BIOL 1201 : Biology Test 1 Review Session
Document Summary
The interior of a cell is different than its environment. How to defend the internal environment but still communicate with the: transport materials across the barrier external environment. An optimal intermediate fluidity : do not take fluidity too literally, not too solid, not too fluid, preserves membrane function. Increase in unsaturated fats increases the fluidity of the membrane: unsaturated hydrocarbon tails with kinks double bonds. What must be moved across cell membranes: gases, steroid hormones, water. Expect movement down the concentration gradient. Transport processes movement of molecules across membranes. Active: against concentration gradient, require supplied energy (atp, work must be done, carrier molecule. Passive: down concentration gradient, does not require energy, diffusion simple or facilitated. From regions of high concentration to low concentration regions. When concentrations on both side of a barrier are equal: molecules keep moving, there is no net change in solute concentration. Generate atp(energy current of cell), use oxygen.
