SBI3C
Transport Across a Cell Membrane (1.14 & 1.16)
Passive Transport
Cell membranes are ____________________ permeable, which means that only certain substances
can pass through them.
Substances that pass through the membrane
freely (directly through the membrane or through
protein channels):
small, uncharged substances such as water,
Substances that cannot pass through the
membrane freely:
oxygen, and ____________________
____________________
small lipid molecules
large molecules
molecules with a positive or negative
____________________ diffusion is the movement of particles from an area where they are highly
concentrated, to an area where they are less highly concentrated (down the concentration
____________________). It requires no energy, and continues until ____________________ is
reached.
____________________ diffusion is passive diffusion through a membrane, assisted by proteins.
-glucose, sodium ions, and chloride ions all move across cell membranes through
facilitated diffusion
Membrane proteins:
- ____________________ proteins span the entire thickness of the cell membrane; some
act as ____________________ proteins (they assist substances to move through)
____________________ is the diffusion of water molecules across a selectively permeable
membrane. Water moves from an area of low solute concentration to an area of
____________________ solute concentration.
When comparing the solute concentration of two solutions, there are 3 terms that are used:
-____________________ solutions have equal solute concentration
-a ____________________ solution has higher solute concentration than another solution
-a ____________________ solution has lower solute concentration than another solution
Active Transport & Bulk Transport
In order to move substances against the concentration gradient, energy is required. A compound
called adenosine triposphate (________) provides the energy for this process.
(Image from: http://avonapbio.pbworks.com/w/page/9429326/Chapter%208)
____________________ transport is the movement of substances through a membrane, against the
concentration gradient, using membrane-bound carrier proteins, and energy from ATP.
____________________ transport also requires energy, and is responsible for moving large
quantities of materials across the cell membrane.
-____________________ is used to bring large amounts of substances into a cell
-____________________ moves solids into the cell
-____________________ moves liquids into the cell
-____________________ is used to take large amounts of substances out of a cell.
(Image from: http://www.anselm.edu/homepage/jpitocch/genbio/cellnot.html)