Chapter 7: Membrane Structure and Function

Question 1

Movement of a substance across a membrane against its concentration or electrochemical gradient, meditated by a specific transport protein and requiring energy

Answer 1

Active Transport

Question 2

Having a hydrophobic and hydrophilic region

Answer 2

Amphipathic

Question 3

A channel protein in a cellular membrane that specifically facilitates osmosis, the diffusion of free water across the membrane

Answer 3

Aquaporin

Question 4

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

Answer 4

Concentration Gradient

Question 5

Coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own gradient

Answer 5

Co-transport

Question 6

Random thermal motion of particles of liquids, gases or solids. The net movement of a substance from a region where it is more concentrated to a region where it is less concentrated. (Electrochemical gradient)

Answer 6

Diffusion

Question 7

Diffusion gradient of an ion, affected by both the concentration gradient of an ion across the membrane and the ion’s tendency to move relative to the membrane potential

Answer 7

Electrochemical Gradient

Question 8

Active transport protein that generates a voltage across membrane while pumping ions

Answer 8

Electrogenic Pump

Question 9

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

Answer 9

Endocytosis

Question 10

Cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane

Answer 10

Exocytosis

Question 11

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

Answer 11

Facilitated Diffusion

Question 12

In a plant cell, lacking turgor in surroundings where there is a tendency for water to leave the cell. a walled cell if it has a higher water potential than its surrounding, resulting in loss of water

Answer 12

Flaccid

Question 13

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

Answer 13

Fluid Mosaic Model

Question 14

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

Answer 14

Gated Channel

Question 15

A lipid with one or more covalently attached carbohydrates

Answer 15

Glycolipid

Question 16

A protein with one or more covalently attached carbohydrates

Answer 16

Glycoprotein

Question 17

A solution, when surrounding a cell, will cause the cell to lose water

Answer 17

Hypertonic

Question 18

A solution, surrounding a cell, will cause the cell to take up water

Answer 18

Hypotonic

Question 19

A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient

Answer 19

Ion Channel

Question 19

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 aqueous solution on one or both sides of the membrane

Answer 19

Intergral Protein

Question 20

A solution, when surrounding a cell, causes no net movement of water into or out of the cell

Answer 20

Isotonic

Question 21

The difference in electrical charge 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 21

Membrane Potential

Question 22

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

Answer 22

Osmoregulation

Question 23

The diffusion of free water across a selectively permeable membrane

Answer 23

Osmosis

Question 24

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

Answer 24

Passive Transport

Question 25

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

Answer 25

Peripheral Protein

Question 26

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 hypotonic environment

Answer 26

Plasmolysis

Question 27

Active transport protein in membrane uses ATP to transport ion out of a cell against their concentration gradient, generating a membrane potential in the process

Answer 27

Proton Pump

Question 28

A property of biological membranes 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

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

In plant cells, a walled cell becomes turgid if it has a lower water potential than its surrounding, resulting in entry of water

Answer 32

Turgid