Cell Transport

Millers H Bio

Passive transport

The movement of molecules across a cell membrane without the use of energy, relying on concentration gradients.

Active transport

The movement of molecules across a cell membrane against their concentration gradient, requiring energy in the form of ATP.

Facilitated diffusion

A type of passive transport that utilizes transport proteins to move molecules across the cell membrane down their concentration gradient.

Diffusion

The process by which molecules spread from areas of high concentration to areas of low concentration without the need for energy.

When is facilitated diffusion needed?

Facilitated diffusion is needed when molecules are too large or polar to pass directly through the lipid bilayer of the cell membrane, requiring specific transport proteins to aid their movement.

Channel proteins

A type of transport protein that form pores in the cell membrane, allowing the selective passage of ions and small molecules.

Gated channel proteins

A type of channel protein that can open or close in response to specific signals, regulating the flow of ions or molecules across the cell membrane.

Carrier proteins

A type of transport protein that binds to specific substances and changes shape to shuttle them across the cell membrane.

Osmosis

The process by which water molecules move across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Hypotonic solutions

A type of solution where the solute concentration is lower than that of the cell's cytoplasm, causing water to flow into the cell.

Cytolysis

Cell bursting

Hypertonic solutions

A type of solution where the solute concentration is higher than that of the cell's cytoplasm, causing water to flow out of the cell.

Plasmolysis

Cell shriveling

Isotonic solutions

A type of solution where the solute concentration is equal to that of the cell's cytoplasm, causing water to have no net movement.

Endocytosis

The taking in of materials via the cell membrane.

Phagocytosis

The taking in of solid particles.

Pinocytosis

The taking in of liquids.

Receptor-mediated

Receptor proteins on the cell surface that are used to capture a specific target molecule.

Exocytosis

Process by which cells expel substances.

Protein pump

A protein pump moves molecules or ions across a cell membrane against their concentration gradient, a process called active transport that requires energy, typically from ATP.

What uses receptor proteins?

Hormones, enzymes, toxins, and viruses use receptor proteins.

What does the most common protein pump do?

The sodium-potassium pump uses energy to move sodium ions out of a cell and potassium ions into the cell, which is vital for maintaining membrane potential, especially in neurons.