Chapter 7

Question 1

The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient.

Answer 1

Cotransport

Question 2

A molecule that binds specifically to another molecule, usually a larger one.

Answer 2

Ligands

Question 3

A type of endocytosis in which large particulate substances are taken up by a cell.

Answer 3

Phagocytosis

Question 4

The cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane.

Answer 4

Exocytosis

Question 5

An ion transport protein that generates voltage across a membrane.

Answer 5

Electrogenic Pump

Question 6

A transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell.

Answer 6

Sodium-Potassium Pump

Question 7

A transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient.

Answer 7

Ion Channels

Question 8

A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment.

Answer 8

Plasmolysis

Question 9

Swollen or distended, as in plant cells. (A walled cell becomes _____ if it has a greater solute concentration that its surroundings, resulting in the entry of water.)

Answer 9

Turgid

Question 10

Referring to a solution that, when surrounding a cell, will cause the cell to take up water.

Answer 10

Hypotonic

Question 11

Referring to a solution that, when surrounding a cell, has no effect on the passage of water into or out of the cell.

Answer 11

Isotonic

Question 12

The diffusion of a substance across a biological membrane with no expenditure of energy.

Answer 12

Passive Transport

Question 13

The spontaneous movement of a substance down its concentration gradient, from a region where it is more concentrated to a region where it is less concentrated.

Answer 13

Diffusion

Question 14

A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.

Answer 14

Transport Proteins

Question 15

A lipid with covalently attached carbohydrates.

Answer 15

Glycolipids

Question 16

Typically a transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on either side of the membrane (or lining the channel in the case of a channel protein).

Answer 16

Integral Proteins

Question 17

Having both a hydrophilic region and a hydrophobic region.

Answer 17

Amphipathic

Question 18

A property of biological membranes that allows them to regulate the passage of substances.

Answer 18

Selective Permeability

Question 19

The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids.

Answer 19

Fluid Mosaic Model

Question 20

A protein loosely bound to the surface of a membrane or part of an integral protein and not embedded in the lipid bilayer.

Answer 20

Peripheral Proteins

Question 21

A protein with one or more carbohydrates covalently attached to it.

Answer 21

Glycoproteins

Question 22

A channel protein in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of water across the membrane.

Answer 22

Aquaporins

Question 23

A region along which the density of a chemical substance increases or decreases.

Answer 23

Concentration Gradient

Question 24

The diffusion of water across a selectively permeable membrane.

Answer 24

Osmosis

Question 25

Referring to a solution that, when surrounding a cell, will cause the cell to lose water.

Answer 25

Hypertonic

Question 26

Regulation of solute concentrations and water balance by a cell or organism.

Answer 26

Osmoregulation

Question 27

Limp. Lacking in stiffness or firmness, as in a plant cell in surroundings where there is no tendency for water to enter the cell.

Answer 27

Flaccid

Question 28

The spontaneous passage of molecules or ions across a biological membrane with the assistance of specific transmembrane transport proteins.

Answer 28

Facilitated Diffusion

Question 29

The movement of a substance across a cell membrane, with an expenditure of energy, against its concentration or electrochemical gradient; mediated by specific transport proteins.

Answer 29

Active Transport

Question 30

The diffusion gradient of an ion, which is affected by both the concentration difference of the ion across a membrane (a chemical force) and the ion’s tendency to move relative to the membrane potent ion (an electrical force).

Answer 30

Electrochemical Gradient

Question 31

An active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process.

Answer 31

Proton Pump

Question 32

Cellular uptake of biological molecules and particulate matter via formation of new vesicles from the plasma membrane.

Answer 32

Endocytosis

Question 33

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Answer 33

Pinocytosis

Question 34

A transmembrane protein channel that opens or closes in response to a particular stimulus.

Answer 34

Gated Channels