Antibotic

A chemical that can slow or stop the growth of bacteria; many antibiotics are produced by living organisms. 

Cell Theory 

The concept that all living organism are made of cells and that cells are formed by the reproduction of existing cells.

Prokaryotic Cells

Cells that lack internal membrane-bound organelles.

Eukaryotic Cells

Cells that contain membrane-bound organelles, including a central nucleus.

Organelles

The membrane-bound compartments of eukaryotic cells that carry out specific functions.

Cell Membrane

A phospholipid bilayer with embedded proteins that forms the boundary of all cells. 

Cytoplasm

The gelatinous, aqueous interior of all cells.

Ribosome

A complex of RNA and protein that carries out protein synthesis in all cells. 

Nucleus

Osmosis

The diffusion of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Peptidoglycan

A macromolecule that forms all bacterial cell walls and probides regidity to the cell wall. 

Cell Wall  

A rigid structure enclosing teh cell membrane of some cells that hels the cell maintain its shape.

Gram-Positive

Refers to bacteria with a cell wall that includes a thick layer of peptidoglycan that retains the Gram stain.

Gram-Negative

Refers to bacteria with a cell wall that includes a thin layer of peptidoglycan surrounded by an outer lipid membrane that does not retain the 

Gram stain.

Simple Diffusion

The movement of small, hydrophobic molecules across a membrane from an area of higher concentration to an area of lower concentration; simple diffusion does not require energy.

Transport Proteins

Proteins involved in the movement of molecules across the cell membrane. 

Facilitated Diffusion

The process by which large or hydrohilic solutes move across a membrane from an area of higher concentration to an area of lower concentration with the help of tracnsport proteins. 

Active Transport

The energy-requiring process by which solutes are pumped from an area of lower concentration to an area of higher concentration with the help of transport proteins. 

Nuclear Envelope

The double membrane surrounding the nucleus of a eukaryotic cell. 

Mitochondria 

Membrane-bound organelles reponsible for inportant energy-conversion reations in eukaryotes. 

Endoplasmic Reticulum

A membrane-enclosed seriers of passages in eukaryotic cells in which proteins and lipids are synthesized. 

Golgi Apparatus

An organelle made up of stacked membrane enclosed discs that packages proteins and prepares them for transport

Chloroplast

An organelle in plant and algal cells that is the site of photosynthesis

Lysosome

An organelle in eukaryotic cells filled with enzymes that an degrade worn-out cellular structures. 

Cytoskeleton

A network of protein fivers in eukaryotic cells that provides structure and facilitates cell movement. 

Endosymbiosis

The theory that freeliving prokaryotic cells engulfed other freeliving prokaryotic cells billions of years ago, forming eukaryotic organelles such as mitochondria and chloroplasts.