Biol 107: Osmosis and Membrane Transport

These flashcards cover key concepts related to osmosis, membrane transport, and various types of protein transport mechanisms based on the notes from Biol 107.

What is osmosis?

The movement of water across a semipermeable membrane to equalize solute concentration on both sides.

What happens to free energy in relation to solute concentration?

The higher the solute concentration, the lower the free energy of the system.

Which substances can diffuse through the phospholipid bilayer freely?

Small, non-polar substances like O₂ and CO₂ can diffuse through the phospholipid bilayer.

How does water move across the cell membrane?

Water can diffuse through the membrane, but not very efficiently.

What do channel proteins do?

Channel proteins provide facilitated diffusion of ions and water without requiring energy.

How can particles with charge (polar) pass through membranes?

They can go through ion channels which may be regulated through gating.

What is the function of the sodium-potassium pump?

It exports 3 Na+ ions while importing 2 K+ ions, moving ions in opposite directions against their concentration gradients.

What is an example of a symporter?

The Na-Glucose transporter-1 in intestinal cells uses the favorable chemical gradient of one molecule to move another in the same direction.

What are primary antiporters?

Proteins that move ions in opposite directions against both concentration gradients, such as the sodium-potassium pump.

What is facilitated diffusion?

The process by which ions and water move across the membrane through channel proteins without the use of energy.