the fluid mosaic model

What is the fluid mosaic model?

A theory that describes the structure of cell membranes as a mosaic of various proteins that float in or on the fluid lipid bilayer.

Who proposed the fluid mosaic model?

The fluid mosaic model was proposed by S.J. Singer and Garth L. Nicolson in 1972.

What are the main components of the cell membrane according to the fluid mosaic model?

Phospholipids, proteins, cholesterol, and carbohydrates.

What is the role of phospholipids in the fluid mosaic model?

Phospholipids form the bilayer that acts as a barrier to most water-soluble substances.

How do proteins function in the fluid mosaic model?

Proteins serve various functions such as transport, acting as enzymes, or signaling.

What is the significance of 'fluid' in the fluid mosaic model?

It indicates that the lipids and proteins can move laterally within the layer, allowing flexibility and movement.

What is the role of cholesterol in the fluid mosaic model?

Cholesterol stabilizes the membrane's fluidity, making it less permeable to very small water-soluble molecules.

What are integral proteins?

Proteins that are embedded in the lipid bilayer and span the entire membrane.

What are peripheral proteins?

Proteins that are attached to the exterior or interior surfaces of the membrane but do not penetrate the hydrophobic core.

What is the function of glycoproteins in the fluid mosaic model?

Glycoproteins are involved in cell recognition and signaling due to carbohydrate chains attached to them.

What is the function of glycolipids?

Glycolipids are involved in cell signaling and recognition, helping cells communicate.

How do substances move across the membrane in the fluid mosaic model?

Substances can move by passive transport, active transport, or facilitated diffusion.

What is passive transport?

The movement of substances across the membrane without the use of energy, usually down a concentration gradient.

What is active transport?

The movement of substances against their concentration gradient, requiring energy (ATP).

What is facilitated diffusion?

A process where substances pass through a membrane with the help of transport proteins, without energy input.

What is a concentration gradient?

A difference in the concentration of a substance across a space or membrane.

What is selective permeability?

The property of a membrane that allows only certain molecules to pass through while blocking others.

What is membrane fluidity?

The viscosity of the lipid bilayer of a cell membrane, affecting its permeability and the movement of proteins.

What factors affect membrane fluidity?

Temperature, lipid composition, and the presence of cholesterol.

What is the role of signaling molecules in the fluid mosaic model?

Signaling molecules can bind to receptors on the membrane to trigger cellular responses.

How do cells communicate using the fluid mosaic model?

Cells communicate using receptors, signaling molecules, and interactions between glycoproteins and glycolipids.

What is an example of a membrane protein?

Receptor proteins, channel proteins, and carrier proteins are examples of membrane proteins.

What is a transmembrane protein?

A type of integral protein that spans the entire membrane and helps transport molecules across it.

What are lipid rafts?

Microdomains in the membrane that have a distinct composition and play a role in cell signaling.

What is membrane asymmetry?

The different compositions of the inner and outer leaflets of the lipid bilayer.

Why is the fluid mosaic model important?

It explains the dynamic structure of the cell membrane and how it facilitates various cellular functions.

How can the fluid mosaic model be observed?

It can be studied using techniques such as freeze-fracture microscopy and fluorescence recovery after photobleaching (FRAP).