Chapter 5 Membrane Structure and Function Vocab

Question 1

Having both a hydrophilic and hydrophobic region

Answer 1

Amphipathic Molecule

Question 2

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

Answer 2

Aquaporin

Question 3

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

Answer 3

Concentration Gradient

Question 4

The random thermal motion of particles of liquids, gases, or solids.

Answer 4

Diffusion

Question 5

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

Answer 5

Endocytosis

Question 6

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

Answer 6

Exocytosis

Question 7

The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins, requiring no energy expenditure.

Answer 7

Facilitated Diffusion

Question 8

Lacking tugor, as in a plant cell in surroundings where there is a tendency for water to leave the cell.

Answer 8

Flaccid

Question 9

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 9

Fluid Mosaic Model

Question 10

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

Answer 10

Gated Channel

Question 11

A lipid with one or more covalently attached carbohydrates

Answer 11

Glycolipid

Question 12

A protein with one or more covalently attached carbs

Answer 12

Glycoprotein

Question 13

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

Answer 13

Hypertonic

Question 14

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

Answer 14

Hypotonic

Question 15

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 one or both sides of the membrane (or lining the channel in the case of a channel protein.)

Answer 15

Integral Protein

Question 16

An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.

Answer 16

Ion channel

Question 17

Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of the cell.

Answer 17

Isotonic

Question 18

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

Answer 18

Ligand

Question 19

The difference in electrical charge (voltage) across a cell’s plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.

Answer 19

Membrane Potential

Question 20

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

Answer 20

Osmoregulation

Question 21

The diffusion of free water molecules across a selectively permeable membrane.

Answer 21

Osmosis

Question 22

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

Answer 22

Passive Transport

Question 23

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

Answer 23

Peripheral Protein

Question 24

A type of endocytosis in which large particular substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells.)

Answer 24

Phagocytosis

Question 25

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

Answer 25

Pinocytosis

Question 26

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 26

Proton Pump

Question 27

The movement of specific molecules into a cell by the inward budding of vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Answer 27

Receptor Mediated Endocytosis

Question 28

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

Answer 28

Selective Permeability

Question 29

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

Answer 29

Sodium Potassium Pump

Question 30

The ability of a solution surrounding a cell to cause that cell to gain or lose water.

Answer 30

Tonicity

Question 31

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

Answer 31

Transport protein

Question 32

Swollen or distended, as in plant cells. (A walled cell becomes turgid if it has a lower water potential that its surroundings, resulting in entry of water.)

Answer 32

Turgid