Unit 4

• Nutritional and Energetic Characteristics of Dietary Fats:
• Caloric Density:
• Fats yield $9\text{ kcal/g}$ ($37\text{ kJ/g}$), over double the energy of carbohydrates and proteins ($4\text{ kcal/g}$).
• Official Answer Key: Designated Option 3 as the target choice.
• Conclusion: Fats are a concern because they have a high caloric density (Option 3).

Correct option: (3) Fats are a concem because they have a high caloric density of

• Number of Chiral Centers in Cholesterol:
• Stereochemistry of Cholesterol ($\text{C}_{27}\text{H}_{46}\text{O}$):
• Contains 8 asymmetric (chiral) carbon atoms:

• 3 (bearing the hydroxyl group)
• 8 (ring B/C junction)
• 9 (ring B/C junction)
• 10 (angular methyl group)
• 13 (angular methyl group)
  6. C-14 (ring C/D junction)
  7. C-17 (attached to side chain)
  8. C-20 (branched aliphatic tail)
  • Gives rise to $2^8 = 256$ theoretical stereoisomers.

• Conclusion: 8 (Option 3).

• Chemical Classification of Vitamin E:
• Chroman Ring Structure:
• Vitamin E (tocopherols and tocotrienols) consists of a substituted chroman (6-chromanol / dihydrobenzopyran) nucleus attached to an isoprenoid hydrophobic hydrocarbon phytyl side chain.
• Acts as a lipid-soluble chain-breaking antioxidant protecting polyunsaturated lipids.
• Conclusion: Vitamin E (Option 3).

Correct option: (3) Vitamin E