Membrane Structure and Function

These flashcards cover key concepts related to membrane structure and function, transport processes, and body fluid compartments, as outlined in the lecture.

What is the primary function of the plasma membrane?

It separates the living cell from its non-living surroundings.

What are the two main types of transport processes across biological membranes?

Active and passive transport.

What does selective permeability mean regarding the plasma membrane?

The plasma membrane allows some substances to cross it more easily than others.

According to the fluid mosaic model, what are cellular membranes composed of?

Fluid mosaics of lipids and proteins.

What are the two types of phospholipids?

Phosphoglycerides and phosphosphingolipids.

What role do glycolipids play in the membrane?

They are involved in cell recognition and signaling.

What effect does cholesterol have on membrane fluidity at warm temperatures?

Cholesterol restrains the movement of phospholipids, reducing fluidity.

What are the main functions of membrane proteins?

Transport, enzymatic activity, signal transduction, intercellular joining, cell-cell recognition, and attachment to the cytoskeleton and ECM.

What is the difference between diffusion and osmosis?

Diffusion is the movement of solutes; osmosis is the movement of water across a semipermeable membrane.

Describe isotonic, hypertonic, and hypotonic solutions in relation to cells.

Isotonic: no net water movement; Hypertonic: cell loses water; Hypotonic: cell gains water.

What is active transport?

Transport of substances against their concentration gradient requiring energy.

What is the sodium-potassium pump?

An active transport system that moves 3 Na+ out and 2 K+ in, contributing to membrane potential.

What is cotransport?

Coupled transport of substances by a membrane protein, driven by the concentration gradient of another substance.

What are the three types of endocytosis?

Pinocytosis, phagocytosis, and receptor-mediated endocytosis.

What is the glycocalyx?

A carbohydrate cover on the external side of the cell membrane facilitating cell-cell recognition.

What is osmoregulation?

The control of water balance in cells, especially in cells without walls.

Define tonicity.

The ability of a solution to cause a cell to gain or lose water.

What is the significance of the fluid mosaic model?

It describes the structural and functional properties of biological membranes, emphasizing their dynamic nature.