Cell Organelles: Structure, Function, & Location(s)

Nucleus

Structure: Double membrane; contains DNA Function: Stores genetic information; controls gene expression Location: Eukaryotic cells

Nucleolus

Structure: Dense region inside nucleus Function: Produces rRNA and assembles ribosomal subunits Location: Inside nucleus

Ribosome

Structure: rRNA + proteins; no membrane Function: Protein synthesis Location: Cytoplasm, rough ER

Rough ER

Structure: Membrane network with ribosomes Function: Makes/folds proteins destined for secretion or membranes Location: Cytoplasm; continuous with nuclear envelope

Smooth ER

Structure: Membrane network without ribosomes Function: Lipid synthesis, detoxification, Ca2+Ca2+ storage Location: Cytoplasm

Golgi Apparatus

Structure: Stack of flattened membrane sacs Function: Modifies, sorts, and packages proteins/lipids Location: Cytoplasm

Lysosome

Membrane-bound sac with digestive enzymes Function: Digests macromolecules and worn-out cell parts Location: Cytoplasm

Vacuole

Structure: Membrane-bound compartment Function: Storage; water balance Location: Cytoplasm; especially large in plants

Mitochondrion

Structure: Double membrane; inner folds = cristae Function: Produces ATP through cellular respiration Location: Cytoplasm

Chloroplast

Structure: Double membrane; thylakoids Function: Photosynthesis Location: Plant/algal cells

Peroxisome

Structure: Membrane-bound compartment with enzymes Function: Breaks down fatty acids; detoxifies H2O2H2​O2​Location: Cytoplasm

Cytoskeleton

Structure: Protein fibers Function: Shape, movement, transport, organization Location: Throughout cytoplasm

Centrosome

Structure: Microtubule-organizing region Function: Organizes microtubules; important in cell division Location: Animal cells

Cell Wall

Structure: Rigid outer layer Function: Support and protection Location: Plants, fungi, bacteria

Plasma Membrane

Structure: Phospholipid bilayer + proteins Function: Controls what enters/leaves cell Location: All cells