Differences Between Active and Passive Membrane Transport Mechanisms

Distinguish between active and passive transport, and indicate which type of membrane transport protein carries out each.

Passive: no energy used; channel or transporterActive: energy of ATP to move against the concentration gradient

Active transport and passive transport are two types of membrane transport mechanisms used by cells to move substances across the cell membrane.

Active transport refers to the movement of substances against their concentration gradient, which requires the expenditure of energy in the form of ATP. Active transport is carried out by membrane transport proteins called pumps, which use energy to move molecules or ions from areas of lower concentration to areas of higher concentration.

Passive transport, on the other hand, refers to the movement of substances along their concentration gradient, which does not require energy input from the cell. Passive transport moves substances from areas of higher concentration to areas of lower concentration. Passive transport is carried out by membrane transport proteins called channels and carriers.

Channels are membrane proteins that form pores or channels in the cell membrane through which specific molecules can pass. Channels are usually selective, allowing only certain molecules through. Examples of channels include ion channel proteins that facilitate the movement of ions across the membrane.

Carriers are membrane proteins that bind to specific molecules on one side of the membrane and undergo a conformational change to transport the molecule across the membrane to the other side. Carriers are used to transport molecules that are too large, too charged, or too polar to pass through channels. Examples of carriers include glucose transporters that facilitate the movement of glucose across the cell membrane.

In summary, active transport is carried out by pumps, while passive transport is carried out by channels and carriers.

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