Lipids Flashcards
Elements present in lipids
Carbon, hydrogen and oxygen
Main types of lipids
Triglycerides, phospholipids and sterols
Lipids have less oxygen so….
Are more efficient energy stores than carbohydrates
Triglycerides made up of
3 fatty acids and one glycerol joined by ester bonds between the carboxylic group of the fatty acid and the hydroxyl group on the glycerol.
Oils:
Generally triglycerides with short or unsaturated fatty acids tend to be liquid at room temperature.
Fats:
Made up of triglycerides with longer or saturated fatty acids usually solid at room temperature.
Triglycerides found in plants
Generally unsaturated, used as energy store and waterproofing
Triglycerides found in animals
Generally saturated (although not in fish), useful energy store and insulator, also provide buoyancy for aquatic animals.
Phospholipid structure
Similar structure to triglycerides, where one fatty acid is replaced with a polar hydrophilic phosphate group.
Phospholipid functions
Generally in cell membrane bilayer, also myelin sheath around nerve fibres and as an important component in surfactant which reduces surface tension in lungs.
Sterols structure
Have hydrophilic end with an OH group and a hydrophobic end- hydrocarbons in a characteristic 4 ring structure.
Sterols functions
Many animal hormones are sterols, such as oestrogen and testosterone.
Cholesterol, strengthens cell membranes at high body temperature, raw material for manufacture of vitamin D, steroid hormones and bile.
Triglycerides functions
Long hydrocarbon tail contains lots of chemical energy- excellent energy store
Insoluble in water - does not affect osmosis in cell
Will form droplets in cells
Buoyancy and waterproofing
Production of metabolic water
Protection around organs.
