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Insulin raises glucose uptake mainly through which cellular action?

AIt carries glucose across the membrane itself
BIt moves transporter vesicles to the membrane
CIt opens voltage-gated channels in the membrane
DIt builds new transporters inside the nucleus
Answer & Solution
Correct answer: B. It moves transporter vesicles to the membrane
1. Facilitative glucose transporters sit in intracellular vesicles when insulin is absent. 2. Without insulin those vesicles are recycled only slowly between membrane and cell interior. 3. Insulin triggers rapid movement of a pool of these vesicles to the cell membrane. 4. The vesicles fuse and expose their transporters to the extracellular fluid. 5. Glucose then enters by facilitated diffusion through the newly exposed transporters. 6. Insulin is a signal, not a carrier, so it never ferries glucose across the membrane and does not open a voltage-gated channel. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 17 "The Endocrine System", section 17.9 The Endocrine Pancreas_
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