AP Bio Cell Organelles

Prokaryote

A microscopic, single-celled organism that lacks a distinct cell nucleus and other membrane-bound organelles

Nucleoid

An irregularly shaped region inside a prokaryotic cell (like bacteria) that contains genetic material

Eukaryote

A type of cell that has a distinct, membrane-bound nucleus and other specialized, internal compartments called organelle

Cell membrane

A thin, flexible barrier that surrounds all living cells and separates its inside from the outside environment; controls what moves in and out

Mitochondria

Highly folded, double-membrane cell organelles found in nearly all eukaryotic organisms that generate most of the chemical energy needed to power the cell’s biochemical reactions; synthesizes ATP, apoptosis, calcium storage, and generates heat

Chloroplast

Double-membrane organelle found in plants and algae that contain chlorophyll, location of photosynthesis; converts sunlight into chemical energy, produces sugar, releases oxygen

Lysosomes

A single-membrane cell organelle filled with digestive enzymes that act as the cell’s waste disposal and recycling system; aids in apoptosis and digestion of unneeded macromolecules/old cell parts/debris

Peroxisomes

Small, single-membrane cellular organelles found in the cytoplasm of virtually all eukaryotic cells; breaks down toxic substances and fatty acids, produces hydrogen peroxide

Cytosol

Water-based, jelly-like fluid that fills the space inside a cell and surrounds the internal structures (only the fluid part of the cell); site for chemical reactions, transportation, keeps organelles in place, helps pass chemical signals from the cell membrane to the inner organelles

Flagellum

Long, whip-like appendage that helps microscopic cells and organisms move through liquid; propels a cell forward, sensory role

Centrosome

Small, non-membrane-bound organelle found in animal cells that acts as the main microtubule-organizing center; organizes microtubules and plays an important role in cell division and chromosome separation

Cytoskeleton

An organized network of protein filaments and tubules that extends throughout the cytoplasm of a living cell; maintains cell shape, moves organelles, allows cell movement, and helps with cell division

Microfilaments

The thinnest fibers of the cytoskeleton, made mainly of the protein actin; maintains cell shape, helps cell movement, helps contract muscles, transports materials within cells, and helps with cell division

Microtubules

Thicket fibers of the cytoskeleton (hollow, tube-shaped structures), made of the protein tubulin; helps with cell shape and support, cell movement, cell division, and intracellular transport

Microvilli

Tiny, finger-like extensions of the cell membrane supported by microfilaments that increase the cell’s surface area; increases surface area and helps with digestion, nutrient absorption, and cell adhesion

Nucleus

Large double-membrane command center found in eukaryotic cells; stores DNA, controls gene expression, makes RNA, builds ribosomes, and directs cell division

Nuclear envelope

Double-membrane layer that surrounds and protects the nucleus, separating the nucleus from the cytoplasm; protects DNA and regulates transport through nuclear pores

Nucleolus

A dense, non-membrane-bound region inside the nucleus where ribosomes are produced; makes rRNA and assembles ribosomal subunits

Chromatin

A complex mixture of DNA, RNA, and proteins found in the cell nucleus; stores genetic information, packages DNA into a compact form, regulates gene expression, and forms chromosomes

Endoplasmic Reticulum

Large network of folded membranes and tubules in the cytoplasm; helps make and transport proteins and lipids

Rough ER

A cellular organelle made of folded membranes covered in ribosomes; makes, folds, modifies, and transports proteins

Smooth ER

Network of tubular membranes inside eukaryotic cells that lacks ribosomes on its surface; makes lipids, produces steroids, detoxifies substances, and stores calcium ions

Ribosomes

Small non-membrane-bound structures made of rRNA and proteins that are responsible for making proteins; builds proteins by reading mRNA and joins amino acids together

Cell wall

A rigid, protective outer layer that surrounds the cell membrane in plants and bacteria; protects cell from damage, provides structural support, maintains cell shape, regulates pressure/prevents cell from bursting, and filtrates

Plasmodesmata

Microscopic channels that cross the cell walls of plants and connect the cytoplasm of neighboring cells; transports substances, helps with cell communication, and connects plant cells

Central vacuole

A large, fluid-filled organelle found in plant cells; stores water and other substances, provides turgor pressure, and helps isolate waste

Golgi apparatus

A single-membrane-bound cell organelle; modifies, sorts, and packages proteins and lipids for transport

Vesicles

Small, spherical organelle enclosed by a lipid bilayer; transports materials between organelles, stores substances, secretes substances, and brings substances into the cell

Glycoproteins

Proteins with carbohydrates attached to them; helps with cell recognition, cell communication, immune response, and cell adhesion

Food vacuoles

A membrane-bound cellular compartment that forms during the ingestion of food and functions as an intracellular site for digesting nutrients and distributing them into the cell; stores and digests food, provides nutrients that the cell can use