Biological Membranes

Question 1

composed primarily of lipids with some associated proteins and carbs

Answer 1

Plasma Membrane (PM)

Question 2

pass completely through the lipid bilayer

Answer 2

transmembrane proteins

Question 3

associated w/ only interior or exterior surface pm

Answer 3

embedded proteins

Question 4

may be bound through electrostatic interactions with the lipid bilayer

Answer 4

membrane associated (peripheral) proteins

Question 5

proteins that allow cells to recognize each other & contribute to proper cell differentiation and development

Answer 5

Cell Adhesion Molecule (CAM)

Question 6

allow for direct cell-cell communication & are often found in small bunches together; also called connexons (pores composed of 6 molecules of connexin)

Answer 6

gap junctions

Question 7

prevent solutes from leaking into the spaces btw cells via a paracellular route

Answer 7

tight junctions

Question 8

bind adjacent cells by anchoring their cytoskeletons

Answer 8

desmosomes

Question 9

processes that do not require intracellular energy stores but rather utilize the [ ] gradient to supply the energy for particles to move

Answer 9

passive transport

Question 10

substrates move down their concentration gradient directly across the membrane

Answer 10

simple diffusion

Question 11

water will move from a region of lower solute concentration to one of higher solute concentration

Answer 11

osmosis

Question 12

simple diffusion for molecules that are impermeable to the membrane (large, polar, or charged)

Answer 12

facilitated diffusion

Question 13

are only open to one side of the CM at any given point

Answer 13

carriers

Question 14

state in which the carrier is not open to either side of the phospholipid bilayer

Answer 14

occluded state

Question 15

viable transporters for facilitated diffusion, may be in open or closed conformation

Answer 15

channels

Question 16

results in the net movement of a solute against its [ ] gradient

Answer 16

active transport

Question 17

uses ATP or another energy molecule to directly power the transport of molecules across a membrane

Answer 17

Primary Active Transport

Question 18

uses energy released by one particle’s going down its electrochemical gradient to drive a different particle up its gradient

Answer 18

Secondary Active Transport

Question 19

when both particles flow the same direction across the membrane

Answer 19

Symport

Question 20

particles flow in opposite directions

Answer 20

Antiport

Question 21

occurs when the cell membrane invaginates and engulfs material to bring it into the cell

Answer 21

Endocytosis

Question 22

endocytosis of fluids and dissolved particles

Answer 22

pinocytosis

Question 23

ingestion of large solids such as bacteria

Answer 23

phagocytosis

Question 24

occurs when secretory vesicles fuse with the membrane, releasing material from inside the cell to the extracellular environment

Answer 24

exocytosis