERT Class 11 Biology, page 237

25. Q25 Exception / incorrect

    All of the following are true of afferent and efferent fibres EXCEPT:

    1. 1.Afferent fibres transmit impulses from tissues/organs to the CNS
    2. 2.Afferent fibres transmit impulses from the CNS to peripheral tissues/organsCorrect answer
    3. 3.Efferent fibres transmit regulatory impulses from the CNS to peripheral tissues/organs
    4. 4.Both are types of PNS nerve fibres

    Why option 2 is the answer

    The trap: It is the EFFERENT fibres that carry impulses from the CNS to peripheral tissues/organs.

    What this is testing: the direction each fibre type carries impulses.

    The exception is option 2. Afferent fibres carry impulses from tissues and organs TO the CNS. Carrying impulses from the CNS out to the tissues is the job of the efferent fibres, which option 3 states correctly.

    Why the others stand: option 1 gives the afferent direction correctly, option 3 the efferent direction, and option 4 rightly calls both PNS fibre types.

    The trap: options 1 and 2 give opposite directions to the same fibre, so one must be wrong. A for arriving at the CNS, E for exiting from it.

    NCERT Class 11 Biology, page 231

26. Q26 Exception / incorrect

    All of the following are true of neuron types EXCEPT:

    1. 1.Unipolar neurons have one axon and two or more dendritesCorrect answer
    2. 2.Multipolar neurons have one axon and two or more dendrites
    3. 3.Bipolar neurons are found in the retina of the eye
    4. 4.Unipolar neurons are usually found in the embryonic stage

    Why option 1 is the answer

    The trap: That description — one axon and two or more dendrites — fits the MULTIPOLAR neuron, not the unipolar one.

    What this is testing: which neuron type has many dendrites.

    The exception is option 1. One axon with two or more dendrites describes the MULTIPOLAR neuron, as option 2 says. A unipolar neuron has a cell body with only one axon.

    Why the others stand: multipolar neurons do have one axon and several dendrites, bipolar neurons are found in the retina, and unipolar neurons are usually seen in the embryonic stage.

    The trap: options 1 and 2 give the same description to two different neurons, so one is wrong. Count the poles from the name — uni one, bi two, multi many.

    NCERT Class 11 Biology, page 232

27. Q27 Sequence / ordering

    Arrange the following in the correct order of branching of the human neural system, from the whole system down to its smallest named division:

    1. 1.Peripheral neural system → human neural system → sympathetic neural system → autonomic neural system
    2. 2.Human neural system → autonomic neural system → peripheral neural system → sympathetic neural system
    3. 3.Human neural system → peripheral neural system → autonomic neural system → sympathetic neural systemCorrect answer
    4. 4.Autonomic neural system → sympathetic neural system → human neural system → peripheral neural system

    Why option 3 is the answer

    The trap: The human neural system divides into CNS/PNS; the PNS divides into somatic/autonomic; the autonomic divides into sympathetic/parasympathetic.

    What this is testing: how the neural system branches from the whole down to the smallest named part.

    The human neural system splits into CNS and PNS. The PNS splits into somatic and autonomic. The autonomic splits into sympathetic and parasympathetic.

    That order is option 3.

    The trap: option 2 puts the autonomic system above the peripheral one, which inverts two levels of the ladder. Ask at each step which is the container and which is the part. The autonomic system sits inside the PNS, so it can never come before it.

    NCERT Class 11 Biology, page 231

28. Q28 Sequence / ordering

    Arrange the parts of a neuron in the correct order along the path taken by a nerve impulse as it is generated and passed on:

    1. 1.Axon → cell body → dendrite → synaptic knob
    2. 2.Synaptic knob → axon → cell body → dendrite
    3. 3.Dendrite → cell body → axon → synaptic knobCorrect answer
    4. 4.Cell body → synaptic knob → dendrite → axon

    Why option 3 is the answer

    The trap: Impulses travel from the dendrite towards the cell body, then away along the axon to the synaptic knob.

    What this is testing: the path of an impulse through the parts of one neuron.

    The impulse comes in along a dendrite, passes to the cell body, travels out along the axon, and reaches the synaptic knob at the axon's end.

    That order is option 3.

    The trap: option 1 starts with the axon and ends with the dendrite, which reverses the whole route. Fix the traffic rule once — dendrites bring impulses in, the axon takes them out — and the knob has to be last, because it is the point where the signal is handed to the next cell.

    NCERT Class 11 Biology, page 232

29. Q29 NEET 2022

    Match List-I with List-II:

    Column I	Column II
    (a) Multipolar neuron	(i) Somatic neural system
    (b) Bipolar neuron	(iii) Spinal nerves
    (c) Myelinated nerve fibre	(ii) Retina of the eye
    (d) Unmyelinated nerve fibre	(iv) Cerebral cortex

    1. 1.(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
    2. 2.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
    3. 3.(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
    4. 4.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)Correct answer

    Why option 4 is the answer

    The trap: Multipolar neurons dominate the cerebral cortex, bipolar neurons occur in the retina, myelinated fibres run in the spinal nerves, and unmyelinated fibres are typical of the somatic neural system.

    What this is testing: where two neuron types and two fibre types are found.

    Multipolar neurons are found in the cerebral cortex. Bipolar neurons are found in the retina. Myelinated fibres run in the spinal nerves. Unmyelinated fibres are typical of the somatic neural system.

    That gives (a)-(iv), (b)-(ii), (c)-(iii), (d)-(i) — option 4.

    The trap: option 3 agrees with the answer on the first two pairs and swaps only the last two, so a student who checks the easy pairs first and stops will pick it. Check the pair you are least sure of before committing.

    NCERT Class 11 Biology, page 232

30. Q30 NEET 2018

    Match the following:

    Column I	Column II
    (a) Organ of Corti	(i) Coiled part of the labyrinth
    (b) Cochlea	(ii) Located on the basilar membrane
    (c) Eustachian tube	(iv) Attached to the oval window
    (d) Stapes	(iii) Connects the middle ear and pharynx

    1. 1.(a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)
    2. 2.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
    3. 3.(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)Correct answer
    4. 4.(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)

    Why option 3 is the answer

    The trap: Organ of Corti lies on the basilar membrane, cochlea is the coiled part of the labyrinth, the eustachian tube connects the middle ear and pharynx, and the stapes attaches to the oval window.

    What this is testing: four parts of the ear and where each sits.

    The organ of Corti lies on the basilar membrane. The cochlea is the coiled part of the labyrinth. The eustachian tube connects the middle ear with the pharynx. The stapes is attached to the oval window.

    That gives (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv) — option 3.

    The trap: option 1 pairs the organ of Corti with the coiled labyrinth, which is tempting because the organ of Corti does sit inside the cochlea. Being inside a structure is not the same as being that structure.

    NCERT Class 11 Biology, page 237