Animal cell organelles

Smooth Endoplasmic Reticulum (SER)

A tubular, membrane network without ribosomes. It synthesizes lipids, detoxifies drugs, and stores calcium ions.

Rough Endoplasmic Reticulum (RER)

A network of flattened sacs studded with ribosomes. It synthesizes and processes proteins destined for secretion or membranes.

Nucleolus

A dense region within the nucleus not bound by a membrane. It is the site of ribosomal RNA (rRNA) synthesis and ribosome assembly.

Chromatin

A complex of DNA and proteins found in the nucleus. It exists in relaxed form for gene expression and condenses into chromosomes during cell division.

Nuclear Envelope

A double lipid bilayer that surrounds the nucleus. It contains pores that regulate transport of RNA and proteins between the nucleus and cytoplasm.

Nucleus

A double-membrane organelle that houses the cell’s DNA. It controls gene expression and regulates cell growth, division, and metabolism.

Ribosome

A non-membrane bound complex of rRNA and proteins. It serves as the site of protein synthesis by translating mRNA into polypeptides.

Peroxisome

A small, membrane-bound organelle containing oxidative enzymes. It breaks down fatty acids, detoxifies harmful substances, and produces hydrogen peroxide, which is then degraded by catalase.

Lysosome

A membrane-bound sac containing hydrolytic enzymes. It digests macromolecules, old organelles, and foreign particles to recycle cellular components.

Centrioles

Cylindrical structures composed of microtubules, usually found in pairs. They organize microtubules during cell division and help form cilia and flagella.

Cytoskeletal Elements

A network of microtubules, microfilaments, and intermediate filaments in the cytoplasm. They maintain cell shape, enable movement, and organize intracellular transport.

Golgi Apparatus

A stack of flattened membranous sacs. It modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Plasma Membrane

A phospholipid bilayer embedded with proteins. It controls selective transport of substances in and out of the cell and facilitates cell signaling.

Mitochondrion

A double-membrane organelle with its own DNA and cristae (folded inner membrane). It generates ATP through aerobic respiration and regulates cell metabolism.