Which of the following is responsible for water transport down an osmotic gradient during oocyte maturation?

Correct option is A

→ Aquaporins are water channel proteins allowing rapid water influx into maturing oocytes along osmotic gradients.
→ Crucial during final oocyte hydration, especially in marine fishes.
→ Increases egg buoyancy and prepares the oocyte for spawning.
Information Booster:
→ Hydration expands the oocyte volume several times.
→ Regulated by maturation-inducing hormones such as 17α,20β-DHP.
→ Essential for fertilization success in pelagic spawners.
Additional Information (Other Options):
(b) Vitellogenin: Yolk precursor, not water transport.
(c) Progesterone: Maturation-inducing but not a water channel.
(d) Clathrin: Vesicle coating protein, not involved in osmotic water flow.