Explain the fundamental difference between symport and antiport mechanisms in secondary active transport. Focus on the direction of solute movement.

Symport involves the movement of two or more different solutes across the membrane in the same direction, whereas antiport involves the movement of two or more different solutes in opposite directions.

In secondary active transport, what is the primary driving force that enables another solute to move against its concentration gradient?

The movement of an ion down its electrochemical gradient

Imagine a cell where sodium ions are at a higher concentration outside the cell than inside. A new molecule, substance 'Z', is transported into the cell along with sodium. Substance 'Z' is found to have a higher concentration inside the cell than outside. Based on this information, is the transport of substance 'Z' an example of symport or antiport? Explain your reasoning.

This is an example of symport. Since sodium is moving from high to low concentration (outside to inside) and substance 'Z' is also moving into the cell, they are moving in the same direction, which defines symport.

Symport versus Antiport

12th GradeScience30 min

Learning Objective

I can compare and contrast symport and antiport mechanisms in cellular co-transport.

Lesson Flow

Watch Video

8 min

Human Physiology - Secondary Active Transport

Janux

Guided Notes

6 min

Key concepts students will learn:

•
In secondary active transport, one ion moves down its concentration gradient, causing another ion or molecule to move against its gradient.
•
Symport (or co-transport) means that both solutes move in the same direction, while antiport (or counter-transport) means the solutes move in opposite directions.
•
In the sodium-glucose co-transport example, sodium moves from a high to low concentration, creating the energy to drive glucose from a low to high concentration.

Practice

10 min

3 questions • Multiple choice & Short answer

Exit Ticket

5 min

“Describe the key difference in the direction of movement of molecules between symport and antiport mechanisms in cellular co-transport. Provide an example of each.”

Teacher Guide

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Symport versus Antiport

Learning Objective

Lesson Flow

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Guided Notes

Practice

Exit Ticket

Teacher Guide

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