Ch. 5-Transport Across Biological Barriers

Question 0

what is the cell membrane considered?

Answer 0

a phospholipid bilayer

-the phospholipids have a hydrophilic head and two hydrophobic tails

Question 1

main hurdle for drugs to cross

Answer 1

cell membrane

Question 2

transmembrane proteins

Answer 2

act as a channel and are on the entire length of membrane

Question 3

peripheral protein

Answer 3

located on edge of membrane

Question 4

functions of cell membrane

Answer 4

• structure (holds cellular contents)
• barrier
• sensitivity (responds to environment)
• regulation (controls what gets in and out)

Question 5

3 components of cell membrane

Answer 5

lipids, proteins, carbohydrates

Question 6

lipids

Answer 6

form the lipid bilayer and only allows substances with lipid solubility to cross

Question 7

proteins

Answer 7

channel proteins, carrier proteins, and receptor proteins

Question 8

carbohydrates

Answer 8

they provide fuel (ATP) for cellular reactions, and they are markers to identify cells

Question 9

3 modes of transport

Answer 9

passive diffusion, carrier-mediated transport, and endo- and exocytosis

Question 10

passive diffusion

Answer 10

drug moves from area of higher concentration to lower concentration

• most common form of transport
• Fick’s law: diffusion is proportional to concentration gradient, diffusion coefficient, and inversely proportional to membrane thickness

Question 11

carrier mediated transport (and 2 types)

Answer 11

membrane protein carries solute across the membrane

• facilitated diffusion
• active transport

Question 12

facilitated diffusion

Answer 12

carrier-mediated version of passive diffusion, requires no energy

Question 13

active transport

Answer 13

requires ATP and moves against the concentration gradient (low to high concentration)

• uniporter (one molecule)
• antiporter (two molecules, opposite directions)
• symporter (two molecules, same direction)

Question 14

endocytosis

Answer 14

vesicle formed for taking something in to the cell

• phagocytosis: engulfing large particle (eating)
• pinocytosis: engulfing fluid and some small particles (drinking)

Question 15

exocytosis

Answer 15

vesicle formed to excrete wastes from cell

Question 16

ion trapping

Answer 16

pH change causes dissociation of acid or base resulting in ionized concentration being higher on one side than the other-ionized solute becomes trapped on receiver side

Question 17

drug efflux

Answer 17

mechanism to pump the drug out of the cell

Question 18

cell junctions

Answer 18

hold cells together to communicate as part of a tissue or organ

• anchoring
• gap
• tight

Question 19

anchoring junction

Answer 19

adhesion, used on tissues subject to constant stress such as the skin and the heart

Question 20

gap junction

Answer 20

communicating, allows substances and chemical information to be transmitted between cells

Question 21

tight junction

Answer 21

seals space between cells to keep substances from going through the intercellular space