Question

Which of the following is a characteristic of active transport?

1) Saturable uptake rate
2) Use of ATP or a proton gradient as a source of metabolic energy
3) Can move materials against a concentration gradient
4) All of the choices are correct.

Answer 1

Active transport includes a saturable uptake rate, use of ATP or a proton gradient for energy, and movement of substances against concentration gradients; hence, all choices are correct.

Step-by-step explanation:

Active transport is a cellular process that moves substances against their concentration gradient. The characteristics of active transport include a saturable uptake rate, the use of ATP or a proton gradient as a source of metabolic energy, and the ability to move materials against a concentration gradient. Therefore, all of the choices given in the question are correct. Active transport mechanisms, such as the sodium-potassium pump, utilize ATP to fuel the transport, moving ions like sodium and potassium in opposite directions to maintain the necessary concentration gradients critical for cellular functions.