Membrane Transport & Communication

Question 1

what do membranes do (4)

Answer 1

1)create barriers which:
protect cells from external environment and some internal substances
2)are actively involved in the movement of molecules into and out of cells
3)provide the wiring for electrical signaling
4)provide the site for many signaling processes

Question 2

what is membrane strucutre

Answer 2

phospholipid bilayer
hydrophilic head
hydrophobic tail

Question 3

what is bulk transport used for

Answer 3

transporting macromolecules

Question 4

what is exocytosis

Answer 4

moving out of the cell

Question 5

what is endocytosis

Answer 5

moving into the cell

Question 6

what are the 3 types of endocytosis

Answer 6

receptor-mediated (viruses)
Pinocytosis (drinking fluid)
phagocytosis (eating)

Question 7

what is cellular transport responsible for

Answer 7

movement of smaller number of molecules across the cell membrane

Question 8

what are the 2 energy potentials for cellular transport

Answer 8

concentration gradient
cleavage of ATP high energy phosphate bonds

Question 9

what are the two basic classes of transport

Answer 9

passive transport
active transport

Question 10

what are the 3 types of passive transport

Answer 10

simple diffusion- osmosis
channel mediated diffusion
carrier mediated diffusion

Question 11

what are channel and carrier mediated diffusion commonly referred to

Answer 11

facilitated diffusion

Question 12

what are the 2 types of active transport

Answer 12

primary (1st)- uses ATP
secondary (2nd)- uses concentration gradient

Question 13

explain simple diffusion

Answer 13

molecules pass through cell membrane
typically lipid based and nonpolar

Question 14

explain facilitated diffusion (channel mediated)
and what are the two types of channel mediated diffusion

Answer 14

includes a membrane spanning protein channel
Leak channel
Gated channel

Question 15

explain leak channel

Answer 15

always open typically charged inside molecules of opposite charge pass through

Question 16

explain gated channel

Answer 16

voltage gated: open by electrical signals
ligand gated: open when ligand binds

Question 17

explain carrier mediated

Answer 17

includes a membrane spanning protein
protein actively binds molecules and carriers them down their concentration gradient.
carrier proteins act like enzymes- lock and key

Question 18

Active transport
explain primary

Answer 18

a pump protein is powered by ATP to move molecules against their concentration gradient

Question 19

Active transport
explain secondary

Answer 19

a pump protein is powered by one molecule concentration gradient to move a different molecule against its concentration gradient

Question 20

what are the 2 terms that can describe all active transporters

Answer 20

antiport
symport

Question 21

define antiport

Answer 21

molecules move in opposite direction

Question 22

define symport

Answer 22

molecules move in same direction

Question 23

what are the two ways that cells communicate

Answer 23

electrical or chemical

Question 24

what is an example of chemical signals

Answer 24

circulatory system

Question 25

what is an example of electrical signals

Answer 25

nervous system

Question 26

how does electrical signals work

Answer 26

very quick and targeted response

Question 27

how does chemical signals work

Answer 27

hormonal signals

Question 28

signaling pathways begin with the binding of a what to a receptor

Answer 28

binding of a ligand to a receptor

Question 29

define ligand

Answer 29

a molecule that binds to a receptor

Question 30

define receptor

Answer 30

a protein that binds a ligand and creates a response.