Diffusion and Osmosis

These flashcards cover key concepts about diffusion, osmosis, cell membranes, and tonicity critical for understanding the material in Unit 4.

What is diffusion?

Movement of a solute across a surface.

What is osmosis?

Movement of water across a surface.

What does semi-permeability of a cell membrane mean?

Some materials can pass through while others cannot, creating a concentration gradient.

What is a concentration gradient?

When the contents on one side of a barrier are more concentrated than on the other.

What are molecules in relation to cell membranes?

The organelles and other things that move across the membrane into and out of the cells.

How can the structure or size of a molecule affect its movement across a membrane?

It can limit its ability to move across a membrane.

What causes diffusion to be a passive process?

Random collisions that cause solute particles to move from an area of high concentration to an area of low concentration.

What can alter the rate of diffusion?

The environment, including temperature and interactions with other molecules.

Define hypertonic solution.

A solution with more solute particles when compared to another solution.

Define isotonic solution.

A solution with the same number of solute particles when compared to another solution.

Define hypotonic solution.

A solution with fewer solute particles when compared to another solution.

What does high water potential indicate?

It indicates that it is easier for water to move and cross barriers.

What does low water potential indicate?

It indicates that it is harder for water to move and cross barriers.

What happens to red blood cells in a hypertonic solution?

Cytoplasm shrinks from the cell wall.

What happens to red blood cells in a hypotonic solution?

Cells swell and may burst.

Why is tonicity important for cells?

It is critical for the proper functioning and maintenance of cell structure.

What is concentration Gradient

Difference in concentration between two solutions

Diffusion

Movement of solute particles from an area of high concentration to an area low concretion

Solute

Everything but water

Diffusion is…

Passive

Brownian movement

random movement of particles in solution due to molecular collisionsthat causes particles to move in a zigzag pattern.

Increase in Temperature

increases rate of diffusion