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Cellular Transport
I. General A. Definition = molecules moving
across the cell membraneB. Cell Membrane
is selectively permeable(lets some things in,
some things out, but not everything)
1. Passive Transport
a. Requires no energy
b. Caused by random movement of molecules
c. Molecules move with the concentration gradient
c. Examples of Passive Transport
i. Diffusion = process by which
molecules movefrom areas of high concentration
to areas of low concentration
until equilibrium is reached
c. Examples of Passive Transport
ii. Osmosis = diffusion of water
iii. Ion Channels = charged molecules moved across membrane by proteins
c. Examples of Passive Transport
iv. Facilitated Diffusion molecules moved across
membrane by carrier proteins
?s 6-10
2. Active Transport
a. Requires Energy (ATP)
b. Molecules move from areas of low concentration to areas of high concentration
c. Molecules move against the concentration gradient
i. Carrier Protein Pumps
• E.g. Sodium/Potassium Pump- Ion exchange- Na+ moved out / K+ moved in- K+ moved out / Na+ moved in