Chapter 5 (Membrane Structure And Funciton) Vocab Quiz

Question 1

Amphipathic molecule

Answer 1

A molecule having both hydrophilic and hydrophobic regions

Question 2

Aquaporin

Answer 2

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

Question 3

COncentration gradient

Answer 3

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

Question 4

Diffusion

Answer 4

The random thermal motion of particles of liquids, gases or solids. In the resented of a concentration or electrochemical gradient, diffusion results in the net movement of a substance from a region where it is less concentrated.

Question 5

Endocytosis

Answer 5

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

Question 6

Exocytosis

Answer 6

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

Question 7

Facilitated diffusion

Answer 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.

Question 8

Flaccid

Answer 8

Limp, lacking turbot, as in a plant cell in surroundings where there is a tendency for water to leave the cell

Question 9

Fluid mosaic model

Answer 9

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

Question 10

Gated channel

Answer 10

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

Question 11

Glycolipid

Answer 11

A lipid with one or more covalently attached carbohydrates

Question 12

Glycoprotein

Answer 12

A protein with one or more covalently attached carbohydrates

Question 13

Hypertonic

Answer 13

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

Question 14

Hypotonic

Answer 14

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

Question 15

Integral protein

Answer 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 Aquaeous solution on one or both sides of the membrane

Question 16

Ion channel

Answer 16

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

Question 17

Isotonic

Answer 17

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

Question 18

Ligand

Answer 18

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

Question 19

Membrane potential;

Answer 19

The difference in electrical charge across a cells plasma membrane die to the differential distribution of ions membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances

Question 20

Osmoregulation

Answer 20

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

Question 21

Osmosis

Answer 21

The diffusion of free water molecules across a selectively permeable membrane

Question 22

Passive transport

Answer 22

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

Question 23

Peripheral protein

Answer 23

A protein loosely bound to the surface of a membrane or to part of an intergalactic protein and not embedded in the lipid belayer

Question 24

Phagocytosis

Answer 24

A type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals

Question 25

Pinocytosis

Answer 25

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

Question 26

Plasmolysis

Answer 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 hypertonic environment

Question 27

Proton pump

Answer 27

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

Question 28

Receptor mediated endocytosis

Answer 28

The movement of specific olecules 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

Question 29

Selective permeability

Answer 29

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

Question 30

Sodium potassium pump

Answer 30

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

Question 31

Tonicity

Answer 31

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

Question 32

Transport protein

Answer 32

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

Question 33

Turgid

Answer 33

Swollen or distended as in plant cells