Nucleus:

• Structure: Membrane-bound organelle containing chromatin and nucleoplasm.

• Function: Stores genetic information and coordinates cellular activities such as growth and reproduction.

Nuclear Envelope:

• Structure: Double membrane with pores.

• Function: Protects the nucleus and regulates the passage of materials in and out.

Nuclear Lamina:

• Structure: Mesh of protein filaments lining the inner surface of the nuclear envelope.

• Function: Provides structural support and helps organize chromatin.

Nucleolus:

• Structure: Dense region within the nucleus, not membrane-bound.

• Function: Site of ribosomal RNA (rRNA) synthesis and ribosome assembly.

Ribosome:

• Structure: Complex of rRNA and proteins, can be free-floating or bound to the rough ER.

• Function: Synthesizes proteins by translating mRNA.

Smooth ER:

• Structure: Membranous tubules without ribosomes.

• Function: Synthesizes lipids, detoxifies drugs, and stores calcium ions.

Rough ER:

• Structure: Membranous tubules studded with ribosomes.

• Function: Synthesizes and processes proteins destined for secretion or membrane incorporation.

Vesicles (transport):

• Structure: Small membrane-bound sacs.

• Function: Transport materials between organelles and to the cell membrane.

Golgi Apparatus:

• Structure: Stacked membranous sacs (cisternae).

• Function: Modifies, sorts, and packages proteins and lipids for secretion or delivery.

Lysosome:

• Structure: Membrane-bound organelle containing hydrolytic enzymes.

• Function: Digests macromolecules and recycles cellular components.

Vacuoles:

• Structure: Large, membrane-bound sacs.

• Function: Storage of substances, maintenance of turgor pressure in plant cells.

Mitochondria:

• Structure: Double-membraned organelle with inner folds (cristae).

• Function: Produces ATP through cellular respiration.

Chloroplasts:

• Structure: Double-membraned organelle containing thylakoids and stroma.

• Function: Conducts photosynthesis, converting light energy into chemical energy.

Peroxisome:

• Structure: Membrane-bound organelle with enzymes.

• Function: Breaks down fatty acids and detoxifies harmful substances.

Microtubules:

• Structure: Hollow tubes made of tubulin protein.

• Function: Provide structural support, facilitate intracellular transport, and form the mitotic spindle.

Intermediate Filaments:

• Structure: Fibrous proteins coiled into cables.

• Function: Provide mechanical support and maintain cell shape.

Microfilaments:

• Structure: Thin, flexible filaments made of actin.

• Function: Support cell shape, enable motility, and participate in muscle contraction.

Cell Motility:

• Structure: Actin filaments and myosin proteins.

• Function: Enable movement of the cell and its components.

Centrosomes:

• Structure: Microtubule-organizing center containing two centrioles.

• Function: Organizes microtubules and facilitates cell division.

Centrioles:

• Structure: Cylindrical structures made of microtubules.

• Function: Involved in the formation of spindle fibers during cell division.

Cilia:

• Structure: Short, hair-like structures made of microtubules.

• Function: Move fluids and particles across the cell surface.

Flagella:

• Structure: Long, whip-like structures made of microtubules.

• Function: Propel cells through liquid environments.

Basal Body:

• Structure: Structure at the base of cilia and flagella.

• Function: Anchors the cilium or flagellum and organizes its microtubules.

Dyneins:

• Structure: Motor proteins attached to microtubules.

• Function: Facilitate movement along microtubules, important for cilia and flagella motion.

Cell Wall:

• Structure: Rigid outer layer made of cellulose in plants, chitin in fungi.

• Function: Provides structure, support, and protection to the cell.

Plasmodesmata:

• Structure: Channels between plant cell walls.

• Function: Facilitate communication and transport of materials between adjacent plant cells.

Tight Junctions:

• Structure: Intercellular junctions formed by claudins and occludins.

• Function: Prevent leakage of substances between cells.

Desmosomes:

• Structure: Cell junctions anchored by intermediate filaments.

• Function: Provide mechanical strength and stability to tissues.

Gap Junctions:

• Structure: Channels made of connexin proteins.

• Function: Allow direct communication and transport of ions and small molecules between adjacent cells.