Chapter 4

Question 1

Theory that all organisms consists of one or more cells, which are the basic units of life; all cells come from division of preexisting cells; and all cells pass hereditary material to offspring.

Answer 1

Cell Theory

Question 2

Semifluid substances enclosed by a cell’s plasma membrane.

Answer 2

Cytoplasm

Question 3

Of a eukaryotic cell, organelle with a double membrane that holds the cell’s DNA.

Answer 3

Nucleus

Question 4

Structure that carries out a specialized metabolic function inside a cell.

Answer 4

Organella

Question 5

A cell’s outermost membrane

Answer 5

Plasma Membrane

Question 6

A relationship in which the volume of an object increases with the cube of the diameter, and the surface area increases with the square.

Answer 6

Surface-to-Volume ratio

Question 7

Protein that helps cell stick together in animal tissues.

Answer 7

Adhesion Protein

Question 8

Model of a cell membrane as a two-dimensional fluid of mixed composition.

Answer 8

Fluid Mosaic

Question 9

Membrane protein that triggers a change in cell activity after binding to a particular substance.

Answer 9

Receptor Protein

Question 10

Protein that passively or actively assists specific ions or molecules across a membrane.

Answer 10

Transport Protein

Question 11

Community of microorganisms living within a shared mass of secreted slime.

Answer 11

Biofilm

Question 12

Rigid but permeable structure that surrounds the plasma membrane of some cells.

Answer 12

Cell Wall

Question 13

Long, slender cellular structure used for motility.

Answer 13

Flagellum

Question 14

Of a bacterium or archaean, region of cytoplasm where the DNA is concentrated.

Answer 14

Nucleoid

Question 15

A protein filament that projects from the surface of some prokaryotic cells.

Answer 15

Pilus

Question 16

Small circle of DNA in some bacteria and archaea.

Answer 16

Plasmid

Question 17

Organelle of protein synthesis.

Answer 17

Ribosome

Question 18

A double membrane that constitutes the outer boundary of the nucleus. Pores in the membrane control which substances can cross.

Answer 18

Nuclear Envelope

Question 19

In a cell nucleus, a dense, irregularly shaped region where ribosomal subunits are assembled.

Answer 19

Nucleolus

Question 20

Viscous fluid enclosed by the nuclear envelope.

Answer 20

Nucleoplasm

Question 21

Fluid-filled vesicle in many plant cells.

Answer 21

Central Vacuole

Question 22

Series of interacting organelles between nucleus and plasma membrane; produce lipids, proteins.

Answer 22

Endomembrane System

Question 23

Organelle that is a continuous system of sacs and tubes extending from the nucleus envelope. Smooth ER makes lipids and breaks down carbohydrate and fatty acids; ribosomes on the surface of rough ER synthesize proteins

Answer 23

Endoplasmic Reticulum

Question 24

Organelle that modifies proteins and lipids, then package the finished products into vesicles.

Answer 24

Golgi body

Question 25

Enzyme-filled vesicle that breaks down cellular wastes and debris.

Answer 25

Lysosome

Question 26

Enzyme-filled vesicle that breaks down amino acids, fatty acids, and toxic substances.

Answer 26

Peroxisome

Question 27

A fluid-filled organelle that isolates or disposes of waste, debris, or toxic materials.

Answer 27

Vacuole

Question 28

Small, membrane-enclosed organelle; different kinds store, transport, or break down their contents.

Answer 28

Vesicle

Question 29

Organelle of photosynthesis in the cells of plants and photosynthetic protists.

Answer 29

Chloroplast

Question 30

One of several types of double-membraned organelles in plants and algae cells; for example, a chloroplast or amyloplast.

Answer 30

Plastid

Question 31

Organelle that develops from a centriole.

Answer 31

Basal Body

Question 32

Mesh of cytoskeletal elements under a plasma membrane.

Answer 32

Cell Cortex

Question 33

Barrel-shaped organelle from which microtubules grow.

Answer 33

Centriole

Question 34

Short, movable structure that projects from the plasma membrane of some eukaryotic cells.

Answer 34

Cilium

Question 35

Network of interconnected protein filaments that support, organize, and move eukaryotic cells and their parts.

Answer 35

Cytoskeleton

Question 36

Stable cytoskeletal elemental that is a fiber of actin subunits. Reinforces cell membranes; functions in muscle contractions.

Answer 36

Microfilament

Question 37

Cytoskeletal element involved in movement; hollow filament of tubulin subunits.

Answer 37

Microtubule

Question 38

Type of energy-using protein that interacts with cytoskeletal elements to move the cell's parts or the whole cell.

Answer 38

Motor protein

Question 39

A temporary protrusion that helps some eukaryotic cells move and engulf prey.

Answer 39

Pseudopod

Question 40

Cell junction composed of adhesion proteins that connect to cytoskeletal elements. Fastens cells to each other and basement membrane.

Answer 40

Adhering Junction

Question 41

Structure that connects a cell to another cell or to extracellular matrix.

Answer 41

Cell Junction

Question 42

Secreted covering at a body surface.

Answer 42

Cuticle

Question 43

Complex mixture of cell secretions; its composition and function vary by cell type.

Answer 43

Extracellular Matrix (ECM)

Question 44

Cell junction that forms a closable channel across the plasma membranes of adjoining animal cells.

Answer 44

Gap Junction

Question 45

Material that strengthens cell walls of vascular plants.

Answer 45

Lignin

Question 46

Cell junctions that form an open channel between the cytoplasm of adjacent plant cells.

Answer 46

Plasmodesmata

Question 47

The first cell wall of young plant cells.

Answer 47

Primary Wall

Question 48

Lignin-reinforced wall that forms inside the primary wall of a plant cell.

Answer 48

Secondary Wall

Question 49

Arrays of adhesion proteins that join epithelial cells and collectively prevent fluids from leaking between them.

Answer 49

Tight Junctions