Top 25+ Excretory Products and Their Elimination - Biology Questions and Answers For NEET 2024 Exam Preparation

Q1. Which one of the following options gives the correct categorization of six animals according to the type of nitrogenous waste they give out?

Answer: (c)

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Q2. Filtration fraction is the ratio of

1. haemoglobin to oxyhaemoglobin
2. glomerular filtration rate (GFR) to renal plasma flow (RPF)
3. glomerular filtrate to urine
4. $O_{2}$ to $CO_{2}$

Answer: (b)

Filtration fraction is the ratio of the glomerular filtration rate (GFR) to the renal plasma flow (RPF)

i.e., FF = GFR/RPF.

The filtration fraction, therefore, represents the proportion of the fluid reaching the kidneys which passes into the renal tubules.

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Q3. In nephron water absorption is maximum in

1. descending limb of Henle.
2. proximal convoluted tubule (PCT).
3. ascending limb of Henle.
4. distal convoluted tubule (DCT).

Answer: (b)

PCT increases the surface area for reabsorption. PCT reabsorbs most of the nutrients, and 70-80% of electrolytes and water.

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Q4. Which of the following is correctly matched with its function of a specific part of a human nephron?

1. Henle’s loop – Reabsorption of the major substances from the glomerular filtrate.
2. Afferent arteriole – Carries the blood away from the glomerulus towards renal vein.
3. Podocytes – Create minute spaces (slit pores) for the filtration of blood into the Bowman’s capsule.
4. Distal convoluted tubule – Reabsorption of K+ ions into the surrounding blood capillaries.

Answer: (c)

Afferent arterioles enters the glomerulus at the vascular pole and divides into capillaries which subsequently merge to form efferent arterioles. Henle's loop has minimum reabsorption. It plays a significant role in the maintenance of osmolarity of the medullary interstitial fluid. i.e concentration of urine.

In Distal convoluted tubules reabsorption of water and sodium takes place. It is also capable of reabsorption of HCO3– and selective secretion of hydrogen and potassium ions.

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Q5. Which of the following is likely to accumulate in dangerous proportion in the blood of a person whose kidney is not working properly?

1. Lysine
2. Ammonia
3. Urea
4. Sodium chloride

Answer: (c)

One of the most important things the kidneys excrete nitrogenous waste. As the liver breaks down amino acids it also releases ammonia. The liver then quickly combines that ammonia with carbon dioxide, creating urea which is the primary nitrogenous end product of metabolism in humans.

The liver turns the ammonia into urea because it is much less toxic. Therefore, urea is likely to accumulate in dangerous proportion in the blood of a person whose kidney is not working properly.

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Q6. Ammonia which is produced by metabolism is converted into _____A______ in the liver of mammals and released into ______B_____ which is filtered and _____C______ out by kidney

1. A– Urea, B– Blood, C– excreted
2. A– Uric acid, B– Blood, C– excreted
3. A– Amino acid, B– Blood, C– excreted
4. A– Sugar, B– Blood, C– excreted

Answer: (a)

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Q7. Which of the following segment allows the passage of small amount of urea into modularly interstitium to keep up the osmolarity?

1. DCT
2. PCT
3. HL
4. Collecting duct

Answer: (d)

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Q8. Atrial natriuretic factor (ANF) is released in response to the increase in blood volume and blood pressure. Which of the following is not the function of ANF?

1. Stimulates salt loss in urine
2. Stimulates aldosterone secretion
3. Inhibits the release of renin from JGA
4. Inhibits sodium reabsorption from collecting duct

Answer: (b)

ANF stimulates the loss of sodium in urine while aldosterone absorbs sodium from glomerular filtrate.

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Q9. Removal of proximal convoluted tubule from the nephron will result in:

1. No urine formation
2. More concentrated urine
3. No change in quality and quantity of urine
4. More diluted urine

Answer: (d)

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Q10. A large quantity of one of the following is removed from our body by lungs.

1. $H_{2}$O only
2. $CO_{2}$ only
3. $CO_{2}$ and $H_{2}$O
4. ammonia

Answer: (c)

Human lungs remove large amounts of $CO_{2}$ (18L / day)and also significant amount of water everyday. While respiration, $CO_{2}$ alone cannot be eliminated from the body and the same holds true for H2O. Ammonia is highly toxic, and thus it is immediately converted to a non-toxic form.

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Q11. A person who is on a long hunger strike and is surviving only on water, will have –

1. less urea in his urine
2. less amino acids in his urine
3. more glucose in his blood
4. more sodium in his urine

Answer: (a)

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Q12. Which of the following is Ureotelic?

1. Most of the terrestrial amphibians
2. Mammals
3. Marine fishes
4. All the above

Answer: (d)

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Q13. Aquatic animals are mostly ammonotelic because

1. Excretion of ammonia requires large amount of water which is available to these animals.
2. Ammonia helps in checking the inflow of water into body.
3. Water contains less nitrogen.
4. These get less light.

Answer: (a)

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Q14. The projections of renal pelvis are called

1. Calyces
2. Hiluses
3. Medullary pyramids
4. Renal columns

Answer: (a)

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Q15. Select the option which shows correct matching of animal with its excretory organ and excretory product.

Answer: (b)

In salamander, kidneys (mesonepheric) are the excretory organs and the excretory matter is urea. In Labeo, mesonephric kidney is the excretory organ and excretion is ammonotelic. Peacock has metanephric kidneys with excretory matter being uric acid. In housefly, excretion takes place by Malpighian tubules. Excretory waste is uric acid chiefly.

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Q16. Uricotelic mode of excreting nitrogenous wastes is found in

1. amphibians and reptiles
2. reptiles and birds
3. birds and annelids
4. insects and amphibians

Answer: (b)

Reptiles, birds, land snails and insects excrete nitrogenous wastes as uric acid in the form of pellet or paste with a minimum loss of water and are called uricotelic animals.

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Q17. Uric acid is the chief nitrogenous component of the excretory products of

1. Man
2. Cockroach
3. Frog
4. Earthworm

Answer: (b)

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Q18. Which one of the following statements is correct with respect to kidney function regulation?

1. An increase in glomerular blood flow stimulates the formation of angiotensin II.
2. Exposure to cold temperature stimulates ADH release.
3. During summer when the body loses lot of water by evaporation, the release of ADH is suppressed.
4. When someone drinks lot of water the ADH release is suppressed.

Answer: (d)

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Q19. Select the total number of excretory organ from the following found in various animals:
Protonephridia, SA node, nephridia, Hepatic Cecae, atrium, Malpighian tubules, green glands, kidney, pons, ommatidia, parapodia

1. 5
2. 4
3. 6
4. 7

Answer: (a)

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Q20. The ornithine cycle removes two waste products from the blood in liver. These products are

1. $CO_2$ and urea
2. $CO_2$ and ammonia
3. ammonia and uric acid
4. ammonia and urea.

Answer: (b)

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Q21. Which of the following causes an increase in sodium reabsorption in the distal convoluted tubule?

1. Decrease in aldosterone levels
2. Increase in aldosterone levels
3. Increase in antidiuretic hormone levels
4. Decrease in antidiuretic hormone levels

Answer: (b)

Aldosterone is a hormone secreted by the outer layer of the adrenal gland (cortex part). Decreased blood volume and interstitial fluid level, resulting in decreased blood pressure, trigger aldosterone secretion.

When aldosterone is present in the blood, reabsorption of $Na^{+}$ in the filtrate is increased by the epithelial cells of the collecting duct. Retaining $Na^{+}$ , raises the osmotic pressure of the blood and reduces water loss from the body.

When aldosterone is absent, some $Na^{+}$ remains in the filtrate and is excreted with the urine.

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Q22. Assertion: Ammonia is the excretory product of aquatic amphibian.

Reason: Ammonia is readily soluble in water and requires large amount of water for excretion.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (b)

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Q23. Which of the following statements is correct?

1. The descending limb of loop of Henle is permeable to electrolytes.
2. The descending limb of loop of Henle is impermeable to water.
3. The ascending limb of loop of Henle is permeable to water.
4. The ascending limb of loop of Henle is impermeable to water.

Answer: (d)

Descending limb of loop of Henle is permeable to water but impermeable to electrolytes. Ascending limb of loop of Henle is impermeable to water but permeable to electrolytes.

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Q24. Which one of the four parts mentioned below does not constitute a part of single uriniferous tubule?

1. Bowman's capsule
2. Distal convoluted tubule
3. Collecting duct
4. Loop of Henle

Answer: (c)

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Q25. Ultrafiltration occurs in a glomerulus when

1. capsular hydrostatic pressure exceeds glomerular hydrostatic pressure.
2. hydrostatic pressure exceeds osmotic pressure.
3. osmotic pressure exceeds hydrostatic pressure.
4. colloidal osmotic pressure plus capsular pressure remain less than glomerular hydrostatic pressure.

Answer: (d)

Ultrafiltration is an entirely passive process. It occurs in glomerulus when colloidal osmotic pressure plus capsular pressure remain less than glomerular hydrostatic pressure.

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