Cell Physiology
1. Membrane Transport: the movement of substances across the cell ______________________
occurs in multiple ways because the cell membrane is ______________________ _____________________
(some substances can pass through, while others cannot). This is because the phospholipid
bilayer is arranged with _______________________________ (polar) heads facing the
____________________________ and ________________________ fluids and the _________________________
(nonpolar) tails pointed inward, creating a ________________ core. As a result, only substances
that are _____________________ (“fat loving”) can pass through the plasma membrane without
any assistance or energy input.
a. Passive Transport = No __________ required
i. Diffusion = Molecules tend to move from an area of ___________ concentration
to an area of _________ concentration until they are spread out evenly
1. Simple Diffusion will occur across a cell’s plasma membrane if a
molecule both:
a.
is ___________ enough to fit through
b. can pass through the ______________ ______________
2. Facilitated Diffusion will occur if there are ______________ or _____________
proteins in plasma membrane to assist lipophobic molecules to pass
through
a. Example: _____________________ = specific channel proteins to allow
water to pass through plasma membrane
ii. Osmosis = diffusion of _______________
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1. Hypertonic Solution = concentration of solutes outside the cell is
____________________ than the concentration inside the cell  water
______________ the cell  may result in ______________ of the cell
2. Hypotonic Solution = concentration of solutes outside the cell is
_______________ than the concentration inside the cell  water
______________ the cell  may result in ______________________ of the cell
3. Isotonic Solution = concentration of solutes outside the cell is the
_____________ as the concentration inside the cell  water ______________ in
and out of the cell at an ______________ rate  results in _______ ___________
movement of water molecules into/out of the cell
iii. Filtration = ____________ molecules pass through a _______________________
permeable filter; driven by a ___________________ gradient
1. Example: happens in the ________________
2. Active Transport = requires ________
a. Occurs when solutes:
i. are too ____________to pass through plasma membrane
ii. are unable to dissolve in the _____________ core and there are no ______________
proteins
iii. have to move ______________ their concentration gradient
1. Example: ________________________________
3. Vesicular Transport = ______________ transport
a. Exocytosis = large number of molecules _____________ the cell when vesicles ___________
with the plasma membrane to release contents
b. Endocytosis = large number of molecules ______________ the cell when vesicles fuse
with the plasma membrane to ______________ the cell
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