Active Transport

Active Transport

Definition

  • Active transport is the process in which substances move against electrochemical or concentration gradients.

Characteristics (MSSCE)

  1. Movement: Chemicals are moved against gradients.

  2. Saturability: Transport is saturable at high substrate concentrations.

  3. Selectivity: Certain structural features lead to selectivity.

  4. Competitive Inhibition: Inhibited by similar chemicals that are also carried by the transporter.

  5. Energy Requirement: Expenditure of energy is necessary; metabolic inhibitors can block this process.

Mechanism

  • Substances form a complex with a membrane-bound carrier on one side of the membrane, then translocate to the other side where they are released.

    • The carrier returns to repeat the cycle.