Membranes and Membrane Transport

These flashcards cover essential concepts related to membranes and membrane transport, focusing on structure, function, and mechanisms of transport across biological membranes.

What are phospholipids composed of?

Phospholipids consist of a hydrophilic phosphate head and a hydrophobic hydrocarbon tail.

What is the fluid mosaic model?

The fluid mosaic model describes the structure of biological membranes, emphasizing their dynamic and flexible nature, consisting of phospholipids, proteins, cholesterol, and carbohydrates.

What role do glycoproteins play in cell adhesion?

Glycoproteins facilitate interactions between cells, promoting tissue integrity.

What is facilitated diffusion?

Facilitated diffusion is the passive movement of particles through protein channels or carriers that is selective and depends on specific transport proteins.

How does osmosis occur?

Osmosis is the passive movement of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.

What is the primary function of pump proteins?

Pump proteins are integral membrane proteins that drive active transport, moving particles against their concentration gradient using energy from ATP.

How does the presence of cholesterol affect membrane fluidity?

Cholesterol helps maintain membrane fluidity by preventing phospholipids from packing too closely together or separating too far apart.

What are the two types of membrane proteins?

Integral proteins, which are embedded in the lipid bilayer, and peripheral proteins, which are attached to one surface of the membrane.

What is selective permeability?

Selective permeability refers to the property of biological membranes that allows certain substances to pass while preventing others, essential for maintaining cellular homeostasis.

Describe the structure and function of aquaporins.

Aquaporins are specialized proteins that facilitate the efficient transport of water across cell membranes.

What happens during endocytosis?

Endocytosis is the process where external substances are taken into the cell by the inward pouching of the plasma membrane, forming a vesicle.

What is the role of sodium-potassium pumps in cellular function?

Sodium-potassium pumps exchange 3 sodium ions out of the cell for 2 potassium ions into the cell, maintaining the electrochemical gradient essential for cellular function.