Homeostasis and Cell Transport

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

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

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

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

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

Types of Diffusion Facilitated Diffusion Facilitated Diffusion “diffusion of molecules across the cell membrane with the help of a carrier protein” “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 Osmosis – the process by which WATER MOLECULES diffuse across a selectively permeable membrane

Direction of Osmosis Direction of Osmosis 1. Hypotonic Solution 1. Hypotonic Solution a. solute is less on the outside of cell compared to the inside a. solute is less on the outside of cell compared to the inside b. water is greater on the outside 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 a. solute is more on the outside than the inside b. water is less 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 a. everything is equal b. homeostasis b. homeostasis

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

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

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

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

Plasmolysis Plasmolysis  hypertonic environment  hypertonic environment  cell shrinks due to water leaving  cell shrinks due to water leaving

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

ATP ATP – Adenosine TriphosPhate ATP – Adenosine TriphosPhate * source of energy * source of energy * used to aid in active transport * used to aid in active transport

ADP ADP – Adenosine DiphosPhate ADP – Adenosine DiphosPhate * when ATP has lost 1 phosphate * when ATP has lost 1 phosphate * energy is released when forming ADP * energy is released when forming ADP

ATP-ADP Cylce

Active Transport Movement of molecules from an area of LOW concentration to HIGH concentration Movement of molecules from an area of LOW concentration to HIGH concentration Down and against the concentration gradient Down and against the concentration gradient Uses ATP to power it Uses ATP to power it

Types of Active Transport Endocytosis Endocytosis * large molecules are taken into the cell * large molecules are taken into the cell * 2 types * 2 types - phagocytosis - phagocytosis - pinocytosis - pinocytosis

Exocytosis Exocytosis * getting rid of large materials in the cell * getting rid of large materials in the cell Endocytosis and Exocytosis Animation Endocytosis and Exocytosis Animation

Na-K Pump Na-K Pump * used to carry nerve signals in the cell * used to carry nerve signals in the cell Animation: How the Sodium Potassium Pump Works Animation: How the Sodium Potassium Pump Works