Cell Transport + Diffusion

Selective permeability

Allowing CERTAIN things in and out of the cell; the cell membrane is selective.

What in the lipid bilayer determines what goes in and out?

Proteins

What is passive transport?

When molecules move across the cell membrane with no energy required, going from high concentration to low concentration.

When does passive transport occur?

Diffusion and osmosis

What type of proteins allow BIGGER molecules to pass through the membrane?

Channel Proteins and Carrier Proteins

What is it called when a protein determines if a molecule is able to pass through the membrane or not?

Facilitated Diffusion

True or False: A protein is not always required for passive transport

True

What is active transport?

When molecules are moving through the cell membrane AGAINST the concentration gradient.

What special type of vacuoles do protists have?

Contractile vacuole

Types of Active Transport

Endocytosis and Exocytosis

Endocytosis

When the cell membrane engulfs/eats the particles and create a vacuole.

Exocytosis

When cells release waste materials in vacuoles through the cell membrane using active transport

Diffusion

The movement of molecules from HIGH or LOW concentration, only lets small molecules pass through, trying to reach equilibrium.

Dynamic Equilibrium

Each “side” is trying to reach equilibrium but never do because the molecules are constantly moving.

What state of matter can move through cell membranes?

Only works well with waters, gases, molecules that don’t have a + or - charge, and some hormones.

Concentration Gradient

Solutes (particles) are moving through a solute or gas from HIGH to LOW concentration. Areas are usually separate by a membrane.

Osmosis

Diffusion by water. Doesn’t require energy, goes from high to low. All water (except for distilled) have natural solutes.

In a water solution, which way do the solutes move?

Low solute concentration to high solute concentration

Hypotonic Solution

Where solute concentration is lower on the outside and higher inside. Hypo = less. Goes from low to high. The cell can break (cytolysis).

Hypertonic Solution

Solute concentration is higher outside, lower inside. Water leaves the cell. The cell shrinks (plasmolysis).

Isotonic Solution

The inside concentration of solutes = the outside concentration of solutes

Turgor Pressure

When water enters the cell and is pressurized.

What is it called when turgor pressure increases?

Cytolysis

What is it called when turgor pressure decreases?

Plasmolysis