Cell Membrane Structure and Function Flashcards

Vocabulary flashcards based on Lecture 15 notes, focusing on the structure and function of the cell membrane.

Cell Membrane

The lipid bilayer of the cell membrane is composed of lipids in which proteins are embedded.

Fluid Mosaic Model

A model that describes the cell membrane as a 'sea of lipids where proteins float like icebergs'.

Selective Permeability

The property of the membrane that allows some substances to pass through while restricting others.

Amphipathic Lipids

Lipids with both polar (hydrophilic) and nonpolar (hydrophobic) regions.

Integral Proteins

Proteins that extend into or completely across the cell membrane.

Peripheral Proteins

Proteins attached to the inner or outer surface of the cell membrane.

Receptor Protein

A type of membrane protein that binds to specific molecules, triggering a cellular response.

Cell Identity Markers

Membrane proteins that identify a cell as part of the same organism, preventing immune system attack.

Linker Proteins

Membrane proteins that join cells together or link cells to the extracellular matrix.

Enzymes (Membrane)

Proteins that catalyze biochemical reactions at the cell membrane.

Ion Channels

Proteins that form pores or channels allowing specific ions to cross the membrane.

Transporter Proteins

Proteins that facilitate the movement of specific molecules across the cell membrane.

Diffusion

The movement of particles from an area of high concentration to an area of low concentration.

Concentration Gradient

The difference in concentration of a substance between two areas.

Electrical Gradient

The difference in electrical potential across a cell membrane.

Electrochemical Gradient

The combined influence of electrical and concentration gradients on ion movement.

Membrane Potential

The ability of a membrane to maintain a difference in charged ions between the inside and outside.

Osmosis

The net movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration.

Pd (Diffusional Permeability)

The component of water movement through the lipid bilayer; small, mercury insensitive, and temperature dependent.

Pf (Filtration Permeability)

The component of water movement through water channels; large, mercury sensitive, and temperature independent.

Aquaporins

Membrane protein channels specifically designed for water transport.

Osmolarity

The concentration of a solution expressed as the total number of solute particles per liter.

Osmotic Pressure

The pressure applied to a solution to prevent the inward flow of water across a semi-permeable membrane.

Phospholipids

Lipids composed of a glycerol molecule, two fatty acids, and a phosphate group.

Cholesterol

A lipid molecule with a polar head and a nonpolar tail that is a key component of cell membranes and affects membrane fluidity.