SciHawks

Bio 3/6 - we did another example of organelles working together to maintain cellular or an organism's homeostasis. We then discussed the various levels of organization of cells required to keep complex, multi-celled organisms alive; specialized cells in organized collections called tissues, then more complex organs, and even more complex organ systems are needed because different parts of the body are in very different chemical and physical environments. A single-celled organism has only a single local environment, because the cell is so small.
We then began one of the most important parts of this unit: cell transport.
Check out the videos posted on Blackboard that show diffusion, diffusion-of-water=osmosis, "facilitated"=assisted diffusion, and active transport (requires ATP).

AP Chem- we finished the discussion of the gas laws by explaining that adding another gas to a container will increase total pressure but will NOT affect the collision frequency and force (i.e. partial PRESSURE) of the OTHER gas or gases already in there.
We then derived Graham's Law of Effusion/Diffusion by considering the mathematical formula for KINETIC ENERGY. At a given temperature/average kinetic energy, the greater the molecular mass of a molecule, the slower its average velocity, thus the lower its rate of effusion/diffusion. We then applied the formula to compare the relative rates of effusion of two different gases.