What makes a carrier a symporter?

• It couples movement in the same direction
• It couples movement in opposite directions
• It carries one substance without a coupled partner

Which protein uses ATP directly during sodium-dependent glucose entry into a gut lining cell?

• The sodium glucose symporter during coupled entry
• The sodium potassium pump during sodium export
• A glucose carrier during downhill glucose movement

Which substance moves down its electrochemical gradient through the gut sodium glucose symporter?

• Potassium ions
• Glucose molecules
• Sodium ions

A cell starts without a sodium gradient. Which sequence lets the pump support glucose entry against its concentration gradient?

• Symporter uses ATP; glucose entry then powers sodium export
• Glucose enters alone; its entry then builds the sodium gradient
• Pump uses ATP; its gradient then supports coupled entry

The sodium potassium pump is blocked. As the sodium gradient weakens, what happens to sodium-dependent glucose entry?

• It decreases as the gradient supplies less energy
• It increases as the symporter starts using saved ATP
• It stays unchanged because the gradient has no role

An antiporter couples entry of substance X to movement of substance Y across the same membrane. Which movement of Y accompanies X entering?

• Y enters the cell through the same carrier
• Y stays outside without crossing the membrane
• Y leaves the cell through the same carrier

Blocking the sodium potassium pump must stop sodium-dependent glucose entry immediately, even if a driving sodium gradient remains.

A student calls sodium-dependent glucose entry primary active transport because it depends on ATP. Which correction explains why it is secondary?

• It moves glucose without any energy input, so the uptake is passive diffusion
• It moves glucose through the sodium potassium pump, which splits ATP directly
• It uses energy from an ion gradient maintained by the ATP-driven pump