Carrier-Mediated Transport

Characteristics of carrier-mediated transport

1. Specificity - Each carrier protein will bind and transport only specific substances. 2. Saturation limits 3. Regulation - The binding of other molecules can affect the activity of carrier proteins. (Ex) Hormones provide an important means of coordinating carrier protein activity throughout the body.

Active transport

A high energy bond (in ATP or another high energy compound) provides the energy needed to move ions or molecules across the membrane.

Facilitated diffusion

Substances that are essential nutrients, such as glucose and amino acids, are insoluble in lipids and too large to fit through membrane channels. They can be transported across the membrane by carrier proteins in this process.

Secondary active transport

This transport mechanism moves with a specific substrate down its concentration gradient, and can also move another substrate at the same time, regardless of its concentration gradient.

Carrier-mediated transport

When integral proteins bind specific ions or organic substrates and carry them across the plasma membrane.