Biochemistry

• The quaternary structure of a protein refers to the arrangement of multiple protein subunits into a larger, functional protein complex.
• Functions of lipids

  • Energy source
  • Energy storage
  • Helps in forming the cell membrane
  • Forms hormones and vitamins in the body
  • Provides insulation (provides/regulates heat)
• The largest amount of energy is stored in the body as fat
• 3 categories of lipids

  • Triglyceride
  • Phospholipids
  • Sterols
• Functions of triglycerides


  • Provides texture
  • Preserves freshness
  • Stores as adipose tissue for energy
  • Responsible for the tenderness of meat
• Lipids contain a lot of calories in small spaces
• Lipids


  A family of biomolecules
• Lipids are soluble in organic solvents and insoluble in water because they are hydrophobic
• Fatty Acids


  Building blocks for triglycerides and phospholipids, composed of a chain of carbons and hydrogens
• High triglycerides are associated with a high risk of heart disease
• Triglycerides are the most common lipids in food and the body, making up 95% of lipids found in food
• Phospholipids

  Hydrophilic on one end and hydrophobic on the other, make up the cell membrane
• Fatty acids have 9 kilocalories per gram of fat and have a higher ratio of carbon and hydrogen compared to oxygen
• Major phospholipid in the cell membrane

  • Lecithin (Phosphatidylcholine)
• Cholesterol is the best-known sterol, found in every cell, and helps body processes
• Functions of fats

  • Source of energy
  • Forms body structures
  • Regulates metabolism
  • Enhances absorption of fat-soluble vitamins
  • Provides insulation
  • Cushions major organs
• Types of fats

  • Saturated Fats
  • Unsaturated Fats
• Types of fats

  • Saturated Fats
  • Unsaturated Fats
• Saturated Fats

  • Usually solid at room temperature
  • Linked with the risk of coronary heart disease
  • Sources include animal products like beef, pork, egg yolk, milk
• Cholesterol is a non-fat substance vital to human metabolism
• Major organs

  • Heart
  • Lungs
  • Liver
  • Kidneys
  • Brain
• Low-Density Lipoprotein


  • Bad Cholesterol
  • Causes blockage in the heart arteries
• Trans fat / trans-unsaturated fat


  • Abbreviated as TFA
  • Hydrogenated unsaturated fats
  • Used by commercial food manufacturers for texture, shelf life, and to prevent rancidity
  • Raises LDL and lowers HDL
• Cholesterol is a precursor to Vitamin D and Bile Acids
• Intake of trans fat and saturated fats correlates with increased risk of Cardiovascular Diseases, Stroke, and Cancer
• Cholesterol is one of the structural parts of the Cell Membrane
• High-Density Lipoprotein


  • Good Cholesterol
  • Absorbs cholesterol in the blood and carries it back to the liver
• High levels of cholesterol can form plaque and clog arteries
• High Blood Cholesterol may cause Coronary Heart Disease as it clogs arteries
• Unsaturated Fats

  • Usually liquid at room temperature
  • Sensitive to heat and light damage
  • Stored in dark bottles and used for cold and short hot preparations
  • Monounsaturated sources: Olive, Peanut, Canola, Rape Seed Oil, Almonds, Avocado
  • Polyunsaturated sources: Sunflower, Soybean, Corn, Fish Oil, Walnuts
• Cholesterol is a precursor to Sex Hormones (Testosterone and Estrogen)
• Recommended intake of cholesterol is 300 mg per day