Vocabulary Quiz 1 (CH.3)

Nucleus

A dense central body in most cells containing the genetic material of the cell; cluster of neuronal cell bodies in the brain or spinal cord.

Chromatin

The structures in the nucleus that carry the hereditary factors (genes).

Plasma membrane

Membrane that encloses cell contents; outer limiting membrane.

Hydrophilic

Refers to molecules, or portions of molecules, that interact with water and charged particles.

Hydrophobic

Refers to molecules, or portions of molecules, that interact only with nonpolar molecules.

Cytoplasm

The substance of a cell other than that of the nucleus.

Organelles

Specialized structures in a cell that perform specific metabolic functions.

Mitochondria

The rod-like cytoplasmic organelles responsible for ATP generation.

Ribosomes

Cytoplasmic organelles at which proteins are synthesized.

Endoplasmic reticulum

A membranous network of tubular or saclike channels in the cytoplasm of a cell.

Golgi apparatus

Membrane-bound organelle responsible for modifying, packaging, and shipping proteins produced by rough ER to the appropriate destination.

Lysosomes

Organelles that originate from the Golgi apparatus and contain strong digestive enzymes.

Peroxisomes

Membranous sacs in the cytoplasm containing powerful oxidase enzymes that detoxify harmful or toxic substances.

Cytoskeleton

Internal framework of proteins that determine cell shape.

Cilia

Tiny, hairlike projections on cell surfaces that move in a wavelike manner.

Flagella

Long, whiplike extensions of the cell membrane of some bacteria and sperm; serve to propel the cell.

Microvilli

Tiny projections on the free surfaces of some epithelial cells; increase surface area for absorption.

Selective permeability

Characteristic exhibited by a barrier, such as a membrane, that allows some substances through and excludes others.

Diffusion

The spreading of particles in a gas or solution toward uniform distribution; also called simple diffusion.

Sodium-potassium pump

Carries sodium ions out of and potassium ions into the cell.

Exocytosis

Method for the movement of substances from the cell interior to the extracellular space as a secretory vesicle fuses with the plasma membrane.

Endocytosis

Means by which fairly large extracellular molecules or particles enter cells.

Phagocytosis

The ingestion of solid particles by cells.

Fibroblast

Cell with an elongated shape that secretes cable-like fibers; has abundant rough ER and a large Golgi apparatus.

Erythrocyte

Red blood cells.

Epithelial cell

Cell with a hexagonal shape that allows packing together in sheets; has abundant intermediate filaments and desmosomes.

Fat cell

Huge spherical shape produced by a large lipid droplet in its cytoplasm.

Macrophage

Cell abundant in lymphatic and connective tissues; important in the immune response as an antigen presenter.

Nerve cell (neuron)

Cells of the nervous system specialized to transmit messages throughout the body.

Oocyte

An immature egg.