BIOL 110 1st Edition Lecture 13- Membranes are aggregates (= irregular, non-covalent associated) of P-lipids, steroids, and proteins o Not CB polymers o Nonpolar parts associate by the hydrophobic effect TRYGLYCERIDE/PHOSPHOLIPID COMPONENTS - Fatty acids- long C/H chains of CH2 groups with a carboxylic acid group at one end and a CH2 at the other end - Glycerol- short chain of carbon atoms each with an OH/ Hydroxyl/ alcohol group Saturated/ Unsaturated - Saturated- have only carbon single bond long chains fully saturated with hydrogen - Unsaturated have C=C double bonds leads to kinks in chain o Cis- (kinks to same side) and not “trans” (opp. Side) Health Effects- Saturated fatty acids are less healthy than unsaturated o Increase risk of heart disease, diabetes - Healthy cis unsaturated fatty acids o Unsaturated fatty acids consumption leads to more muscle mass, less abdominal and visceral fat - Worst- trans unsaturated o Artificial food additives made by partial hydrogenation of natural cis unsaturated o Partial leaves some double bonds but turns some of the natural cis double bonds into trans o Trans fat originally found useful because it doesn’t spoil Eliminating them could prevent 50 % of heart attacks Fat and Oils - Fatty acids rarely occur separately, most found in triglycerides/ phospholipids o Overall saturation of triglyceride determines liquid or solid at room temperature Saturated pack well together solid ex.) lard Unsaturated don’t pack well together, stay mobile liquid ex.) oils - Very dense form of energy storage for plants and animals o Highly reduced compounds whose energy is released by oxidation o Much energy for its mass (9 keal/gram) - Phospholipids are related to triglycerides- Replace one fatty acid with phosphate - Still ester bonds between glycerol OH and phosphate acid - Fatty acid tails are nonpolar, can be saturated or unsaturated - Structure: o Polar phosphate “head” groups o 2 nonpolar “tails” - P-lipids will have much different function than triglyceride energy storage P- Lipid Function: Forming Bilayers - P-lipids are part polar and part nonpolar - Form bilayers in water with polar head facing water (outside), nonpolar tail interact away from water (interior) Membrane Function - Bilayers are the major component of biological membrane - P-lipid bilayers creates barrier that separates compartments Carbohydrates - “Hydrated Carbon” (CH2O)n - Carb. Monomers are called sugars/simple carbs. N=3-7o When n=6 with 1 or 2 monomers o Monosaccharides (1n=6) : glucose, fructose o Disaccharides (2n=6) : sucrose, lactose - Simple carb function- energy metabolism Complex Carbs: Polymers - Large polymers of glucose: cellulose, starch, glycogeno Formed by eliminating H from one sugar, OH from another. Degydration synthesis - Function: structural, energy
View Full Document