File - Life Science | Mrs. Smith
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Transcript File - Life Science | Mrs. Smith
The Gatekeeper of the Cell
The Cell Membrane
Cell Membranes surround all cells
The cell membrane acts as a gate keeper:
Let some things in & keep some things out
Selective Permeability
Selectively permeable- some substances can pass
through the membrane while others cannot.
Permeable- can pass through
Impermeable- can NOT pass through
1.
2.
3.
Osmosis
Diffusion
Active Transport
Cell Transport
Transport
Passive
Transport=
No energy
Diffusion
Active
Transport =
needs energy
Osmosis
Review
How would you describe the cell membrane?
a. Rigid
b. Tough
c. Selectively Permeable
d. Impermeable
Passive vs. Active Transport
The main difference :
Passive Transport does NOT require energy
Active Transport does us ENERGY
Passive Transport: Diffusion
Diffusion: a type of passive transport where molecules
move from high concentration to low concentration.
Diffusion
Things that move through cell by diffusion:
food molecules
oxygen
water
Passive Transport: Osmosis
Osmosis: the process that water moves across a cell
membrane high concentration to low concentration.
Osmosis is the diffusion of water molecules!
Review
When water moves from high to low concentration it
is known as:
a. Diffusion
b. Magic
c. Osmosis
d. Active Transport
Passive Transport Video
Cell Equilibrium
Cells always want to maintain balance!
Sometimes this is bad for the cell
EX: Blood Cells
Active Transport
Uses Energy!!!
Moves molecules in the opposite direction
Like going uphill
Examples:
Transport Proteins
Engulfing
Transport Proteins
Proteins in cell membrane “pick up” molecules and
take them inside the cells using energy.
Engulfing
The cell membrane will surround the molecule and
“swallow” it forming a vacuole.
Review
What is the difference between active and passive
transport?
a. Active transport requires energy
b. Passive transport requires energy
c. Neither require energy
d. Active transport involves osmosis
Active Transport Video