Chapter 4: Key Terms

Question 0

Cell Wall

Answer 0

A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists; protects the cell and helps maintain its shape

Question 1

Cell Theory

Answer 1

The theory that all living things are composed of cells and that all cells come from other cells

Question 2

Cellular Metabolism

Answer 2

The chemical activities of cells

Question 3

A structure in an animal cell composed of cylinders of microtubule triplets arranged in a 9 and 0 pattern. An animal usually has a centrosome with a pair of centrioles involved in cell division

Answer 3

Centriole

Question 4

Chloroplast

Answer 4

An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic molecules (sugars) from carbon dioxide and water

Question 5

The complex of DNA and proteins that constitutes eukaryotic chromosomes; often used to refer to the diffuse, very extended form taken by chromosomes when a cell is not dividing

Answer 5

Chromatin

Question 6

A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis; also, the main gene-carrying structure of a prokaryotic cell. Chromosomes consist of chromatin, a combination of DNA and protein

Answer 6

Chromosome

Question 7

A membrane-enclosed sac occupying most of the interior of a mature plant cell, having diverse roles in reproduction, growth, and development

Answer 7

Central Vacuole

Question 8

Cytoplasm

Answer 8

Everything inside a cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles

Question 9

A network of protein fibers in the cytoplasm of a eukaryotic cell; includes microfilaments, intermediate filaments, and microtubules

Answer 9

Cytoskeleton

Question 10

Electron Microscope (EM)

Answer 10

An instrument that focuses an electron beam through, or onto the surface of, a specimen. An electron microscope achieves a hundredfold greater resolution than a light microscope

Question 11

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles

Answer 11

Endomembrane System

Question 12

Crista

Answer 12

An infolding of the inner membrane of a mitochondrion in which is embedded the electron transport chain and the enzyme catalyzing the synthesis of ATP

Question 13

A process by which the mitochondria and chloroplasts of eukaryotic cells probably evolved from symbiotic associations between small prokaryotic cells living inside larger cells

Answer 13

Endosymbiosis

Question 14

A type of cell that has a membrane-enclosed nucleus and other membrane-enclosed organelles. All organisms except bacteria and archaea are composed of eukaryotic cells

Answer 14

Eukaryotic Cell

Question 15

A substance in which the cells of an animal tissue are embedded; consists of protein and polysaccharides

Answer 15

Extracellular Matrix (ECM)

Question 16

An extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions

Answer 16

Endoplasmic Reticulum

Question 17

A macromolecule consisting of one or more polypeptides linked to short chains of sugars

Answer 17

Glycoprotein

Question 18

An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the endoplasmic reticulum

Answer 18

Golgi Apparatus

Question 19

A long cellular appendage specialized for locomotion. The flagella of prokaryotes and eukaryotes differ in both structure and function. Like cilia, eukaryotic flagella have a 9 + 2 arrangement of microtubules covered by the cell’s plasma membrane

Answer 19

Flagellum

Question 20

A stack of hollow disks formed of thylakoid membrane in a chloroplast. Grana are the sites where light energy is trapped by chlorophyll and converted to chemical energy during the light reactions of photosynthesis

Answer 20

Granum

Question 21

An intermediate-sized protein fiber that is one of the three main kinds of fibers making up the cytoskeleton of eukaryotic cells. Intermediate filaments are ropelike, made of fibrous proteins

Answer 21

Intermediate Filament

Question 22

An optical instrument with lenses that refract (bend) visible light to magnify images and project them into a viewer’s eye or onto photographic film

Answer 22

Light Microscope (LM)