* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Standard B-2
Survey
Document related concepts
Cytoplasmic streaming wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Signal transduction wikipedia , lookup
Cell growth wikipedia , lookup
Cytokinesis wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell membrane wikipedia , lookup
Transcript
Standard B-2 B- 2.5 Explain how active, passive and facilitated transport serve to maintain the homeostasis of the cell. Homeostasis • The necessity of the organism to maintain constant or stable conditions. Examples: #1 -Your body maintains the same body temperature. That is homeostasis. #2- Your body maintains a constant blood sugar level. Normal blood sugar is about 100 mg/ cm3 Cells must maintain homeostasis • Homeostasis of cells depends on appropriate movement of materials across the cell membrane. – Materials needed for cellular processes must pass into cells – Waste materials from cell processes must pass out of cells as they are produced – The cell membrane regulates the passage of material into and out of the cell. Each cell exists in a fluid environment • The cytoplasm within the cell also has a fluid environment. • The liquid environment allows for substances the cell needs to move into the cell • The liquid environment allows for waste products to move out of cell. The cell membrane is semipermeable • Some things can get through • Other substances cannot get through • How do the substances get through? • Passive transport – go through without energy • Active transport- go through with energy Materials pass through by • Passive transport- without energy – From high to low concentration • Or • Active transport – From low to high – Requires energy Passive Transport • Substances pass through membrane without energy • High concentration to low • Diffusion- spreading out of molecules across a cell membrane until they are equal on both sides of the membrane. • Diffusion goes with the concentration gradient • High to low concentration High to low requires no energy- like going down steps Concentration Gradient Diffusion ( passive transport) • Particles of solute move across the membrane from a high concentration gradient to a low concentration gradient. • ( from high to low) • No energy needed • Goes from high to low • Goes without energy. Facilitative diffusion(passive) • Particles move through proteins in cell membranes • No energy used • Particles go from high concentration to low concentration • No energy used Active Transport • Particles go from low concentration to high • Requires energy • It is like stuffing a large sleeping bag into a small bag. • It requires energy • Goes from Low concentration To high Osmosis (passive diffusion of water) • Diffusion of WATER molecules across membrane • From an area of greater water molecules to lesser amount of water molecules • Water molecules will pass through semipermeable membranes until concentration on both sides is the same EQUILIBRIUM- Concentration is equal on both sides Osmosis- Water travels through the membrane until concentration of particles is even on both sides. In Osmosis water will travel across membrane until concentration of solute is even (in equilibrium ) on both sides. Three types of solutions a cell could be in ( Osmotic situations only) • Hypertonic solution- More solute in outer solution than in the cell – Water will leave cell – Cell will shrink • Hypotonic solution- Less solute in outer solution than in the cell – Water will enter cell – Cell will explode (lyse) • Isotonic solution- The solute inside cell is equal to outside cell – Water will pass in and out at equal rates – Cell will stay the same size