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10th Science MCQ PDF - All Chapters
NCERT Based MCQ with Explanation:
1. Which of the following nitrogenous wastes is the least toxic?
(A) Ammonia
(B) Urea
(C) Uric acid
(D) Creatinine
Explanation: Uric acid is the least toxic nitrogenous waste and requires minimal water for excretion, making it suitable for organisms in arid environments.
2. Ammonotelism is primarily observed in which group of animals?
(A) Mammals
(B) Birds
(C) Aquatic amphibians
(D) Reptiles
Explanation: Ammonotelic animals, such as aquatic amphibians and bony fishes, excrete ammonia due to its solubility in water.
3. Which organ is the primary site for the conversion of ammonia into urea in mammals?
(A) Kidney
(B) Liver
(C) Lungs
(D) Spleen
Explanation: The liver converts ammonia into urea through the urea cycle to reduce its toxicity for excretion via the kidneys.
4. Uricotelic animals excrete nitrogenous waste primarily as:
(A) Ammonia
(B) Urea
(C) Uric acid
(D) Allantoin
Explanation: Uricotelic animals, such as birds and reptiles, excrete uric acid, which is insoluble and requires minimal water.
5. What is the primary excretory product in ureotelic animals?
(A) Urea
(B) Ammonia
(C) Uric acid
(D) Bilirubin
Explanation: Ureotelic animals, including mammals, excrete urea as the main nitrogenous waste to conserve water.
6. What is the structural and functional unit of the kidney?
(A) Nephridia
(B) Glomerulus
(C) Nephron
(D) Renal tubule
Explanation: The nephron performs the essential functions of filtration, reabsorption, and secretion in the kidney.
7. The loop of Henle is primarily involved in:
(A) Filtration
(B) Concentration of urine
(C) Reabsorption of glucose
(D) Secretion of ammonia
Explanation: The loop of Henle establishes a counter-current mechanism essential for urine concentration.
8. Which part of the nephron is impermeable to water?
(A) Proximal convoluted tubule
(B) Descending limb of the loop of Henle
(C) Ascending limb of the loop of Henle
(D) Collecting duct
Explanation: The ascending limb is impermeable to water but actively transports salts.
9. What is the average glomerular filtration rate (GFR) in a healthy individual?
(A) 125 ml/min
(B) 90 ml/min
(C) 150 ml/min
(D) 200 ml/min
Explanation: GFR is the amount of filtrate formed per minute by the kidneys in a healthy individual.
10. What structure in the nephron monitors blood pressure and volume?
(A) Glomerulus
(B) Bowman’s capsule
(C) Juxta-glomerular apparatus (JGA)
(D) Vasa recta
Explanation: The JGA regulates GFR and blood pressure through the release of renin.
Science MCQ, Class 10th, Chapter-14, Sources Of Energy11. Which hormone increases water reabsorption in the kidneys?
(A) Aldosterone
(B) Antidiuretic Hormone (ADH)
(C) Renin
(D) Atrial Natriuretic Factor (ANF)
Explanation: ADH increases water reabsorption in the collecting ducts, reducing water loss in urine.
12. Which gland releases Aldosterone?
(A) Thyroid gland
(B) Adrenal cortex
(C) Hypothalamus
(D) Pancreas
Explanation: Aldosterone is secreted by the adrenal cortex and promotes sodium and water reabsorption in the kidney.
13. What is the primary function of the loop of Henle?
(A) Filtration of blood
(B) Concentration of urine
(C) Excretion of urea
(D) Secretion of hormones
Explanation: The loop of Henle creates an osmotic gradient for water reabsorption.
14. Which region of the nephron is highly coiled and responsible for reabsorption of nutrients?
(A) Proximal convoluted tubule (PCT)
(B) Loop of Henle
(C) Collecting duct
(D) Distal convoluted tubule (DCT)
Explanation: The PCT reabsorbs glucose, amino acids, and other essential nutrients.
15. What type of transport occurs for glucose reabsorption in the PCT?
(A) Passive diffusion
(B) Active transport
(C) Osmosis
(D) Facilitated diffusion
Explanation: Glucose is actively reabsorbed in the proximal convoluted tubule.
16. Which structure filters blood in the nephron?
(A) Glomerulus
(B) Bowman’s capsule
(C) Henle’s loop
(D) Collecting duct
Explanation: The glomerulus filters blood into the Bowman’s capsule.
17. What is the role of podocytes in the Bowman’s capsule?
(A) Blood filtration
(B) Reabsorption of water
(C) Secretion of ions
(D) Creating filtration slits
Explanation: Podocytes form filtration slits that allow selective passage of molecules.
18. Where does tubular secretion primarily occur?
(A) Proximal convoluted tubule
(B) Loop of Henle
(C) Distal convoluted tubule
(D) Collecting duct
Explanation: The DCT is involved in secreting ions like hydrogen and potassium.
19. Which substance is reabsorbed in the descending limb of the loop of Henle?
(A) Sodium
(B) Water
(C) Urea
(D) Glucose
Explanation: The descending limb is permeable to water, allowing its reabsorption.
20. The renal pelvis is directly connected to which structure?
(A) Ureter
(B) Urinary bladder
(C) Urethra
(D) Glomerulus
Explanation: The renal pelvis drains urine into the ureter.
21. Which part of the nephron is impermeable to electrolytes?
(A) Descending limb of the loop of Henle
(B) Ascending limb of the loop of Henle
(C) Collecting duct
(D) Bowman’s capsule
22. Which component of blood does not pass into the Bowman’s capsule during filtration?
(A) Glucose
(B) Sodium ions
(C) Plasma proteins
(D) Urea
23. What is the primary site of urea production in the body?
(A) Kidney
(B) Liver
(C) Spleen
(D) Intestine
24. What causes the release of renin by the juxta-glomerular apparatus?
(A) High blood pressure
(B) Low glomerular filtration rate
(C) High sodium levels
(D) Increased fluid intake
25. Which hormone opposes the renin-angiotensin mechanism?
(A) Antidiuretic Hormone (ADH)
(B) Aldosterone
(C) Atrial Natriuretic Factor (ANF)
(D) Cortisol
26. Which part of the nephron plays a crucial role in forming the medullary concentration gradient?
(A) Bowman’s capsule
(B) Loop of Henle
(C) Proximal convoluted tubule
(D) Distal convoluted tubule
27. What happens during tubular secretion?
(A) Reabsorption of water
(B) Filtration of blood
(C) Active addition of substances into the filtrate
(D) Passive transport of glucose
28. What does the counter-current mechanism in the kidney achieve?
(A) Acid-base balance
(B) Formation of dilute urine
(C) Concentration of urine
(D) Filtration of blood
29. Where is the juxta-glomerular apparatus located?
(A) At the junction of the glomerulus and proximal tubule
(B) Near the afferent arteriole and distal convoluted tubule
(C) In the collecting duct
(D) In the loop of Henle
30. What is the major excretory product of reptiles?
(A) Ammonia
(B) Urea
(C) Uric acid
(D) Carbon dioxide
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