A 45-year-old patient has abnormally high blood glucose despite insulin administration. Which condition is most likely?
Answer: B
Type 2 diabetes involves insulin resistance where cells don't respond properly to insulin, maintaining elevated blood glucose despite insulin presence.
Q.82Medium
Which of the following correctly describes the role of the cerebellum in motor control?
Answer: B
The cerebellum compares intended movements with actual movements, providing real-time corrections for coordination, balance, and fine motor control.
Q.83Medium
In the cardiac cycle, what occurs during the isovolumetric contraction phase?
Answer: B
During isovolumetric contraction, ventricular volume stays constant while pressure rapidly increases as both AV and semilunar valves are closed.
Q.84Medium
A marathon runner experiences 'hitting the wall' around 20km. This is primarily due to:
Answer: B
Glycogen depletion in muscles and liver reduces glucose availability for ATP production, causing sudden fatigue despite continued oxygen availability.
Q.85Medium
In synaptic transmission, what is the role of monoamine oxidase (MAO)?
Answer: B
MAO degrades monoamines (dopamine, serotonin, norepinephrine) in mitochondria of presynaptic terminals, regulating neurotransmitter levels.
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Q.86Medium
In the auditory system, how does the cochlea convert sound vibrations into neural signals?
Answer: B
Stapes vibrations move perilymph in the cochlea, causing basilar membrane displacement and stereocilia bending on hair cells, generating action potentials.
Q.87Medium
Which statement accurately describes the relationship between respiratory rate and blood CO2 levels?
Answer: B
Central and peripheral chemoreceptors detect increased CO2 (and decreased pH), sending signals to respiratory centers to increase ventilation rate.
Q.88Medium
A patient with severe dehydration experiences increased blood osmolarity. Which hormone is primarily released to counteract this condition?
Answer: B
ADH (vasopressin) is released in response to increased blood osmolarity, increases aquaporin-2 channels in collecting ducts, and promotes water reabsorption.
Q.89Medium
During the refractory period following an action potential, why is it difficult to generate another action potential?
Answer: B
During the refractory period, sodium channels enter an inactivated state (unable to reopen immediately) while potassium channels remain open, hyperpolarizing the membrane.
Q.90Medium
A student experiences increased heart rate and dilated pupils during an exam. Which division of the autonomic nervous system is responsible?
Answer: B
The sympathetic nervous system triggers 'fight or flight' responses including increased heart rate and pupil dilation via norepinephrine and epinephrine.
Q.91Medium
The countercurrent multiplier mechanism in the Loop of Henle is essential for:
Answer: B
The countercurrent multiplier creates an osmotic gradient allowing the production of concentrated urine by establishing osmolarity differences in the medulla.
Q.92Medium
During inspiration, which of the following occurs?
Answer: B
During inspiration, external intercostal muscles contract, increasing thoracic volume, decreasing intrapleural pressure, and allowing air to flow into lungs.
Q.93Medium
A mutation in the genes encoding dystrophin protein leads to:
Answer: B
Dystrophin is a structural protein that stabilizes muscle cell membranes; its absence causes Duchenne muscular dystrophy with progressive muscle weakness.
Q.94Medium
Which of the following best explains how the human body maintains stable internal temperature despite environmental changes?
Answer: B
The hypothalamus acts as the body's thermostat, detecting temperature changes and triggering responses (sweating, vasoconstriction) through negative feedback mechanisms.
Q.95Medium
During exercise, what is the primary mechanism by which muscles obtain additional oxygen?
Answer: A
Exercise triggers increased respiratory and heart rates, enhancing oxygen delivery to muscles through elevated blood flow and ventilation.
Q.96Medium
Which hormone is essential for maintaining calcium homeostasis and is activated by low blood calcium levels?
Answer: B
PTH is secreted by parathyroid glands in response to hypocalcemia, increases calcium reabsorption in kidneys, and promotes calcium mobilization from bones.
Q.97Medium
A patient exhibits symptoms of excessive thirst, frequent urination, and fatigue. Blood tests reveal elevated glucose levels and reduced insulin secretion. Which pancreatic cells are primarily affected in this condition?
Answer: B
The symptoms (polydipsia, polyuria, fatigue) along with elevated blood glucose and reduced insulin indicate Type 1 diabetes mellitus, where autoimmune destruction of pancreatic beta cells occurs, reducing insulin production.
Q.98Medium
Which of the following statements about the human kidney's counter-current multiplier system is correct?
Answer: B
The counter-current multiplier system in the loop of Henle (particularly the thick ascending limb) creates an osmotic gradient that enables water reabsorption in the collecting duct, essential for urine concentration.
Q.99Medium
In pea plants, round seeds (R) are dominant over wrinkled seeds (r). If a plant with round seeds is crossed with a wrinkled seed plant and produces 50% round and 50% wrinkled seeds, the genotype of the round seed plant is:
Answer: B
The 1:1 ratio indicates a testcross result (Rr × rr). The round seed parent must be heterozygous (Rr) to produce wrinkled (rr) offspring.
Q.100Medium
Which of the following represents the correct order of organization in genetic material?
Answer: C
The correct hierarchical order is: Nucleotide (basic unit) → DNA (polymer of nucleotides) → Gene (segment of DNA) → Chromosome (condensed DNA with proteins).
