Cellular and Molecular Biology: Plasma Membrane

This set of flashcards covers key vocabulary related to the structure and function of the plasma membrane from the lecture on Cellular and Molecular Biology.

Plasma Membrane

A thin, fragile structure that separates cells from the external environment; approximately 5 to 10 nm wide.

Selectively Permeable Barrier

A property of membranes that prevents the unrestricted exchange of molecules.

Lipid Bilayer

A double-layered arrangement of phospholipids that forms the core of cell membranes.

Integral Proteins

Proteins that span the entire membrane and interact with both the extracellular and cytoplasmic environments.

Peripheral Proteins

Proteins located on the surface of the membrane, associated with the lipid bilayer by noncovalent interactions.

Lipid-anchored Proteins

Proteins that are covalently attached to lipids within the membrane.

Facilitated Diffusion

The process by which substances cross membranes with the assistance of special proteins without requiring energy.

Active Transport

The movement of substances across a membrane against their concentration gradient, requiring energy input.

Aquaporins

Channel proteins that facilitate rapid transport of water across cell membranes.

Glycolipids

Lipids with carbohydrate chains attached, found in cell membranes, important for cell recognition.

Phosphatidic Acid

A precursor to other phospholipids, composed of a glycerol backbone with two fatty acyl chains and one phosphate group.

Cholesterol

A type of lipid that stabilize membrane fluidity and is present in the cell membranes of certain animal cells.

Signal Transduction

The process by which a cell responds to external stimuli through membrane receptors and generates a cellular response.

Homeostasis

The maintenance of stable internal conditions in an organism, including membrane fluidity.

Diffusion

The spontaneous movement of substances from an area of higher concentration to an area of lower concentration.

Isotonic Solution

A solution in which the concentration of solutes is the same inside and outside the cell, resulting in no net movement of water.

Hypotonic Solution

A solution with a lower concentration of solutes compared to the cell, causing the cell to swell.

Hypertonic Solution

A solution with a higher concentration of solutes compared to the cell, causing the cell to shrink.

Signal Reception

The process by which ligand molecules bind to receptors on the plasma membrane, initiating a response in the cell.

Fluid Mosaic Model

A model that describes the structure of the plasma membrane as a mosaic of various components that are able to move freely.