NEET (UG)

Practice Test 1 — Excretory Products and their Elimination

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

The least toxic nitrogenous waste, needing the least water, is:

Solution: Uric acid is least toxic and conserves water.

Question 2

Insects and birds are:

Solution: They are uricotelic.

Question 3

The Malpighian corpuscle consists of the glomerulus and the:

Solution: Glomerulus + Bowman's capsule = Malpighian corpuscle.

Question 4

The glomerular filtration rate is approximately:

Solution: GFR ≈ 125 mL/min (~180 L/day).

Question 5

Most of the glomerular filtrate is reabsorbed in the:

Solution: The PCT reabsorbs most of the filtrate.

Question 6

The counter-current mechanism is associated with the:

Solution: The Loop of Henle + vasa recta build the medullary gradient.

Question 7

ADH is secreted by the:

Solution: ADH is released from the posterior pituitary.

Question 8

Uraemia is treated by:

Solution: Haemodialysis removes accumulated urea from the blood.

Section B — Assertion & Reason

Question 9

A: Uricotelic animals lose very little water in excretion.
R: Uric acid is almost insoluble and is excreted as a near-solid paste.

Solution: Excreting insoluble uric acid needs minimal water — R explains A.

Question 10

A: Although ~180 L of filtrate forms daily, only ~1.5 L of urine is produced.
R: About 99% of the glomerular filtrate is reabsorbed in the tubules.

Solution: Massive reabsorption (~99%) is why output is tiny — R explains A.

Question 11

A: ADH causes a person to produce large volumes of dilute urine.
R: ADH promotes the reabsorption of water from the distal tubule and collecting duct.

Solution: A is false — ADH causes LESS, more concentrated urine (it is antidiuretic); R correctly states it promotes water reabsorption.

Question 12

A: The descending limb of the Loop of Henle concentrates the filtrate.
R: It is permeable to water, which leaves the filtrate as it passes through the hypertonic medulla.

Solution: Water leaving the water-permeable descending limb concentrates the filtrate — R explains A.