Chapter 5

Question 0

Aquaporin

Answer 0

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

Question 1

Amphipathic

Answer 1

Having both a hydrophobic and hydrophilic region

Question 2

Active transport

Answer 2

The movement of a substance across a cell membrane against its concentration gradient, mediated by transport proteins that use energy.

Question 3

Concentration gradient

Answer 3

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

Question 4

Cotransport

Answer 4

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

Question 5

Diffusion

Answer 5

The random thermal motion of particles of liquids, gases, or solids. In the presence of a concentration gradient, substances moves from a region of more concentration to lower concentration

Question 6

Electrochemical gradient

Answer 6

The diffusion gradient of an ion, which is affected by both the concentration diffrence of an ion across a membrane and the ions tendency to move relative to the membrane potential

Question 7

Electrogenic pump

Answer 7

An active transport protien that generates voltage across a membrane while pumping ions

Question 8

Endocytosis

Answer 8

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

Question 9

Exocytosis

Answer 9

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

Question 10

Fluid mosaic model

Answer 10

The currently accepted model of the plasma membrane structure, which envisions the membrane as a mosaic of protien molecules drifting latterly in a fluid bilayer of phospholipids

Question 11

Facilitated diffusion

Answer 11

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

Question 12

Glycolipids

Answer 12

A lipid with one or more covalently attached carbohydrates

Question 13

Glycoproteins

Answer 13

A protien with one or more covalent attached carbohydrates

Question 14

Gated channels

Answer 14

A transmembrane protien channel that poems or closes in response to a particular stimulus

Question 15

G protien

Answer 15

A gtp-binding protein that relays signals from a plasma membrane signal receptor

Question 16

G protein coupled receptor

Answer 16

A signal receptor protien in the plasma membrane that responds to the binding of a signaling molecule by activating a g protien

Question 17

Hypertonic

Answer 17

Referring to a solution that, when surround ding a cell, will cause the cell to loose water

Question 18

Hypotonic

Answer 18

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

Question 19

Integral protien

Answer 19

a transmembrane protien with hydrophobic region that extends into and often completely spans the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane

Question 20

Isotonic

Answer 20

Referring to a solution, that, when surrounding s cell, causes net movement of water out of the cell

Question 21

Ion channel

Answer 21

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

Question 22

Ligand

Answer 22

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

Question 23

Ligand gated ion channel

Answer 23

A transmembrane protien containing a Pore that opens of closes as it changes shape in response to a signaling molecule, allowing or blocking the flow of specific ions

Question 24

Membrane potential

Answer 24

The difference in electrical charge across a cells 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.