Biological Membrane

Question 1

fluid mosaic model of membrane structure

Answer 1

a model that describes the phospholipid bilayer as fluid and proposes that integral membrane proteins float freely in the lipid bilayer

Question 2

endocytosis

Answer 2

process by which vesicles are internalized from the plasma membrane; often used to absorb or ingest molecular contents into the cell

Question 3

integral membrane protein

Answer 3

protein that is permanently embedded in the cell membrane

Question 4

transmembrane protein

Answer 4

integral membrane protein that spans the entire width of a cell membrane

Question 5

osmosis

Answer 5

diffusion of water across a selectively permeable membrane due to solute differences on either side of the membrane

Question 6

isotonic solutions

Answer 6

solutions separated by a membrane and containing an equal concentration of non-permeating solutes

Question 7

hypotonic solution

Answer 7

solution with a lower concentration of non-permeating solutes than that of the solution on the other side of a membrane

Question 8

hypertonic solution

Answer 8

solution with a higher concentration of non-permeating solutes than that of the solution on the other side of a membrane

Question 9

facilitated diffusion (passive transport)

Answer 9

movement of molecules across a membrane via transport proteins without energy from ATP hydrolysis

Question 10

active transport

Answer 10

movement of molecules across a membrane, typically against a concentration gradient, by transport proteins that require energy from ATP hydrolysis; this energy requirement can be direct (primary active transport) or indirect (secondary active transport)

Question 11

electrochemical gradient

Answer 11

combined electrical and chemical (diffusion) forces acting on an ion between two sides of a cell membrane

Question 12

membrane potential

Answer 12

electrical potential or voltage between the two sides of the plasma membrane

Question 13

aquaporin

Answer 13

transport protein for the facilitated diffusion of water through a cell membrane

Question 14

ion channel

Answer 14

transport protein for the facilitated diffusion of ion(s) through a cell membrane

Question 15

ion pump

Answer 15

protein that moves ion(s) through a cell membrane by primary active transport

Question 16

cotransporter

Answer 16

protein that moves two or more molecules through a cell membrane by secondary active transport