Question

What type of transport uses a pre-existing gradient to drive the transport of another molecule?

A) Active transport
B) Passive transport
C) Secondary active transport
D) Facilitated diffusion

Answer 1

Secondary active transport is the transport mechanism that uses a pre-existing gradient, established by primary active transport, to move another molecule across the cell membrane.

Step-by-step explanation:

The type of transport that uses a pre-existing gradient to drive the transport of another molecule is known as secondary active transport. This mode of transport leverages the electrochemical gradient established by primary active transport to fuel the movement of substances across a cell membrane, such as amino acids and glucose. While it does not directly use ATP, it still requires the energy that was stored during primary active transport, making it an active process.