Vocabulary

nucleus

The control center of a cell that contains genetic material.

microtubule

A component of the cytoskeleton, providing structural support and shape.

microfilaments

Thin filaments of the cytoskeleton involved in cell movement and shape.

centrioles

Cylindrical structures that play a role in cell division.

centrosome

Region in a cell that organizes microtubules and is involved in cell division.

basal body

Structure that anchors cilia and flagella to the cell.

cilia

Short hair-like structures on the cell surface involved in movement.

flagella

Long whip-like structures that enable movement in some cells.

rough endoplasmic reticulum

A network of membranes with ribosomes that synthesizes proteins.

smooth endoplasmic reticulum

A network of membranes involved in lipid synthesis and detoxification.

ribosomes

Molecular machines that synthesize proteins by translating mRNA.

Golgi body (Golgi apparatus)

Organelle that modifies, sorts, and packages proteins for secretion.

secretion vesicle

Membrane-bound sac that transports substances to the cell membrane for release.

lysosome

Cell organelle that contains enzymes for digestion and waste processing.

microbodies (peroxisome and glyoxysomes)

Organelles that contain enzymes for fatty acid breakdown and detoxification.

chloroplast

Organelle in plant cells that carries out photosynthesis.

mitochondrion

The powerhouse of the cell, generating ATP through respiration.

plastid (leucoplast and chromoplast)

Types of organelles in plant cells involved in storage and pigment synthesis.

kinetochore

Protein structure on a chromosome that attaches to spindle fibers during division.

centromere

A region of a chromosome where sister chromatids are joined and where kinetochores form.

microtubule organizing center

Region in the cell where microtubules are nucleated and organized.

spindle fibers

Filaments composed of microtubules that separate chromosomes during cell division.

cisternae

Flattened membrane-bound compartments in the Golgi apparatus.

cytoskeleton

A network of fibers that provides structure and shape to the cell.

autophagy

The process by which cells recycle their own organelles and proteins.

residual body

A cellular structure that contains indigestible material after lysosome action.

forming face

The side of the Golgi apparatus that receives vesicles from the endoplasmic reticulum.

maturing face

The side of the Golgi apparatus that releases processed vesicles.

hydrolytic enzymes (lipase, glycosidases, proteases, nucleases)

Enzymes that catalyze the breakdown of different biological macromolecules.

acrosome

A cap-like structure that covers the head of a sperm and contains enzymes for fertilization.

intermediate fibers

Filamentous proteins that provide structural integrity to cells.

tubulin

The protein subunit that makes up microtubules.

cytoplasm

The semi-fluid substance within the cell membrane, excluding the nucleus.

nuclear envelope

A double membrane that encloses the nucleus.

nucleoplasm

The gel-like substance within the nucleus.

vesicle

A small membrane-bound sac that transports substances within the cell.

plasma membrane

The outer boundary of a cell, regulating entry and exit of substances.

phospholipid

A molecule consisting of two fatty acids, a phosphate group, and a glycerol backbone, forming cell membranes.

lipid bilayer

A double layer of phospholipids that makes up the plasma membrane.

hydrophilic/hydrophobic regions

The polar (water-attracting) and nonpolar (water-repelling) parts of molecules like phospholipids.

transmembrane proteins

Proteins that span the lipid bilayer, aiding in transport and communication.

cholesterol

A lipid that stabilizes cell membranes and maintains fluidity.

glycoproteins

Proteins with carbohydrate groups attached, involved in cell recognition.

glycolipids

Lipids with carbohydrate groups attached, involved in cell recognition.

fluid mosaic model

A description of the plasma membrane structure as a mosaic of diverse protein molecules.

diffusion

The passive movement of particles from an area of higher concentration to lower concentration.

osmosis (hypertonic, isotonic, hypotonic)

The diffusion of water across a selectively permeable membrane; hypertonic has higher solute concentration, isotonic has equal, and hypotonic has lower.

facilitated diffusion

The process of passive transport of molecules across a membrane via a protein channel.

active transport (sodium-potassium pump)

The movement of ions against their concentration gradient, requiring energy.

coupled channels (symport and antiport)

Membrane transport mechanisms where one substance moves along with another in the same direction (symport) or opposite directions (antiport).

endocytosis

The process by which cells internalize substances, including phagocytosis, pinocytosis, and receptor-mediated endocytosis.

exocytosis

The process where substances are expelled from a cell by vesicle fusion with the plasma membrane.

gap junctions

Channels that allow communication and transport of ions and molecules between adjacent cells.

tight junctions

Connections between cells that prevent the movement of materials through the spaces between them.

anchoring junctions

Cell junctions that provide mechanical stability to tissues.

plasmodesmata

Channels that connect plant cells, allowing for transport of materials.

desmosomes

Junctions that anchor adjacent cells together in tissues.

phagosome

A vesicle formed around a particle engulfed by phagocytosis.

polysaccharide maltose

A disaccharide sugar formed from two glucose units.

enzymes

Biological catalysts that accelerate chemical reactions in living organisms.