BIOL 1201 Lecture : Test 2 Lecture Notes
Document Summary
The problem a cell and its environment. The interior of a cell is different than its environment. How to defend the internal environment but still communicate with the external environment: transport materials across the barrier. Amphipathic: hydrophobic (nonpolar) regions, hydrophilic (polar) regions. At the cell/body temperature: similar fluidity in different species, species with a body temperature of 10 c will have fluidity similar to a species with a body temperature of 20 c. Raised pigs wearing underwear in a hot room. Changed the properties of the subcutaneous fats: had a higher melting point. Membrane fluidity adjusted by changing the ratio of unsaturated to saturated fatty acids. Direction of movement: expect down the concentration gradient, against the gradient e. g. sodium 5- 15 mm in the cell; 145 mm outside, how do you move sodium out of the cell, transport processes. Active: against the concentration gradient, requires supplied energy (atp, carrier molecule, work must be done, energy used.
