AP BIO PARTS OF CELL

Nucleus

Membrane-bound organelle containing chromatin and nucleoplasm; stores genetic information and coordinates cellular activities such as growth and reproduction.

Nuclear Envelope

Double membrane with pores; protects the nucleus and regulates the passage of materials in and out.

Nuclear Lamina

Mesh of protein filaments lining the inner surface of the nuclear envelope; provides structural support and helps organize chromatin.

Nucleolus

Dense region within the nucleus, not membrane-bound; site of ribosomal RNA (rRNA) synthesis and ribosome assembly.

Ribosome

Complex of rRNA and proteins, can be free-floating or bound to the rough ER; synthesizes proteins by translating mRNA.

Smooth ER

Membranous tubules without ribosomes; synthesizes lipids, detoxifies drugs, and stores calcium ions.

Rough ER

Membranous tubules studded with ribosomes; synthesizes and processes proteins destined for secretion or membrane incorporation.

Vesicles (transport)

Small membrane-bound sacs; transport materials between organelles and to the cell membrane.

Golgi Apparatus

Stacked membranous sacs (cisternae); modifies, sorts, and packages proteins and lipids for secretion or delivery.

Lysosome

Membrane-bound organelle containing hydrolytic enzymes; digests macromolecules and recycles cellular components.

Vacuoles

Large, membrane-bound sacs; storage of substances, maintenance of turgor pressure in plant cells.

Mitochondria

Double-membraned organelle with inner folds (cristae); produces ATP through cellular respiration.

Chloroplasts

Double-membraned organelle containing thylakoids and stroma; conducts photosynthesis, converting light energy into chemical energy.

Peroxisome

Membrane-bound organelle with enzymes; breaks down fatty acids and detoxifies harmful substances.

Microtubules

Hollow tubes made of tubulin protein; provide structural support, facilitate intracellular transport, and form the mitotic spindle.

Intermediate Filaments

Fibrous proteins coiled into cables; provide mechanical support and maintain cell shape.

Microfilaments

Thin, flexible filaments made of actin; support cell shape, enable motility, and participate in muscle contraction.

Cell Motility

Actin filaments and myosin proteins; enable movement of the cell and its components.

Centrosomes

Microtubule-organizing center containing two centrioles; organizes microtubules and facilitates cell division.

Centrioles

Cylindrical structures made of microtubules; involved in the formation of spindle fibers during cell division.

Cilia

Short, hair-like structures made of microtubules; move fluids and particles across the cell surface.

Flagella

Long, whip-like structures made of microtubules; propel cells through liquid environments.

Basal Body

Structure at the base of cilia and flagella; anchors the cilium or flagellum and organizes its microtubules.

Dyneins

Motor proteins attached to microtubules; facilitate movement along microtubules, important for cilia and flagella motion.

Cell Wall

Rigid outer layer made of cellulose in plants, chitin in fungi; provides structure, support, and protection to the cell.

Plasmodesmata

Channels between plant cell walls; facilitate communication and transport of materials between adjacent plant cells.

Tight Junctions

Intercellular junctions formed by claudins and occludins; prevent leakage of substances between cells.

Desmosomes

Cell junctions anchored by intermediate filaments; provide mechanical strength and stability to tissues.

Gap Junctions

Channels made of connexin proteins; allow direct communication and transport of ions and small molecules between adjacent cells.