Biology- Chapter 3A: Plasma Membrane

phospholipid bilayer

a double layer of amphiphilic molecules that forms the primary component of cell membrane.

phospholipid molecule

a molecule consisting of a (hydrophilic) phosphate head and two (hydrophobic) fatty acid tails, essential for forming the phospholipid bilayer in cell membranes.

non-polar fatty acid tails

A pair of fatty acid chains which have no electrical charge and are hydrophobic (water fearing) and stay within the membrane itself.

polar phosphate head

A phosphate head is polar/ charged and hydrophilic (water loving) part of a phospholipid that is oriented towards the aqueous environment in the phospholipid bilayer.

hydrophobic

having a tendency to repel and be isolated in water.

hydrophilic

having a tendency to be attracted to and dissolve in water.

amphiphilic/ amphipathic

describes molecules with both hydrophilic and hydrophobic components (e.g whole phospholipid).

homeostasis

the tendency of an organism to maintain an optimal internal environment.

integral proteins

a protein that is permanently secured to the plasma membrane.

transmembrane proteins

an integral protein that spans the entire plasma membrane.

peripheral proteins

a protein that is temporarily attached to the plasma membrane.

cholesterol

a steroid alcohol (lipid molecule) that regulates the fluidity in plasma membranes.

the fluid mosaic model

the theory that describes how the plasma membrane is structured.

glycolipids

a phospholipid bound to a carbohydrate.

glycoproteins

a protein bound to a carbohydrate.

selectively permeable

a property of cell membranes that ensures only specific substances pass across them.