Facilitated Diffusion and Tonicity

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What is facilitated diffusion?

A passive transport process that allows molecules to cross membranes via specific transport proteins.

Which molecules typically require facilitated diffusion?

Charged ions and large polar molecules.

What role do channel proteins play in facilitated diffusion?

They enable the movement of specific ions across the plasma membrane.

What’s the difference between active transport and facilitated diffusion?

Active transport requires energy, while facilitated diffusion does not.

Define osmosis.

The diffusion of water across a selectively permeable membrane.

What is a hypotonic solution?

A solution with a lower solute concentration compared to the inside of the cell.

What happens to a cell a hypertonic solution?

The cell will lose water and may shrivel.

What is the function of aquaporins?

To facilitate the rapid transport of water across cell membranes.

Explain the concept of water potential.

It is the potential energy of water in a system compared to pure water, influencing the direction of water movement.

What is the ionization constant (i) in the solute potential formula?

It represents the number of particles the solute dissaociates into in solution.

How does facilitated diffusion affect membrane potentials?

It can cause the membrane to become polarized by moving charged ions.

What is a hypertonic solution?

A solution with a higher solute concentration compared to the inside of the cell.

What is Tonicity?

The ability of a surrounding solution to affect the cell’s shape of tone by altering its internal water volume.

What is the significance of concentration gradients in molecular movement?

Molecules move from areas of high concentration to areas of low concentration to reach equilibrium.

How does osmoregulation impact cellular function?

It regulates internal solute concentration and water balance, crucial for cell health.

What will happen to a cell in an isotonic solution?

There will be no net movement of water, and the cell will retain its shape.

Solute Potential

A measure of the tendency of water to move into a solution due to solute concentration.

How is facilitated diffusion a specific process?

It occurs through specific membrane proteins that only allow certain molecules to pass.

What is the role of sodium-potassium pumps?

They actively transport Na+ out of and K+ into the cell against their concentration gradients.

What is dynamic homeostasis?

The process by which biological systems maintain stable internal conditions despite changes in external environments.