Plasma Membranes and Membrane Permeability

These flashcards cover key terminology and concepts related to plasma membranes, their structure, and functions.

Plasma membrane

A cell membrane that separates the internal environment of the cell from the external environment.

Phospholipid

A molecule that forms the bilayer of the plasma membrane, consisting of a hydrophilic head and hydrophobic tails.

Amphipathic

Referring to molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts.

Selective permeability

The ability of membranes to regulate which substances can enter or exit the cell.

Fluid Mosaic Model

A model that describes the structure of cell membranes as a mosaic of various proteins that float in or on the fluid lipid bilayer.

Integral proteins

Proteins that are embedded in the lipid bilayer and can span the entire membrane.

Peripheral proteins

Proteins that are not embedded in the lipid bilayer but are loosely attached to the surface.

Glycoproteins

Carbohydrates that are covalently bonded to proteins and are important for cell-to-cell recognition.

Glycolipids

Carbohydrates that are covalently bonded to lipids and help with cell recognition.

Cholesterol

A lipid that helps maintain membrane fluidity at both high and low temperatures.

Hydrophilic heads

The water-attracting part of a phospholipid that faces outward toward the aqueous environments.

Hydrophobic tails

The water-repelling part of a phospholipid that faces inward, away from the aqueous environments.

Plasmodesmata

Channels through the cell wall that connect adjacent plant cells and allow for communication and transport of materials.

Cell wall

An extracellular structure found in plant cells that provides shape, structure, and protection.

Saturated fatty acid

A type of fatty acid with no double bonds between carbon atoms, leading to a straight chain that can pack tightly.

Unsaturated fatty acid

A type of fatty acid with one or more double bonds between carbon atoms, creating kinks that prevent tight packing.