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Difficulty: Very hardHormonal Coordination in Plants and Animals

Match each plant or animal hormone in Column I with its corresponding primary physiological action or cellular mechanism in Column II.

  • Abscisic Acid (ABA)Induces rapid stomatal closure during water deficit by triggering potassium ion efflux from guard cells
  • AldosteronePromotes sodium ion reabsorption and potassium ion secretion in the distal renal tubules
  • CytokininStimulates cell division and delays leaf senescence by mobilizing nutrients
  • Parathyroid Hormone (PTH)Increases blood calcium levels by stimulating osteoclast activity and enhancing renal calcium reabsorption

Answer

Abscisic Acid pairs with inducing rapid stomatal closure via potassium efflux; Aldosterone pairs with promoting sodium reabsorption and potassium secretion in distal renal tubules; Cytokinin pairs with stimulating cell division and delaying leaf senescence; Parathyroid Hormone pairs with increasing blood calcium levels by activating osteoclasts and enhancing renal calcium reabsorption.
Abscisic acid causes stomatal closure during drought through potassium ion loss from guard cells. Aldosterone regulates osmoregulation by increasing renal sodium uptake and potassium excretion. Cytokinins stimulate cytokinesis and delay aging in plant leaves. Parathyroid hormone increases extracellular calcium concentration through bone resorption by osteoclasts and renal retention.

Step-by-Step Solution

1
Identify the primary mechanism of Abscisic Acid
Abscisic Acid acts as a stress plant growth regulator, mediating stomatal closure during drought via guard cell K+K^+ efflux.
Prevents transpirational water loss in plants under hydric stress.
2
Identify the primary function of Aldosterone
Aldosterone targets distal convoluted tubules and collecting ducts in nephrons to reabsorb Na+Na^+ while secreting K+K^+.
Maintains electrolyte balance and blood volume homeostasis in animals.
3
Identify the physiological role of Cytokinin
Cytokinins stimulate cell division in root and shoot meristems and retard chlorophyll breakdown in leaves.
Promotes growth and prevents premature tissue aging.
4
Identify the endocrine action of Parathyroid Hormone
PTH raises serum Ca2+Ca^{2+} concentration by mobilizing bone calcium through osteoclast activity and stimulating renal tubule reabsorption.
Counteracts hypocalcemia to maintain calcium homeostasis.

Key Concept

Mechanisms of hormonal regulation and cellular responses in plant and animal systems
Estimated Time:2m 0s
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Topics

Hormonal Coordination in Plants and Animals

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