Allele Biology-Online.org Definition noun, plural: alleles (genetics) One member of a pair (or any of the series) of genes occupying a specific spot on a chromosome (called locus) that cont

Allele Wikipedia.org An allele is one of two or more forms of the DNA sequence of a particular gene.[1][2] Visit the website for the article.

What is ATP? Wiki Answers ATP is produced by almost all living things in their cell's organelles called mitochondria. It stands for adenosine triphosphate and it is the major 'currency' of energy

Cell Biology: receptor proteins Biology of Cells Blog Biologically active molecules (ligands) exert their physiological effect by activating or inducing 3D conformational changes in receptor pro

Cell Organelles A Review of the Universe Universe-review.ca Function of organelles in a table format; scroll down for a good illustration.

Cell Organelles Biology-Online.org noun, plural: cell organelles A membrane-bound compartment or structure in a cell that performs a special function. Visit the web site for supplemental inf

CELL ORGANELLES: microtubules Russell Kightley Media Canberra, Australia In this picture, microtubules are the pale spoke-like structures. They originate near the centre of the cell at the cent

centriole By David Darling DavidDarling.info Brief encyclopedia article, with illustration.

Centrosome Wikipedia.org In cell biology, the centrosome is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell as well as a regulator of cell-cycle prog

channel protein Answers.com (cell and molecular biology) Protein forming an aqueous pore spanning the lipid bilayer of the cell membrane which when open allows certain solutes to traverse the me

Chloroplasts Georgia State University Two nice sketches and description of chloroplasts and its parts.

chromosome By David Darling DavidDarling.info Encyclopedia article, with illustrations. You can all access articles on genetics and heredity on this page.

Chromosome Structure By John Kyrk Animated outline of chromosome structure; probably best for advanced students but interesting to watch.

What Are Cilia? Written by S. Mithra Wisegeek.com Cilia is Latin for "eyelash." Common in single-cell organisms, this hair-like structures wave to move a cell around, or to move something around

Cytoplasm By David Darling The jelly-like matrix that surrounds the nucleus of a cell and is bounded by the cell membrane. It includes the organelles of the cell as well as the sugars, amino

Cytoplasm Definition By Nature Education All-text definition; links to other concepts for further exploration.

cytoskeleton By David Darling DavidDarling.info Encyclopedia article on the three protein systems that constitute the cytoskeleton.

Cytoskeleton Tutorial The Biology Project Department of Biochemistry and Molecular Biophysics University of Arizona Find out what the cytoskeleton is and what it does in this tutorial.

Diffusion Definition Dennis Anderson, Professor of Biology Oklahoma City Community College Illustrations and text explaining the movement of molecules from a high concentration to low concentra

Endocytosis and Exocytosis Animation Max Animations Visit the web site to learn what endocytosis and exocytosis are and an animation.

Endoplasmic reticulum Biology-Online.org An important organelle heavily involved in protein synthesis. This page has a definition with links to more in-depth information.

eukaryotic cell By David Darling Excellent article on eurkaryotic cells origin and structure. It also has a side-by-side comparison of eukaryotic and prokaryotic cells. Includes images.

exocytosis By David Darling The Encyclopedia of Science Visit the website for a brief article.

Flagellum By David Darling A whip-like organelle specialized for locomotion. Flagella are found among all three domains of life - bacteria, archaea, and eukaryotes - but the structure of the appen

Gap junction Wikipedia.org A gap junction or nexus is a specialized intercellular connection between a multitude of animal cell-types. Visit the website for a diagram and the rest of the arti

Golgi apparatus By David Darling Also known as the Golgi body or Golgi complex, a collection of vesicles and folded membranes in a cell, usually connected to the endoplasmic reticulum (ER). It s

lysosome By David Darlings DavidDarling.info Encyclopedia article on lysosomes, with a great illustration.

Membrane Transport Protein Biology Online A type of [[protein that actively transports materials across a [[cell membrane that would not otherwise allow this to occur.

Microtubule Wikipedia.org Microtubules are one of the components of the cytoskeleton. They have a diameter of 25 nm and length varying from 200 nanometers to 25 micrometers. Microtubules serve a

mitochondria By David Darling DavidDarling.info Encyclopedia article with illustrations.

Molecular Expressions Cell Biology: Microfilaments by Michael W. Davidson and The Florida State University Microfilaments are solid rods made of globular proteins called actin. These filaments a

Nucleoid Biology-Online.org The portion within a prokaryotic cell where the genetic material is to be found. Visit the web site for supplemental information.

Nucleolus By David Darling DavidDarling.info Brief description and illustration of the nucleolus.

Nucleolus Biology Online The round granular structure within the nucleus of a cell, and composed of protein and RNA. Visit the website for supplemental information.

Nucleus Biology-Online.org Definition of the nucleus with links to more in-depth information.

Organelle Wikipedia.org Extensive article on organelles; click on image to enlarge.

Osmosis Wikipedia.org Combination of text and illustrations explaining the process of osmosis.

Peripheral membrane protein Biology Online A protein that temporarily adheres to the biological membrane, either to the lipid bilayer or to integral proteins by a combination of hydrophobic, ele

Phagocyte Wikipedia.org Phagocytes are the white blood cells that protect the body by ingesting (phagocytosing) harmful foreign particles, bacteria, and dead or dying cells. Visit the websit

Pinocytosis Biology-Online.org Pinocytosis is a process that enables a cell to take in fluid through its membrane. Visit the website for a definition and supplemental information.

Plasma Membrane By Dennis Anderson, Biology Professor Oklahoma City Community College An illustration of the plasma membrane; it regulate what goes in and out of a cell.

Prokaryote Wikipedia.org A good description of prokaryote plus a good illustration; click on image to enlarge.

Pyruvic Acid Biology-Online.org A colorless, water-soluble, organic liquid produced by the breakdown of carbohydrates and sugars during glycolysis, and with a chemical formula of: CH3COCO2H.

ribosome By David Darling DavidDarling.info Encyclopedia article on ribosomes, with illustrations.

Ribosome Scitable By Nature Education All-text definition; links to other topics for further exploration.

Simple Diffusion Brooklyn College City University of New York Illustration and description of simple diffusion.

SparkNotes: Cell Membranes: The Lipid Layer Good article; includes illustrations.

Tight junction Wikipedia.org Article with images on the structure, function, and classification of tight junctions; click on the diagram for a closer look.

Vesicle Budding and Fusing W. W. Norton & Co. and Sumanas, Inc. An animation showing how vesicles transport molecules from one place to another. After you view the animation, there's an option t