Coordination & Control MCQs set 2 for King Edward Medical University Entry Test Biology — 20 solved questions.
Q1. A 45-year-old woman experiences a decreased metabolic rate, mental dullness, and puffiness of hands and face. Which condition is she likely suffering from?
Answer: Myxedema
Explanation: Myxedema results from thyroid underactivity in adults, causing puffiness. Graves' disease is the tempting wrong choice, but it involves hyperthyroidism.
Q2. A farm worker exposed to organophosphate pesticides shows muscle tremors and spasms due to inhibited acetylcholinesterase. What is the direct physiological result?
Answer: Continuous stimulation of the post-synaptic membrane
Explanation: Acetylcholinesterase breaks down acetylcholine; its inhibition leads to continuous stimulation. Acetylcholine synthesis is incorrect as the neurotransmitter is already present.
Q3. A potted plant placed near a window bends towards the light source. Which hormone is primarily responsible for this differential growth?
Answer: Auxins
Explanation: Auxins migrate to the dark side, causing cell elongation there. Gibberellins are tempting but primarily affect stem elongation via different mechanisms.
Q4. A patient with a brain tumor loses the ability to regulate body temperature and experiences disrupted sleep-wake cycles. Which region is affected?
Answer: Hypothalamus
Explanation: The hypothalamus acts as the body's thermostat and regulates sleep. The thalamus is tempting but serves as a sensory relay center.
Q5. A teenager is diagnosed with Type 1 Diabetes. Which hormone's deficiency is responsible for the high blood glucose levels observed in this patient?
Answer: Insulin
Explanation: Insulin promotes glucose uptake and glycogen synthesis. Glucagon is the opposite, increasing blood glucose levels during fasting states.
Q6. During a routine checkup, a doctor strikes the patellar tendon, causing the leg to kick. Which neuron first transmits the stimulus?
Answer: Sensory neuron
Explanation: In a reflex arc, the sensory neuron carries the impulse to the CNS. The motor neuron is tempting but carries the response away.
Q7. A hiker encounters a bear, causing an immediate increase in heart rate and dilation of the pupils. Which system is activated?
Answer: Sympathetic nervous system
Explanation: The sympathetic system prepares the body for 'fight or flight' by dilating pupils. The parasympathetic system constricts them during rest.
Q8. A patient presents with high blood pressure, muscle wasting, and a 'moon face' appearance due to adrenal cortex overactivity. What is the diagnosis?
Answer: Cushing's syndrome
Explanation: Cushing's syndrome involves excessive cortisol, causing a moon face. Addison's disease is tempting but involves a deficiency of adrenal hormones.
Q9. A grapevine tendril comes into contact with a wooden stake and begins to coil around it. This directional growth response is known as:
Answer: Haptotropism
Explanation: Haptotropism is a growth response to touch, such as climbing. Thigmonasty is tempting but is a non-directional turgor movement.
Q10. The speed of a nerve impulse is significantly increased in certain neurons due to the insulating fatty layer called the:
Answer: Myelin sheath
Explanation: Myelin sheaths act as insulators, allowing saltatory conduction. Nodes of Ranvier are where the impulse jumps, not the insulation itself.
Q11. A patient suffers from excessive thirst and produces large volumes of very dilute urine. This condition results from a deficiency of:
Answer: Antidiuretic hormone
Explanation: ADH increases water reabsorption; its lack causes dilute urine in Diabetes Insipidus. Diabetes Mellitus is tempting but involves glucose regulation.
Q12. An elderly man exhibits involuntary tremors and a mask-like face due to the degeneration of dopamine-producing neurons. Which disorder is this?
Answer: Parkinson's disease
Explanation: Parkinson's is caused by the death of dopamine-producing neurons. Alzheimer's is tempting but involves acetylcholine deficiency and memory loss.
Q13. A researcher applies a hormone to a cabbage plant, causing it to undergo rapid stem elongation before flowering. Which hormone was used?
Answer: Gibberellins
Explanation: Gibberellins induce 'bolting' or rapid stem elongation in rosette plants. Auxins are tempting but primarily control apical dominance.
Q14. After a head injury, a gymnast is unable to maintain balance and shows jerky, uncoordinated movements. Which part of the brain is damaged?
Answer: Cerebellum
Explanation: The cerebellum coordinates complex voluntary movements and balance. The cerebrum is tempting but handles higher-order thinking and sensory perception.
Q15. A patient develops increased excitability of nerves and painful muscular spasms after the accidental removal of the parathyroid glands. This is:
Answer: Tetany
Explanation: Low blood calcium (hypocalcemia) leads to tetany and muscle twitching. Hypercalcemia is tempting but results from overactive parathyroid glands.
Q16. Certain sedative drugs work by enhancing the effect of an inhibitory neurotransmitter. Which of the following is an inhibitory neurotransmitter?
Answer: GABA
Explanation: GABA is the primary inhibitory neurotransmitter in the CNS. Adrenaline is tempting but is typically an excitatory neurotransmitter.
Q17. During a severe drought, a plant prevents excessive water loss by closing its stomata. Which hormone mediates this stress response?
Answer: Abscisic acid
Explanation: Abscisic acid (ABA) promotes stomatal closure during water stress. Ethene is tempting but is primarily involved in fruit ripening.
Q18. A 14-year-old boy begins to develop secondary sexual characteristics. Which cells in the testes are responsible for secreting the necessary hormone?
Answer: Interstitial cells
Explanation: Interstitial (Leydig) cells produce testosterone. Sertoli cells are tempting but provide nourishment to developing sperm cells.
Q19. A stroke patient can feel touch but cannot localize where it is coming from on the body. Which sensory relay center is likely affected?
Answer: Thalamus
Explanation: The thalamus relays all sensory information except smell to the cerebrum. The hypothalamus is tempting but focuses on homeostasis.
Q20. A farmer places a few ripe bananas in a crate of green mangoes to speed up their ripening. Which gas is responsible?
Answer: Ethene
Explanation: Ethene (ethylene) is a gaseous hormone that triggers fruit ripening. Cytokinin is tempting but is involved in cell division.