Passive Transport

Homeostasis “biological balance between a cell or organism and it’s external environment” Maintained by the cell controlling what enters and exits (plasma cell membrane)

Good Stuff a. CHO e. Water b. Lipids f. Various Chemicals c. Proteins d. Nucleic Acid Bad Stuff a. Waste b. Extra Water

Ways a cell maintain homeostasis 1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Gated Channels 5. Active Transport 6. Endocytosis 7. Exocytosis

Diffusion “movement of molecules from area of HIGH concentration to LOW concentration” Concentration Gradient – difference in concentration

Equilibrium – point where the. concentration of a substance Equilibrium – point where the concentration of a substance is equal throughout the solution

Types of Diffusion Facilitated Diffusion “diffusion of molecules across the cell membrane with the help of a carrier protein”

Osmosis Osmosis – the process by which WATER MOLECULES diffuse across a selectively permeable membrane

Direction of Osmosis 1. Hypotonic Solution a. solute is less on the outside of cell compared to the inside b. water is greater on the outside compared to the inside CELL SWELLS

2. Hypertonic Solution a. solute is more on the outside than the inside b. water is less on the outside than the inside CELL SHRINKS

3. Isotonic Solution a. everything is equal b. homeostasis

Examples Hypotonic Solution * Jellyfish in Lake Norman → Cell swells, fish dies

Hypertonic Solution * freshwater plant in a salt water solution → Plant shrinks/shrivels and dies

Equilibrium/Homeostasis!!! Isotonic Solution * Jellyfish in the Atlantic Ocean Equilibrium/Homeostasis!!!

Roles of Osmosis Kidneys use it to maintain water levels in the blood Turgor Pressure → water pressure in plant cells → hypotonic environment

Plasmolysis → hypertonic environment → cell shrinks due to water leaving

Cytolysis → hyptonic environment → cell bursts due to water rushing into the cell