cells and transport test Flashcards
cell membrain FUNCTIONS:
- Selectively Permeable or Semipermeable:
Regulates what enters/leaves the cell. - Separates inside cytoplasm from extracellular
(outside) environment. - Receives chemical messengers (hormones,
neurotransmitters, medicines) & passes the info to
the cell so it can respond.
CHOLESTEROL:
Located b/w the fatty
acids to stabilize &
strengthen the flexible cell
membrane.
PHOSPHOLIPID BILAYER:
– Determines what
molecules can enter &
leave the cell based on
their charge & size.
Anchor
Proteins:
keep
cells attached
forming tissues.
Enzymatic
Proteins:
catalyze
METABOLIC
reactions.
- Active site exposed to
substances in cytoplasm.
Identifier (Cell
Recognition) Proteins:
helps immune system
distinguish “self” vs.
foreign.
▪ Have unique carbohydrate
chains attached!
Receptor Proteins:
receive
chemical messengers & pass the
info to the cell so it can RESPOND!
Target Cells:
have specifically
shaped receptor proteins for only
certain chemical messengers.
Hormones &
Neurotransmitters:
types of
chemical messengers that bind
to specific receptors in order to
transmit a message.
Channel Proteins:
provides a
hydrophilic channel so charged
substances can cross the
membrane.
Carrier Proteins:
change shape
while shuttling SPECIFICALLY
SHAPED substances across the
membrane.
Living Cells:
H2O = ~98%
Solutes = 2%
(glucose, salt, O2, CO2
, amino
acids, etc.)
CONCENTRATION GRADIENT:
Difference in
solute [ ]
b/w 2 areas.
EQUILIBRIUM:
Solute & H2O
molecules are
equally
distributed, &
continue moving
evenly in all
directions.
DIFFUSION:
Movement of molecules
from high 🡪 low [ ]
w/out use of ATP
energy (usable energy).
Simple diffusion
through the phospholipids: nonpolar
molecules (small lipids, steroids, gases) can pass b/w the
phospholipids because they can interact with the
nonpolar fatty acid tails!
Facilitated Diffusion
through transport proteins:
charged substances (glucose, H2O, ions, polar molecules)
CANNOT interact w/ nonpolar fatty acid tails, SO they
must diffusion through a transport protein.
WHAT ABOUT LARGE POLYMERS, LIKE
PROTEINS OR POLYSACCHARIDES?
TOO LARGE to diffuse across the membrane…
SO they must be hydrolyzed into monomers & then can
diffuse across the membrane.
OSMOSIS:
PASSIVE TRANSPORT OF
WATER
HYPERTONIC SOLUTION:
solution that has a HIGHER [ ]
of solute.
ISOTONIC SOLUTION:
the solutions outside of cell
and inside the cytoplasm
have an equal solute [ ].