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Homeostasis MCQs for MDCAT Practice

Biology section, Homeostasis chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 1,140 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    Which of the following is drought tolerant plant?
    • Wheat
    • Canola
    • Cotton
    • Sugarcane (correct answer)
    Correct answer: D
    Sugarcane stands out as a drought-tolerant crop due to its C4 photosynthetic pathway, enabling efficient water use.
  2. Question 2
    Mammalian kidney including human is adapted to conserve water by_____________reabsorption of glomerular filtrate.
    • 99.0%
    • 99.1%
    • 99.5%
    • Approximately 99.5% (correct answer)
    Correct answer: D
    The mammalian kidney conserves water by reabsorbing approximately 99.5% of glomerular filtrate, a crucial adaptation for maintaining fluid balance.
  3. Question 3
    ________ are animals that do not adjust their internal osmolality and are isotonic with their environment.
    • Osmoconformers (correct answer)
    • Osmoregulators
    • Thermoregulators
    • Thermoconformers
    Correct answer: A
    Osmoconformers passively match their internal salt concentration to their environment, unlike osmoregulators which actively control it.
  4. Question 4
    Which human peptide hormone acts directly on the collecting ducts of the nephrons to increase the reabsorption of water back into the bloodstream?
    • Aldosterone
    • Parathormone
    • Antidiuretic hormone (correct answer)
    • Oxytocin
    Correct answer: C
    Antidiuretic hormone (ADH) is a peptide hormone that directly triggers aquaporin insertion into collecting duct membranes to promote water reabsorption.
  5. Question 5
    The flame cells are the organs of excretionin
    • Planaria (correct answer)
    • Cockroach
    • Earthworm
    • Hydra
    Correct answer: A
    Flame cells are the primary excretory organs in Planaria, a type of flatworm, functioning as protonephridia to maintain osmotic balance.
  6. Question 6
    The components of feedback mechanism are ____________
    • Receptors, insulators, effectors
    • Receptors, suppressors, effectors
    • Receptors, depressors, effectors
    • Receptors, control center, effectors (correct answer)
    Correct answer: D
    Feedback mechanisms, vital for homeostasis, consist of receptors detecting stimuli, a control center processing information, and effectors responding to changes.
  7. Question 7
    The collecting tubule receives wastes from:
    • Renal Pelvis
    • Distal Tubule (correct answer)
    • Proximal Tubule
    • Loop of Henle
    Correct answer: B
    The collecting tubule primarily receives modified filtrate from the distal convoluted tubule, not directly from earlier parts of the nephron or the renal pelvis.
  8. Question 8
    The epidermis of the xerophytes is covered with a waxy layer called:
    • Cellulose
    • Cuticle (correct answer)
    • Chitin
    • Lignin
    Correct answer: B
    Xerophytes have a waxy cuticle on their epidermis to prevent water loss, a crucial adaptation for survival in arid environments.

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Read the full Homeostasis chapter notes: Homeostasis notes. Or browse every chapter.