Cell Membrane and Transport Mechanisms

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What is the Fluid-Mosaic Model?

Back

A model describing the structure of cell membranes, where the membrane is a fluid combination of phospholipids, cholesterol, and proteins. The 'mosaic' aspect refers to the pattern produced by the scattered protein molecules when the membrane is viewed from above.

Front

Define Osmosis.

Back

The movement of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration, aiming to equalize the solute concentrations on both sides of the membrane.

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What is Simple Diffusion?

Back

The passive movement of molecules from an area of higher concentration to an area of lower concentration, without the need for energy or assistance from membrane proteins.

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Explain Facilitated Transport.

Back

The process of spontaneous passive transport of molecules or ions across a biological membrane via specific transmembrane integral proteins.

Front

What are Embedded Proteins?

Back

Proteins that are permanently attached to the cell membrane and play various roles, including transport, signal transduction, and acting as enzymes.

Front

Describe the Phospholipid Bilayer.

Back

A double layer of phospholipids that makes up the cell membrane, with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward, creating a barrier that separates the cell from its environment.

Front

What is a Gated Channel Protein?

Back

A type of protein in the cell membrane that opens or closes in response to a specific stimulus, allowing ions or molecules to pass through the membrane when open.

Front

Define Protein Pump.

Back

A type of membrane protein that uses energy, usually from ATP, to move molecules or ions across the cell membrane against their concentration gradient.

Front

What is Active Transport?

Back

The movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration, using energy (usually from ATP). This process requires the assistance of membrane proteins, such as protein pumps, to move substances against their concentration gradient.

Front

Explain Passive Transport.

Back

The movement of molecules or ions across a cell membrane from a region of higher concentration to a region of lower concentration, without the use of energy. This process relies on the natural kinetic energy of the molecules and includes methods such as simple diffusion, facilitated diffusion, and osmosis.