State that triglycerides are non-polar hydrophobic molecules and describe the molecular structure of triglycerides with reference to fatty acids (saturated and unsaturated), glycerol and the formation of ester bonds

SouravOctober 28, 2024

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Triglycerides are non-polar, hydrophobic molecules, meaning they do not dissolve in water. This property makes them ideal for long-term energy storage in organisms.

Molecular Structure of Triglycerides

1. Glycerol Backbone:
   • A triglyceride molecule consists of a single glycerol molecule, which is a three-carbon alcohol with three hydroxyl (-OH) groups.
2. Fatty Acids:
   • Each of the three hydroxyl groups on the glycerol molecule can form a bond with a fatty acid. Fatty acids are long hydrocarbon chains with a carboxyl (-COOH) group at one end.
   • Saturated Fatty Acids:
     • Saturated fatty acids have no double bonds between the carbon atoms in their hydrocarbon chain, meaning each carbon is fully “saturated” with hydrogen atoms.
     • They tend to have straight chains, allowing them to pack closely together, which makes them solid at room temperature (e.g., in animal fats like butter).
   • Unsaturated Fatty Acids:
     • Unsaturated fatty acids contain one or more double bonds in their carbon chain.
     • The presence of a double bond introduces a kink in the chain, preventing tight packing. As a result, unsaturated fatty acids are often liquid at room temperature (e.g., in plant oils like olive oil).
3. Formation of Ester Bonds:
   • The formation of a triglyceride involves a condensation reaction between each hydroxyl group of glycerol and the carboxyl group of a fatty acid.
   • In this reaction, a molecule of water is released, and an ester bond (-COO-) is formed between the glycerol and each fatty acid.
   • This process is repeated three times, once for each fatty acid, resulting in a triglyceride with three ester bonds.