Solutes

Definition

Solutes are substances that are dissolved in a solvent, forming a solution. In biological systems, solutes can include ions, small molecules, and larger macromolecules.

5 Must Know Facts For Your Next Test

1. Solutes move across plasma membranes through passive transport mechanisms like diffusion and facilitated diffusion.
2. The concentration gradient of solutes is a driving force for passive transport.
3. Small nonpolar solutes can diffuse directly through the lipid bilayer of the plasma membrane.
4. Polar or charged solutes require specific transport proteins to facilitate their movement across the membrane.
5. Osmosis is a type of passive transport that specifically involves the movement of water in response to solute concentrations.

Review Questions

• How do solutes typically move across the plasma membrane?
• What role does the concentration gradient play in the movement of solutes?
• Why do polar or charged solutes need transport proteins to cross the plasma membrane?

Related terms

Passive Transport:

The movement of substances across cell membranes without energy input from the cell.

Diffusion:

The process by which molecules spread from areas of high concentration to areas of low concentration.

Facilitated Diffusion: A type of passive transport where molecules move across membranes with the help of transport proteins.