Control and Coordination

The structural and functional unit of the nervous system is the:

1. aNephron
2. bAlveolus
3. cNeuron
4. dSynapse

The plant hormone responsible for promoting cell division (especially in fruits) is:

1. aAuxin
2. bCytokinin
3. cGibberellin
4. dAbscisic acid

When you suddenly touch a hot object, you withdraw your hand even before you 'know' it. Which is the correct sequence of structures involved?

1. aReceptor -> brain -> spinal cord -> motor neuron -> effector
2. bReceptor -> sensory neuron -> brain -> motor neuron -> effector
3. cEffector -> motor neuron -> spinal cord -> sensory neuron -> receptor
4. dReceptor -> sensory neuron -> spinal cord (relay neuron) -> motor neuron -> effector

A pituitary tumour is found to over-secrete growth hormone in an 8-year-old boy. The expected outcome is:

1. aDwarfism
2. bNo effect on growth
3. cStunted height with normal weight
4. dGigantism (excessive height growth)

Which of the following is NOT a function of the cerebellum?

1. aMaintaining balance
2. bCoordinating skilled movements
3. cControlling heart rate and breathing
4. dCoordinating limb position during walking

A scientist applies a chemical that blocks the GAP between adjacent neurons. The MOST IMMEDIATE effect on signalling will be:

1. aFaster reflexes due to more direct nerve transmission
2. bFailure of the impulse to cross from one neuron to the next, breaking the chain
3. cHigher hormone secretion to compensate for the loss
4. dConversion of nerve impulses into chemical hormones

Which structure controls involuntary actions like blinking, salivation and vomiting?

1. aCerebrum
2. bCerebellum
3. cHypothalamus
4. dMedulla oblongata

If a person's diet is deficient in iodine for a long period, the most likely consequence is:

1. aDiabetes
2. bExcess production of insulin
3. cGoitre (enlarged thyroid gland) due to inability to make thyroxine
4. dSudden gigantism

Assertion (A): Reflex actions are faster than voluntary responses involving the brain.

Reason (R): Reflex arcs evolved as a quick way to respond to harmful stimuli without waiting for slower processing in the brain.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): Iodine is essential for normal functioning of the thyroid gland.

Reason (R): Iodine is essential for the synthesis of thyroxine, the hormone that regulates the body's basal metabolic rate.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): A potted plant placed near a window with light coming from one side bends its stem towards the light.

Reason (R): Auxin is synthesised at the shoot tip and migrates to the side away from the light, where it causes greater cell elongation, bending the stem towards light.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): A person experiences increased heart rate, faster breathing and dilation of pupils when frightened.

Reason (R): Adrenaline acts on the heart, blood vessels and other organs to prepare the body for fight or flight by increasing heart rate, breathing rate and glucose supply.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

1. I. A reflex action is a quick, involuntary response to a stimulus that does not require conscious thought.
2. II. A change in the size of the pupil when bright light falls on the eyes is an example of a simple reflex action.

Which of the above is/are correct?

1. aOnly I
2. bBoth I and II
3. cOnly II
4. dNeither I nor II

1. I. The cerebrum is the largest part of the brain and is responsible for thinking, memory and voluntary actions.
2. II. The cerebellum maintains balance and coordination of muscular movements.
3. III. The medulla controls involuntary actions such as breathing, heart rate and blood pressure.

Regarding parts of the brain, which of the above is/are correct?

1. aOnly I and II
2. bOnly II and III
3. cOnly I and III
4. dI, II and III

1. I. A plant shoot bends towards light because of the unequal distribution of auxin around the stem tip.
2. II. Auxin gets concentrated on the side of the stem AWAY from the light, causing more elongation on that side.

Regarding phototropism in plants, which of the above is/are correct?

1. aOnly I
2. bOnly II
3. cBoth I and II
4. dNeither I nor II

1. I. Insulin is secreted by the pancreas and lowers blood glucose levels.
2. II. Diabetes mellitus can result from deficient insulin secretion or reduced action of insulin on body tissues.
3. III. Adrenaline released during fear or stress decreases the heart rate and slows breathing.

Regarding insulin and adrenaline, which of the above is/are correct?

1. aOnly I
2. bOnly I and II
3. cOnly II and III
4. dOnly I and III

Match the hormone with its source gland:

1. a(i)-Q, (ii)-P, (iii)-S, (iv)-R
2. b(i)-Q, (ii)-S, (iii)-P, (iv)-R
3. c(i)-P, (ii)-S, (iii)-Q, (iv)-R
4. d(i)-Q, (ii)-S, (iii)-R, (iv)-P

Match the plant hormone with its action:

1. a(i)-S, (ii)-R, (iii)-P, (iv)-Q
2. b(i)-P, (ii)-Q, (iii)-R, (iv)-S
3. c(i)-R, (ii)-S, (iii)-P, (iv)-Q
4. d(i)-R, (ii)-P, (iii)-S, (iv)-Q

Match the brain part with its primary role:

1. a(i)-Q, (ii)-S, (iii)-P, (iv)-R
2. b(i)-P, (ii)-Q, (iii)-R, (iv)-S
3. c(i)-R, (ii)-Q, (iii)-S, (iv)-P
4. d(i)-Q, (ii)-R, (iii)-P, (iv)-S

A pea plant in a kitchen garden grows near a wire fence. One of its tendrils touches the wire and, over a few days, coils around it. What causes the coiling?

1. aThe part of the tendril touching the wire grows faster than the part away from it
2. bThe part of the tendril touching the wire grows more slowly than the part away from it
3. cCells of the tendril lose water and shrink at once, as in the leaves of the sensitive plant
4. dThe tendril grows towards the light falling on the wire

A diabetic patient skips meals and then takes their usual insulin injection. Within 30 minutes they feel weak, sweaty, and confused. The MOST LIKELY chemical cause is:

1. aInsulin breaking down in the bloodstream
2. bExcess glucose in muscles
3. cHypoglycaemia (very low blood glucose) because insulin lowered glucose without food intake to balance it
4. dAdrenaline overproduction

A bean seed sprouts in a covered pot. The shoot grows upward and the root grows downward, regardless of the orientation of the pot. The MAIN explanation is:

1. aThe shoot is positively phototropic and the root is negatively phototropic
2. bThe shoot is positively geotropic and the root is negatively geotropic
3. cPlants do not respond to gravity at all
4. dThe shoot is negatively geotropic (grows away from gravity) and the root is positively geotropic (grows towards gravity)

Which gland is known as the 'master gland'?

1. aPituitary
2. bThyroid
3. cAdrenal
4. dPancreas

What is the role of the synaptic cleft in nerve impulse transmission?

1. aIt physically conducts the electrical impulse without a chemical messenger
2. bIt manufactures hormones
3. cIt blocks unwanted electrical signals
4. dIt is the gap across which neurotransmitter molecules diffuse from one neuron to the next

Which of the following pairs of plant responses is correctly matched?

1. aPhototropism — response to light
2. bGeotropism — response to chemicals
3. cHydrotropism — response to gravity
4. dChemotropism — response to water

How are plants able to respond to stimuli without a nervous system?

1. aThey use chemical signals (plant hormones) and changes in cell turgor
2. bThey have a hidden nervous system in their roots
3. cThey have organs analogous to muscles that contract
4. dThey have neurons in their leaves

Why does the body NEED both a nervous system AND an endocrine (hormonal) system?

1. aBoth do exactly the same thing — having two is redundant
2. bNervous: rapid, short-lived, localised; hormonal: slow, sustained, widespread — together they cover all timescales
3. cThe endocrine system is a backup that activates only when nerves fail
4. dThe nervous system handles plants and the endocrine system handles animals

Which of the following correctly states a feature of HORMONES from the passage?

1. aThey travel through dedicated ducts to reach target organs
2. bThey are released only during emergencies
3. cThey are secreted by ductless glands directly into the bloodstream
4. dThey cause electrical impulses in nerves

If a small amount of adrenaline is injected into a calm person, the IMMEDIATE physiological responses MOST LIKELY observed include:

1. aIncreased glucose absorption into fat cells
2. bLowered heart rate, slower breathing, constriction of pupils
3. cNo change because adrenaline acts only during fear
4. dIncreased heart rate, increased breathing rate, dilation of pupils

Which of the following is the BEST contrast between plant and animal control systems?

1. aBoth have nervous systems but plants' is hidden
2. bPlants use only hormones; animals use both nervous and endocrine systems
3. cPlants have neurons in their stem; animals do not
4. dAnimals do not produce hormones, only neurotransmitters