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 use molecular oxygen to detoxify harmful or toxic substances, such as free radicals.

Cytoskeleton

• literally, cell skeleton; 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

• the 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 with a movement toward uniform distribution of particles; 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 that has an elongated shape, like the cable-like fibers it secretes. It has an abundant rough ER and a large Golgi apparatus to make and secrete the protein building blocks of these fibers.

Erythrocyte

• red blood cells.

Epithelial cell

• Cell with Hexagonal shape which allows epithelial cells to pack together in sheets. Has abundant intermediate filaments and desmosomes that resist tearing when the epithelium is rubbed or pulled.

Fat cell

• The huge spherical shape of a fat cell is produced by a large lipid droplet in its cytoplasm.

Macrophage

• cell particularly abundant in lymphatic and connective tissues; important in the immune response as an antigen presenter to T cells and B cells.

Nerve cell (neuron)

• cells of the nervous system specialized to transmit messages throughout the body.

Oocyte

• an immature egg.