homeostasis and cell transport 5.1 passive transport 5.2 active transport
TRANSCRIPT
Homeostasis and Cell Transport
5.1 Passive Transport
5.2 Active Transport
Homeostasis Biological balance with the environment Dynamic Equilibrium
- occurs when the concentration of
molecules of a substance is the same across
a space Works to control what enters and exits the
cell.
Permeability Allowing a substance to pass through
a membrane. Selectively Permeable
- only allowing some substance to pass
through the membrane
- based on size, shape, type
- important in maintaining homeostasis
Passive Transport NO CHEMICAL ENERGY IS USED Spontaneous Examples:
- osmosis- diffusion- facilitated diffusion- gated channels
Diffusion Moving from high concentration to low
concentration Concentration Gradient
- difference in concentrations of a substance across a space Osmosis
- diffusion of water
Example of Diffusion
Example of Osmosis
Hypertonic Solutions Concentration of solute in the
environment is greater than that of the cell
- higher concentration of water inside the cell
- water moves outside of the cell Plasymolysis: plant cells Crenation: animal cells
Hypotonic Solutions Concentration of solute in the environment
is less than that of the cell
- higher concentration of water outside
the cell
- water moves into the cell Cytolysis: animal cell Turgid: plant cell (homeostasis) Contractile Vacuole for protists
Isotonic Solutions Concentration of solutes inside and
outside the cell are equal No net movement of water
Flaccid: plant cells (fatal) Animal cells: homeostasis RBC’s .9% saline
RBC…what type of solution?
RBC…what type of solution?
RBC…what type of solution?
Keep in mind…
Passive Transport (2) Facilitated Diffusion
- use of carrier molecules or transport
proteins
-molecules are too large or not soluble in
lipidsEX. Glucose and Insulin
Ion Channels- protein controlled passage
- solutes enter on an “as needed” basisEX. Nerve Cells
Facilitated Diffusion
Diffusion vs. Facilitated Diffusion
Ion Channel
Active Transport Requires the use of CHEMICAL ENERGY (ATP) Examples:
- Sodium-Potassium Pump- Endocytosis
(pinocytosis and phagocytosis)- Exocytosis
Sodium-Potassium Pump
Occurs in muscle cells
Found in the plasma membrane
3 Sodium (Na+) leave and 2 Potassium (K+) enter AGAINST the concentration gradient
Uses carrier molecules
Sodium-Potassium Pump
Endocytosis Allows large molecules to enter the cell without
passing through the cell membrane
Phagocytosis solid particles Ex. white blood cells
Pinocytosis liquid particles Ex. Electrolytes entering the cell
Endocytosis
Exocytosis Allows large molecules to exit the cell without
passing through the cell membrane
Uses vacuoles and vesicles-proteins made in the ribosomes are
released in this fashion after they travel to the golgi apparatus
-contractile vacuoles
Exocytosis