Topic 3: Cellular Transport

Lipids
-made mostly from carbon and hydrogen atoms
commonly found as fats, oils, and waxes
aka fat
Phospholipid
-surround a cell, consist of a “head” and “Tail”
-like to line up into two parallel layers and surround a cell membrane its critical to a cells ability to function
Diffusion
Movement of particles is random but..
-from a high to low concentration
-A passive Process-The cell dos not use energy
-works well over short distances
-Temperature Dependent
Selectively Permeable Membrane
-is one that allows certain molecules or ions to pass through it by means of active or passive transport
-the membrane can also block the passage of materials depending on the conditions inside or outside of the cell.
Small and No Charge
The membrane lets these kind of molecules pass through easily
Large and Charged
the membrane does not let these kinds of ions pass through easily
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Osmosis
the diffusion of water through a selectively permeable membrane
Isotonic
Concentration of solutes-same as cell
Water moves in and out of cell
Cells like isotonic environment 🙂
Hypertonic
Concentration of solutes-more than the cell
water moves out of cell
cell does not like-it shrivels up
Hypotonic
Concentration of solutes-less than the cell
Water moves into the cell
Cell will swell up
Three types of passive transport
-Diffusion
-Osmosis
-Facilitated Diffusion
Facilitated Diffusion
-Fast
-Specific
-a net movement of molecules across a cell membrane
-molecules that cannot diffuse across the cell membrane’s lipid bilayer on their own move through protein channels instead
Active Transport
transport of small molecules or ions across a cell membrane generally carried out by proteins or “pumps” found in the membrane itself
3 types of active transport
-Exocytosis
-Endocytosis
-Pumps/Protiens
Endocytosis
process of taking material into the cell by means of inholdings, or pockets, of the cell membrane
Exocytosis
process of the membrane surrounding the material fuses with the cell membrane forcing contents out of the cell
Passive Transport
does not require the cell to expend any energy and involves a substance diffusing down its concentration gradient across a membrane