Carbohydrates: Monosaccharides and Disaccharides

Carbohydrates

• Monosaccharides are the basic unit of carbohydrates, composed of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio.
• They have the general molecular formula (CH2O)n, where n can be 3, 5, or 6.
• Monosaccharides can be classified according to the number of carbon atoms in a molecule:
  • Trioses (n = 3): e.g., glyceraldehyde
  • Pentoses (n = 5): e.g., ribose and deoxyribose
  • Hexoses (n = 6): e.g., fructose, glucose, and galactose

Disaccharides

• Disaccharides are formed when two monosaccharides react through a dehydration/condensation reaction, releasing water and requiring energy.
• A glycosidic bond forms, holding the two monosaccharide units together.

Carbohydrates + Proteins

• Glycated Hemoglobin (HbA1C) is a type of hemoglobin that permanently binds to proteins like hemoglobin after prolonged exposure to elevated blood sugar.
• HbA1C is different from normal hemoglobin (Hb), which transports four oxygen molecules by binding to four iron atoms inside each HEME Group.

Fats

• Saturated fats have a maximum number of hydrogens bonded to the carbons, making them "saturated" with hydrogen atoms.
• Unsaturated fats have carbon-carbon double bonds within the fatty acid chain.
  • Monounsaturated fats have a single double bond.
  • Polyunsaturated fats have multiple double bonds.

Unsaturated Fats: Cis- and Trans-

• Cis-unsaturated fats:
  • Usually naturally occurring
  • Hydrogens are on the same side of the double bond
  • Create a kink, making them more likely to be liquids at room temperature
• Trans-unsaturated fats:
  • Manufactured
  • Hydrogens are on opposite sides of the double bond
  • No kinks, making them more likely to be solid at room temperature
  • Associated with cardiovascular diseases

Cis Unsaturated, Saturated, Trans Unsaturated

• Cis unsaturated fats:
  • Found in almonds, vegetables, fish, and olive oil
  • Raise "good" cholesterol levels
• Saturated fats:
  • Found in beef, butter, pizza, and ice cream
  • Raise "bad" cholesterol levels
• Trans unsaturated fats:
  • Found in cookies, donuts, cakes, and fries
  • Raise "bad" cholesterol levels

Special Case: Phospholipid

• Amphipathic, with a hydrophilic "head" and hydrophobic "tail"
• Joined with a glycerol
• Form bilayers, e.g., cell membrane

Special Case: Cholesterol

• Lipid
• Amphipathic, with hydrophobic and hydrophilic regions

Learn about the basic units of carbohydrates, including monosaccharides and disaccharides, their molecular structure and classification.