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1. 1. Name the three basic parts of a cell and
describe the functions of each.
2. Why do phospholipids organize into a
bilayer – tail-to-tail – in a watery
environment?

2. Hypertonic, isotonic, or hypotonic?
1. What type of fluid might be infused into the
bloodstream of a patient who needs fluid
drawn out from swollen tissues?
2. What type of fluid might be used (carefully)
to rehydrate the tissues of extremely
dehydrated patients?
3. In a U-tube separated by a selectively
permeable membrane, there is .2 M glucose
in Side A, and .4 M glucose in Side B. Side A is
____ compared to Side B, and Side B is ____
compared to Side A.
4. If the membrane in #3 is only permeable to
water, what will happen?

3. Part 2: Membrane Transport

5. IInntteerrssttiittiiaall fflluuiidd:
 Fluid outside cells
 Rich, nutritious “soup” – amino acids, sugars,
fatty acids, vitamins, hormones, salts, wastes
SSeelleeccttiivvee PPeerrmmeeaabbiilliittyy:
 Plasma membrane only allows some substances
to enter cell
 Nutrients in, wastes out
 By ppaassssiivvee or aaccttiivvee transport

6.  No energy (ATP) needed
 Molecules move down ccoonncceennttrraattiioonn ggrraaddiieenntt
from HIGH  LOW concentration
 Types: diffusion, filtration

7.  NNoonnppoollaarr && lliippiidd--ssoolluubbllee
ssuubbssttaanncceess diffuse directly
through lipid bilayer
 Eg. O2, CO2, fat-soluble
vitamins

8.  TTrraannssppoorrtt pprrootteeiinnss (carrier or channel proteins)
assist molecules across membrane
 Eg. glucose, amino acids, H2O, ions

9.  Water-filled channels
 Eg. ions

10.  Binds to molecule,
changes shape, ferries it
across membrane
 Eg. glucose transporter

11.  Diffusion of H2O
 AAqquuaappoorriinnss:: channel proteins for H2O
passage

14.  Ability of solution to change shape or tone of
cells by changing water volume
 IIssoottoonniicc = equal concentration solutes
 HHyyppeerrttoonniicc = higher conc. of solutes
 HHyyppoottoonniicc = lower conc. of solutes

17.  Energy (ATP) is needed!!
 Move molecules aaggaaiinnsstt ccoonncceennttrraattiioonn
ggrraaddiieenntt from LOW  HIGH concentration
 Types: Primary and Secondary

18.  Directly uses AATTPP to
drive transport
 Eg. Ca2+ pump, H+ pump,
Na+-K+ pump

19. SSooddiiuumm--PPoottaassssiiuumm PPuummpp

20.  Move more than 1 substance at a time
 SSyymmppoorrtt: 2 substances moved in same direction
 AAnnttiippoorrtt: 2 substances cross in opposite directions
 Eg. cotransport of sugars, animo acids, ions

22.  Fluid & large particles transported across
membranes in vveessiicclleess (sacs)
 EExxooccyyttoossiiss: “out of cell” – eject substances
 EEnnddooccyyttoossiiss: “within the cell”- ingest
substances

23.  PPhhaaggooccyyttoossiiss: (cell
eating) – engulf large
or solid material
eg. WBC engulf
bacteria

24.  PPiinnooccyyttoossiiss: (cell
drinking) – fluid
w/dissolved
molecules
Eg. intestinal cells

25.  RReecceeppttoorr--mmeeddiiaatteedd
eennddooccyyttoossiiss:
concentrate specific
substances (lliiggaannddss)
that bind to
rreecceeppttoorr pprrootteeiinnss
Eg. insulin, iron,
cholesterol