MCB 150 Lecture Notes - Lecture 4: Membrane Fluidity, Biological Membrane, Catabolism
5 Jun 2019
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If it was static, half of the cell would be dyed red and half of the cell would be green. Since it is fluid, you see a mixing of the two colors. As the hydrocarbon tails become colder, they move slower and flex less, which means they interact with their neighbors more. Hydrocarbons become more tightly packed as they become colder. Gel phase - when the layer solidifies and is incapable of moving molecules across. Fluid phase - no membrane because there is no interaction with neighbors and each lipid acts as an independent unit. The transition from fluid to gel phase (and vice versa) is influenced by the lipid composition of the membrane. The cell can regulate membrane fluidity by changing: The number of cholesterol molecules (at low temperatures) Metabolism is the sum of all chemical activity in the cell--thousands of individual reactions. Catabolism takes molecules (food) and breaks them down. Final products used as precursors for new molecules.
