Which of the following is a way in which primary and secondary active transport may work together?

• A. Primary active transport can be used to create a concentration gradient of sodium such that sodium and glucose can move into the cell together via antiport mechanism.
• B. Primary active transport is used to create ATP necessary to drive secondary active transport.
• C. Primary active transport can be used to create a concentration gradient of sodium such that sodium and glucose can move into the cell together via secondary active symport.
• D. Primary and secondary active transport always oppose each other so they never work together.

Answer: (C)

Verified step by step guidance

1. Understand the definitions: Primary active transport involves the direct use of ATP to transport molecules across a membrane, while secondary active transport uses the energy from the electrochemical gradient created by primary active transport.
2. Identify the role of primary active transport: It often involves the use of ATP to pump ions like sodium (Na+) out of the cell, creating a concentration gradient.
3. Recognize the role of secondary active transport: It utilizes the energy stored in the concentration gradient created by primary active transport to move other substances against their own gradients.
4. Consider the symport mechanism: In secondary active transport, a symport mechanism allows two substances to move in the same direction across the membrane. For example, sodium and glucose can enter the cell together.
5. Connect the concepts: Primary active transport creates a sodium gradient, which secondary active transport (via symport) uses to bring glucose into the cell along with sodium, demonstrating how they work together.