Biological Membranes Study Guide

These flashcards cover key terms and concepts related to biological membranes, their functions, transport mechanisms, and structural components.

Phospholipid

A molecule that is a major component of cell membranes, consisting of a polar hydrophilic head and two non-polar hydrophobic tails.

Glycoprotein

A protein that has carbohydrate groups attached to the polypeptide chain.

Selective Permeability

The property of biological membranes that allows some substances to pass through while restricting others.

Fluid Mosaic Model

A model that describes the structure of cell membranes as a mosaic of various components, including phospholipids, cholesterol, and proteins that move fluidly within the layers.

Osmosis

The diffusion of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration.

Hypertonic Solution

A solution with a higher solute concentration compared to the inside of a cell, leading to cell shrinkage.

Hypotonic Solution

A solution with a lower solute concentration compared to the inside of a cell, causing the cell to swell and possibly burst.

Isotonic Solution

A solution with equal solute concentration inside and outside of a cell, resulting in no net movement of water.

Facilitated Diffusion

A type of passive transport that uses membrane-spanning transport proteins to move molecules across a cell membrane from high to low concentration.

Carrier Proteins

Proteins that transport specific molecules across a cellular membrane by binding to them and changing shape.

Cholesterol

A steroid molecule that intersperses within the phospholipid bilayer, helping to regulate membrane fluidity and stability.

Integral Protein

Proteins that span the membrane and are involved in transport and communication functions.

Peripheral Protein

Proteins that are associated with the membrane but do not span it; they typically serve as enzyme functions or signaling molecules.

Compartmentalization

The process by which cellular structures isolate specific biochemical environments or functions within an organism.

Micelles

Spherical structures formed by phospholipids in water, with the hydrophobic tails tucked inside and the hydrophilic heads facing outward.

Membrane Fluidity

The ability of the lipid molecules within a membrane to move and shift, affecting the membrane's flexibility and selectivity.