AP Biology: Lipids & Cell Membrane Vocab

phospholipid

phospholipid

a lipid that contains phosphorus and that is a structural component in cell membranes

phospholipid bilayer

a spontaneous arrangement of phospholipids with hydrophilic heads extending outwards and hydrophobic tails inwards when surrounded by water/ A double layer of phospholipids that makes up plasma and organelle membranes.

hydrophobic

Water fearing

hydrophilic

water loving

amphipathic

molecules with a hydrophilic & hydrophobic part

fatty acid

any long chain of hydrocarbon, with a single carboxylic group and aliphatic tail (aliphatic referring to if it has at least 1 double bond, or 1 triple bond or just single bonds between carbons)

saturated fatty acid

a fatty acid in which the hydrocarbon chain has only single bonds between carbons

unsaturated fatty acid

a fatty acid in which the hydrocarbon chain consists of at least 1 double bond between carbons

micelle

the spherical arrangement of phospholipids when placed in water

selectively permeable

a property of cell membranes that allows some substances to pass through, while others cannot

diffusion

the passive movement of molecules from a higher to a lower concentration until equilibrium is reached

osmosis

the passive movement of water molecules from an area of high water potential to an area of low water potential across a selectively permeable membrane until equilibrium is achieved

passive transport

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

aquaporins

specialized channel proteins that transport water`

glycolipid

a lipid with one or more covalently attached carbohydrates

glycoprotein

A protein with one or more covalently attached carbohydrates.

Channel proteins

integral proteins that create holes/pores that penetrate the membrane, enabling target molecules or ions to flow through via diffusion without interfering with one another

Carrier proteins

integral proteins that bind to molecules or ions on one side of the membrane and release them on the other.

symport

type of transport in which 2 kinds of molecules can move simultaneously across a cell membrane in the same direction

generalized fatty acid

a long-chain hydrocarbon with a carboxyl group (COOH) at one end. The basic structure consists of a hydrocarbon tail and a polar carboxyl group, which makes it an amphipathic molecule

antiport

A membrane transport process that carries one substance in one direction and another in the opposite direction.

uniport

A type of transport that moves one substance across a membrane in one direction only down their concentration gradient

triglyceride

a lipid made of three fatty acid molecules and one glycerol molecule

transmembrane proteins

Integral proteins that span the membrane.

peripheral proteins (extrinsic proteins)

The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.

integral proteins (intrinsic proteins)

amphipathic proteins that are embedded in the whole bilayer

fluid mosaic model

describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character

ester bond

forms when the hydroxyl (-OH) group of the glycerol bonds with the carboxyl group (-COOH) of the fatty acid

phosphoester bond

a bond between the phosphorus atom of a phosphate group and an oxygen atom

ester

organic compounds formed by combing alcohol with carboxylic acid

endocytosis

cellular process where a cell engulfs and internalizes substances from the external environment

types:

~phagocytosis (engulfing large particles)

~receptor-mediated endocytosis (selective uptake of specific molecules through receptor interactions)

~pinocytosis (ingesting small fluid droplets)

exocytosis

cellular mechanism responsible for the release of substances from a cell to the extracellular environment

facilitated diffusion

the passive movement of molecules along the concentration gradient (requires channel proteins)

active transport

Energy-requiring process that moves material across a cell membrane against a concentration gradient (uses carrier proteins)