NEET Biology: Modes of excretion-ureotelism Practice Questions
15 free multiple-choice questions on Modes of excretion-ureotelism (Excretory Products and their elimination) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. In invertebrates, such as insects, the primary excretory product is typically excreted as which form?
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Correct answer: B — Ammonia
Many invertebrates, including insects, excrete nitrogen primarily in the form of ammonia, which is then excreted, though some may convert it to uric acid depending on the species and environment.
Q2. Which organ is the principal excretory organ responsible for eliminating nitrogenous waste in humans?
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Correct answer: B — Kidney
The kidneys filter the blood and excrete nitrogenous waste in the form of urine.
Q3. The formation and elimination of urine is a crucial excretory function carried out by which structure?
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Correct answer: A — Nephron (part of the Kidney)
The nephrons in the kidney are responsible for filtering blood and eliminating waste products to form urine.
Q4. In the context of ureotelism, what is the primary function of excreting urea in animals?
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Correct answer: C — To maintain osmotic balance
Urea is highly soluble and allows for the excretion of nitrogenous waste in a water-soluble form, which is crucial for maintaining the body's osmotic balance and water regulation.
Q5. Which organ is chiefly responsible for the final elimination of urea from the blood into the urine?
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Correct answer: C — Kidneys
The kidneys filter the blood and facilitate the excretion of urea into the urine, which is the mechanism for elimination.
Q6. Which amino acid is the primary precursor for the synthesis of urea in mammals?
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Correct answer: C — Aspartate
Aspartate is a key intermediate in the urea cycle. It is converted into carbamoyl phosphate, initiating the process that leads to urea formation in the liver.
Q7. What is the metabolic fate of ammonia after it is produced in amino acid catabolism, which is critical before urea formation?
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Correct answer: B — It is incorporated into the urea cycle.
Ammonia is toxic; it must be incorporated into the urea cycle, starting with the entry points (like carbamoyl phosphate synthesis), to be detoxified into urea.
Q8. Which organ is primarily responsible for the synthesis of urea from amino acid breakdown products in mammals?
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Correct answer: D — Liver
The liver is the principal site for deamination of amino acids, and subsequently, the urea cycle operates primarily in the liver to detoxify ammonia into urea.
Q9. Urea is considered a highly soluble compound, which aids in its efficient elimination. What is the role of water in the process of ureotelism?
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Correct answer: C — To act as the solvent for urea and facilitate its excretion
Water acts as the solvent for urea, allowing it to be dissolved and transported effectively through the renal tubules for excretion.
Q10. The process of ureotelism involves the breakdown of which molecule to facilitate the excretion of nitrogenous wastes?
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Correct answer: A — Amino acids
Nitrogenous wastes are derived from the breakdown of amino acids; thus, the breakdown of amino acids is the precursor to the formation of urea.
Q11. The final excretory product of the nitrogenous waste in the human excretory system is primarily:
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Correct answer: A — Urea
Urea is the main compound in which nitrogenous waste is excreted in urine.
Q12. What is the primary source of nitrogenous waste that requires elimination through the excretory system in most animals?
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Correct answer: C — Ammonia
Amino acid breakdown releases ammonia, which is subsequently converted into urea for excretion. Ammonia is highly toxic and must be eliminated.
Q13. The elimination of metabolic waste products through the excretory system is crucial for maintaining which physiological state?
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Correct answer: A — Homeostasis
Excretion helps maintain the internal environment, which is the definition of homeostasis, by removing excess metabolic byproducts.
Q14. In mammals, the primary mode of nitrogenous waste elimination, known as ureotelism, involves the conversion of highly toxic ammonia into which excretory product?
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Correct answer: D — Urea
Ureotelism is the process where mammals convert toxic ammonia (derived from amino acid metabolism) into urea, which is then excreted by the kidneys.
Q15. Urea is considered a relatively non-toxic waste product primarily because it is highly water-soluble. This property is essential for which physiological process?
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Correct answer: D — Maintaining osmotic homeostasis
Its high water solubility allows urea to be easily transported and excreted via urine, which is vital for maintaining the body's overall osmotic balance.
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