Membrane Structure and Transport

What is the fluid mosaic model of the cell membrane?

The membrane is a fluid structure made of a phospholipid bilayer with embedded proteins, carbohydrates, and cholesterol, allowing flexibility and selective transport.

What are the main components of the cell membrane?

Phospholipids, proteins, carbohydrates, and cholesterol.

What is the function of phospholipids in the cell membrane?

Form the bilayer; create a barrier that separates the inside from the outside of the cell.

What is the function of proteins in the cell membrane?

Transport molecules, act as receptors, provide structural support, and catalyze reactions.

What is the function of carbohydrates in the cell membrane?

Cell recognition, signaling, and adhesion.

What is the function of cholesterol in the cell membrane?

Stabilizes membrane fluidity and structure.

What is diffusion?

Movement of molecules from a region of high concentration to a region of low concentration until equilibrium is reached.

What is facilitated diffusion?

Diffusion of molecules through a membrane with the help of transport proteins; no energy required.

What is osmosis?

Movement of water molecules across a partially permeable membrane from high water potential to low water potential.

What is active transport?

Movement of molecules against the concentration gradient using energy (ATP) and carrier proteins.

What is endocytosis?

Process by which cells take in large particles or liquids by engulfing them in a vesicle.

What is exocytosis?

Process by which cells release large molecules or waste products by vesicles fusing with the cell membrane.

What factors affect diffusion and osmosis?

Concentration gradient, surface area, temperature, size of molecules, and distance over which diffusion occurs.