TRANSPORT NOTES
1. Homeostasis –
Process by which organisms maintain a relatively stable internal environment.
Ex. constant body temperature, blood sugar levels, blood pH
2. Molecule movement –
Molecules are in constant motion. Molecules in fluids collide and spread
out randomly.
3. Equilibrium –
State that exists when the concentration of solutes is the same throughout a solution.
solution – a homogenous mixture that consists of a solvent and solutes.
solute – the substance in a solution that gets dissolved.
solvent – the substance in a solution that does the dissolving.
concentration – the amount of solute dissolved in a solution (solute↑, concentration↑)
4. Diffusion –
The movement of molecules from an area of greater concentration to one of
lower concentration. Occurs when there is a concentration gradient
(a difference in concentration between adjacent areas).
5. Osmosis –
The diffusion of water across a selectively permeable membrane.
6. Selectively Permeable – (refers to the cell membrane because)
It regulates what may enter orleave the cell.
7. Hypertonic - Solution outsidethe cell is more concentrated than inside the cell.
Hypotonic- Solution outside the cell is less concentrated than inside the cell.
Isotonic - Solution outside the cell is the same concentration as inside the cell.
8. Plasmolysis –
The shrinking of a cell due to the loss of water.
It occurs in a hypertonic environment.
Cytolysis –
The bursting of a cell due to the intake of excessive amounts of water.
It may occur in a hypotonic environment.
9. Passive Transport–
Movement of substances across cell membrane without using the cell’s energy.
Ex. diffusion, osmosis, facilitated diffusion
10. Carrier Molecules –
Proteins (in the cell membrane) that transportspecific substances across
the cell membrane.
Ex. carrier molecules transport glucose into thecell during facilitated diffusion.
11. Facilitated Diffusion –
Uses carrier molecules to speed up the transport of ions and large
molecules across the cell membrane.
12. Active Transport–
Movement of substances across cell membrane using the cell’s energy.
Ex. endocytosis, exocytosis, sodium-potassium pump
13. Sodium-Potassium pump –
Form of active transport where 3 sodium ions are moved outof the cell and 2 potassium
Ions are pumped into the cell --> against the concentration gradient (requires ATP – accounts for 30% of the energy used by an animal when it is at rest)
14. Endocytosis –
Process by which cells actively engulf large particles and bring them into
the cell. (packaged in vesicles).
Ex. phagocytosis (solids), pinocytosis (liquids)
15. Exocytosis –
Process where large particles are actively passed out of the cell.