Cell Membrane and Transport Mechanisms

These flashcards cover key concepts related to the structure and function of cell membranes, including transport mechanisms.

What is the primary function of the cell membrane?

The cell membrane acts as a barrier, regulates what goes in and out of the cell, and facilitates communication and attachment between cells and mediates processes like cell crawling

What are the main components of cell membranes?

Cell membranes are primarily composed of phospholipids, cholesterol (sterols), and proteins including glycoproteins and glycolipids.

Describe the structure of a phospholipid.

A phospholipid consists of a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) fatty acid tails, which can be saturated or unsaturated.

What influences the fluidity of cell membranes?

Fluidity is influenced by temperature, the saturation of fatty acid, cholesterol and fatty acid tail length

What are the two types of membrane proteins?

Integral proteins, which are tightly embedded in the membrane, and peripheral proteins, which are loosely associated with the membrane.

What is facilitated transport?

Facilitated transport is the process where substances move from high concentration to low concentration across a membrane through specific transport proteins.

What is active transport and how does it work?

Active transport is the movement of substances from low concentration to high concentration using energy, typically through ATP-powered pumps.

Give an example of a substance that easily crosses cell membranes.

Oxygen (O2), carbon dioxide (CO2), and water (H2O) can readily cross cell membranes through simple diffusion.

What is the sodium-potassium pump?

The sodium-potassium pump is an ATP-powered pump that moves 3 sodium ions out of the cell and 2 potassium ions into the cell to maintain concentration gradients.

What role do transport proteins play in the cell membrane?

Transport proteins facilitate the movement of substances across the membrane, either passively or actively.