Monday, October 17, 2011
Mon-Day 1
AP Chem - Solution Stoichiometry unit exam day; as you saw, the questions were practically the same as those we had done in the notes and homework- these questions test basic professional skills that all chemists must know intuitively. If you were unsure how to do any question, you should study AGAIN tonight, so that you do not repeat such errors. We will finish up the Gas Laws unit this week.
Bio - Today, we discussed the two general types of transport of substances into or out of cells: active transport ( e.g. lower to higher concentration NET movement of a substance; also, phagocytosis, pinocytosis, endocytosis, and exocytosis - examples tomorrow) AND passive transport (e.g. higher to lower concentration NET movement of a substance; diffusion, diffusion-of-water=osmosis, and facilitated diffusion.
We also looked at three examples of osmosis in HYPOtonic (too little solute, HIGHER WATER concentration/percentage) solution, ISOtonic solution, and HYPERtonic (too much solute, LOWER WATER concentration/percentage). We showed that differences in water concentration CAUSED different RATES of water flow into the cell than out of the cell causing the cell to either swell with water (and possible lysis, for animal cells), stay the same, or shrink due to water loss.
The SOLUTE particles/salt ions are NOT generally permeable (CANNOT PASS THROUGH) to cell membranes (phospholipids) other than by ACTIVE TRANSPORT through a specialized TRANSPORT PROTEIN; this is why we had to focus ONLY on the net WATER movement.
Generally, only small molecules (CO2, O2, H2O, amino acids) can get through the pores in the phospholipid bilayer of the cell (plasma) membrane. Glucose is too big too fit through the pores, but it diffuses into or out of a cell with the HELP of a facilitator protein i.e. facilitated diffusion. Starches, proteins, and DNA are generally too big to get into or out of a cell at all, but SOME proteins are actively transported out of a cell after being surrounded by a synthesized plasma membrane made in the Golgi Bodies.
Bio - Today, we discussed the two general types of transport of substances into or out of cells: active transport ( e.g. lower to higher concentration NET movement of a substance; also, phagocytosis, pinocytosis, endocytosis, and exocytosis - examples tomorrow) AND passive transport (e.g. higher to lower concentration NET movement of a substance; diffusion, diffusion-of-water=osmosis, and facilitated diffusion.
We also looked at three examples of osmosis in HYPOtonic (too little solute, HIGHER WATER concentration/percentage) solution, ISOtonic solution, and HYPERtonic (too much solute, LOWER WATER concentration/percentage). We showed that differences in water concentration CAUSED different RATES of water flow into the cell than out of the cell causing the cell to either swell with water (and possible lysis, for animal cells), stay the same, or shrink due to water loss.
The SOLUTE particles/salt ions are NOT generally permeable (CANNOT PASS THROUGH) to cell membranes (phospholipids) other than by ACTIVE TRANSPORT through a specialized TRANSPORT PROTEIN; this is why we had to focus ONLY on the net WATER movement.
Generally, only small molecules (CO2, O2, H2O, amino acids) can get through the pores in the phospholipid bilayer of the cell (plasma) membrane. Glucose is too big too fit through the pores, but it diffuses into or out of a cell with the HELP of a facilitator protein i.e. facilitated diffusion. Starches, proteins, and DNA are generally too big to get into or out of a cell at all, but SOME proteins are actively transported out of a cell after being surrounded by a synthesized plasma membrane made in the Golgi Bodies.
# posted by C @ 3:56 PM 
