Solutes are transported in tissues through different mechanisms, including passive diffusion, facilitated diffusion, active transport, and endocytosis.
Passive Diffusion
Passive diffusion is the movement of solutes from an area of higher concentration to an area of lower concentration without the need for energy. Small, nonpolar molecules such as oxygen and carbon dioxide typically move by this method.
Facilitated Diffusion
Facilitated diffusion involves transport proteins that help move solutes across the cell membrane. This process does not require energy and is crucial for the transport of glucose and amino acids.
Active Transport
Active transport requires energy in the form of ATP to move solutes against their concentration gradient. The sodium-potassium pump is an example, maintaining the electrochemical gradients essential for cellular function.
Endocytosis
Endocytosis is a process where cells engulf solutes or particles, forming vesicles. This method is vital for large molecules that cannot pass through the cell membrane by diffusion or active transport.
