Cells - Transport Across Cell Membranes: Key Terms

Question 1

Plasma membrane

Answer 1

All membranes that are around and within all cells.

Question 2

Phospholipids

Answer 2

Important components of cell-surface membranes.

Question 3

Protein channels

Answer 3

Trans membrane proteins that allow the passage of specific larger substances across the membrane

Question 4

Carrier proteins

Answer 4

They bind to ions or molecules, then change shape in order to move these molecules across the membrane.

Question 5

Fluid mosaic model

Answer 5

The way to describe the way in which all the various molecules are combined into the cell surface membrane, and that the interrelationship between the phospholipids and proteins can be altered and changes.

Question 6

Diffusion

Answer 6

The net movement of the molecules or ions from a region where they are more highly concentrated to one where their concentration is lower until evenly distributed.

Question 7

Facilitated diffusion

Answer 7

The passive process by which charged ions and polar molecules diffuse across the cell-surface membrane through protein channels and carrier proteins.

Question 8

Osmosis

Answer 8

The passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a selectively permeable membrane.

Question 9

Active transport

Answer 9

The movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using ATP and carrier proteins.

Question 10

Co-transport

Answer 10

The individual movement of molecules using a concentration gradient which has already been set up by active transport.

Question 11

Sodium potassium pump

Answer 11

Where sodium ions are actively removed from the cell/organelle and ions are actively taken in from the surroundings.