Cell - Types Of Cells, Prokaryotes And Eukaryotes, Cell Size And Numbers, The Structure And Function Of Cells - The structure of eukaryotes, Plant organelles, Vacuoles, Cell wall

KEY TERMS

Actin filament

—A type of cytoskeletal filament that has contractile properties.

Amyloplast

—A plant cell plastid that stores starch.

Centriole

—Paired structures consisting of micro-tubules; in animal cells, directs the plane of cell division.

Chloroplast

—Green organelle in higher plants and algae in which photosynthesis occurs.

Chromoplast

—A plant cell plastid that contains yellow and orange pigments.

Cilia

—Short projections consisting of microtubules that cover the surface of some cells and provide for movement.

Cisface

—The side (or "face") of the Golgi body that receives vesicles containing macromolecules.

Crista

—pl., cristae, the folds of the inner membrane of a mitochondrion.

Cytoplasm

—All the protoplasm in a living cell that is located outside of the nucleus, as distinguished from nucleoplasm, which is the protoplasm in the nucleus.

Cytoskeleton

—A network of assorted protein filaments attached to the cell membrane and to various organelles that makes up the framework for cell shape and movement.

Deoxyribonucleic acid (DNA)

—The genetic material of a cell that contains encoded instructions for the synthesis of proteins

Endoplasmic reticulum

—The network of membranes that extends throughout the cell; involved in protein synthesis and lipid metabolism.

Endosymbiotic theory

—A theory that proposes that mitochondria, chloroplasts, and other eukaryotic organelles originally arose within cells by symbiosis between a single-celled prokaryote and another prokaryote.

Eukaryotic cell

—A cell whose genetic material is carried on chromosomes inside a nucleus encased in a membrane. Eukaryotic cells also have organelles that perform specific metabolic tasks and are supported by a cytoskeleton which runs through the cytoplasm, giving the cell form and shape.

Flagellum

—Thread-like appendage of certain cells, such as sperm cells, which controls their locomotion.

Fluid-mosaic model

—The model that describes the nature of the plasma membrane; the "mosaic" portion describes the proteins embedded within the plasma membrane, and the "fluid" portion describes the fluidity of the plasma membrane.

Golgi body

—The organelle that manufactures, sorts, and transports macromolecules within a cell.

Granum

—Sacs within a chloroplast that contain photosynthetic enzymes.

Hydrophilic

—"Water-loving;" describes the phosphate portion of a phospholipid.

Hydrophobic

—"Water-hating;" describes the fatty acid portion of a phospholipid.

Intermediate filament

—A type of cytoskeletal filament that anchors organelles.

Lysosome

—A vesicle that contains digestive enzymes.

Matrix

—The inner space of a mitochondrion formed by cristae.

Microtubule

—A type of cytoskeletal filament; the component of centrioles, flagella, and cilia.

Mitochondrion

—The power-house of the cell; contains the enzymes necessary for the oxidation of food into energy.

Nuclear envelope

—The double membrane that surrounds the nucleus.

Nuclear pore

—Tiny openings that stud the nuclear envelope.

Nucleoid

—The region in a prokaryote where the cell's DNA is located.

Nucleolus

—The darker region within the nucleolus where ribosomal subunits are manufactured.

Nucleus

—The control center of a cell; contains the DNA.

Organelle

—A membrane-bounded cellular "organ" that performs a specific set of functions within a eukaryotic cell.

Peroxisome

—A vesicle that oxidizes fats and other substances and stores hydrogen peroxide.

Phospholipid

—A molecule consisting of a phosphate head and two fatty acid chains that dangle from the head; the component of the plasma membrane.

Phospholipid bilayer

—The double layer of phospholipids that compose the plasma membrane.

Photosynthesis

—In plants, the process in which carbon dioxide and water are converted to sugars.

Pili

—Short projections that assist bacteria in attaching to tissues.

Plasma membrane

—The membrane of a cell.

Plastid

—A vesicle-like organelle found in plant cells.

Prokaryote

—A cell without a true nucleus.

Protist

—A single-celled eukaryotic organism.

Ribonucleic acid

—RNA; the molecule translated from DNA in the nucleus that directs protein synthesis in the cytoplasm; it is also the genetic material of many viruses.

Ribosome

—A protein composed of two subunits that functions in protein synthesis.

Stroma

—The material that bathes the interior of chloroplasts in plant cells.

Surface area to volume ratio

—The relationship between the surface area provided by the plasma membrane to the volume of the contents of a cell.

Thylakoid

—A membranous structure that bisects the interior of a chloroplast.

Transface

—The side (or "face") of a Golgi body that releases macromolecule-filled vesicles for transport.

Tubulin

—A protein that comprises microtubules.

Vacuole

—Membrane-enclosed structure within cells which store pigments, water, nutrients, and wastes.

Vesicle

—A membrane-bound sphere that contains a variety of substances in cells.