Question

In many animal cells, the uptake of glucose into the cell occurs by a cotransport mechanism, in which glucose is cotransported with Na ions. What is the mechanism of glucose uptake in animal cells?

1) Facilitated diffusion
2) Active transport
3) Endocytosis
4) Cotransport

Answer 1

In animal cells, glucose uptake occurs through cotransport, a form of secondary active transport that moves glucose into the cell against its concentration gradient with the help of sodium ions.

Step-by-step explanation:

The mechanism of glucose uptake in animal cells is known as cotransport, specifically a type of secondary active transport called symport. In this process, glucose is transported into the cell alongside sodium ions (Na+). The Na+/glucose symporter facilitates this movement: as Na+ moves down its electrochemical gradient into the cell (created by the Na+/K+ ATPase pump, which actively transports Na+ out of the cell and K+ into the cell using ATP), it carries glucose molecules with it against their concentration gradient into the cytoplasm. This cotransport system allows glucose to accumulate inside the cell, even when glucose concentrations are higher inside the cell than in the extracellular fluid, making this an active transport mechanism powered indirectly by ATP.