Homeostasis and Passive Transport
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Homeostasis:
o 3 things that must be maintained - homeostasis – pH, temp, water
regulation, food regulation
The cell membrane is a semi-permeable membrane.
o Semi-permeable: selects what comes in/out of cell
o Function of the cell membrane: protection/doorway/security guard:
regulates what goes in/out of cell
Parts of a Cell Membrane: (Fluid Mosaic Model)
o Phospholipid bilayer: hydrophyllic heads and 2 hydrophobic tails- line
up in two layers
o Steroids: Helps regulate fluidity of the cell membrane
o Proteins:
 Peripheral Protein: Outside surface of membrane
 Integral Protein: go through membrane from one side to another
3 Types: Channels, Pumps, & Receptors
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Diffusion: movement of molecules from an area of high
concentration to low concentrationes ______
require______________.
Concentration gradient: the difference in the concentration of the solute
molecules across a spacehe difference in the concentration of molecules
across a space
Draw diffusion in three stages until it reaches equilibrium:
Types of Passive Transport:
Diffusion : ability for molecules to move across the cell membrane
passively down the concentration gradient.
o EX: Oxygen and Carbon dioxide
Facilitated Diffusion: type of diffusion where large or charged molecules
use a protein to help them move across the membrane.
o EX: Glucose_
OSMOSIS: DIFFUSION OF WATER FROM A HIGH CONCENTRATION OF H2O TO A
LOWER CONCENTRATION
Summary:
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o
Both require : ENERGY (ATP)
o
They both move from
Label the parts of the cell membrane
ID each type of passive transport
Facilitated Diffusion
Osmosis
A.
B.
C.
D.
E.
Phospholipid bilayer
Integral Protein
Peripheral Protein
Hydrophyllic Head
Hydrophobic Tail
Label the parts of the cell membrane
Simple Diffusion
ID each type of passive transport
Label the parts of the cell membrane
ID each type of passive transport