Question

question ① which of the following is correct regarding the movement of substances against their concentration gradient? select all that apply active transport facilitated diffusion requires energy does not depend on a gradient

Explanation:

1. Active transport: Active transport is the process by which substances are moved against their concentration gradient (from low to high concentration). So this is correct.
2. Facilitated diffusion: Facilitated diffusion is a type of passive transport where substances move down their concentration gradient (from high to low) with the help of transport proteins. So this is incorrect.
3. Requires energy: Moving substances against their concentration gradient is an energy - consuming process. Active transport uses energy (usually ATP) to move substances against the gradient. So this is correct.
4. Does not depend on a gradient: The movement against the concentration gradient is defined by moving from an area of low concentration to high concentration, so it is related to the concentration gradient (it is moving against it). However, the statement "Does not depend on a gradient" can be interpreted in the sense that the movement is not driven by the gradient (unlike passive transport which is driven by the gradient). Since active transport is against the gradient and is not driven by the gradient (it needs energy to go against it), this can be considered correct in the context of the energy - dependent nature of moving against the gradient (as it is not relying on the gradient to drive the movement, but rather energy).

Answer:

• Active transport
• Requires energy
• Does not depend on a gradient