01 Structure of Lipids 大学动物营养学课件 英文版.ppt

Lipid Structure and Function Pages 27-36 in textbook Common Physical Properties of Lipids Soluble in non-polar organic solvents Contain C, H, O Sometimes N P Includes fats and oils – mostly triglycerides Fat: solid at room temperature Oil: liquid at room temperature More highly reduced than CHO 2.25x more energy Lipids or Glucose for Energy? Lipids or Glucose for Energy? Energy from Lipids Compared to carbohydrates, fatty acids contain more hydrogen molecules per unit of carbon, thus, they are in a more reduced form Carbohydrates are partially oxidized so they contain less potential energy (H+ and e-) per unit of carbon Functions and Properties Concentrated source of energy (9 kcal/gm) Energy reserve: any excess energy from carbohydrates, proteins and lipids are stored as triglycerides in adipose tissues Provide insulation to the body from cold Maintain body temperature Mechanical insulation Protects vital organs Functions and Properties Electrical insulation Protects nerves, help conduct electro-chemical impulses (myelin sheath) Supply essential fatty acids (EFA) Linoleic acid and linolenic acid Formation of cell membranes Phospholipids, a type of fat necessary for the synthesis of every cell membrane (also glycoproteins and glycolipids) Functions and Properties Synthesis of prostaglandins from fatty acids Hormone-like compounds that modulates many body processes Immune system, nervous systems, and GI secretions Regulatory functions: lower BP, blood clotting, uterine contractions Help transport fat soluble vitamins Palatability and aroma Flavor and taste for some species! The satiety value – help control appetite Fullness; fats are digested slower Regulated through gastric inhibitory protein (GIP) and cholecystokinin (CCK) Physical Traits of Fatty Acids Form membranes, micelles, liposomes Orient at water:oil interface Contain hydrophobic and hydrophilic groups Lipid bilayer for membranes Micelles formed during digestion Physical Traits of Fatty Acids Fa