Skip to main content
Pearson+ LogoPearson+ Logo
Ch.15 Lipids
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 15, Problem 21

Draw the condensed structural formula for a triacylglycerol that contains stearic acid and glycerol.

Verified step by step guidance
1
Understand the components of a triacylglycerol: A triacylglycerol (also called a triglyceride) is formed by the esterification of three fatty acid molecules with one glycerol molecule. Glycerol is a three-carbon alcohol with hydroxyl (-OH) groups on each carbon, and stearic acid is a saturated fatty acid with the formula CH₃(CH₂)₁₆COOH.
Identify the functional groups involved in the reaction: The hydroxyl (-OH) groups on glycerol will react with the carboxylic acid (-COOH) groups of stearic acid to form ester bonds. This reaction releases water (H₂O) as a byproduct.
Determine the structure of the triacylglycerol: Replace each hydroxyl group on the glycerol molecule with an ester group (-COO-) that is connected to the stearic acid chain. The resulting structure will have three stearic acid chains attached to the glycerol backbone via ester linkages.
Write the condensed structural formula: Start with the glycerol backbone (CH₂, CH, CH₂) and attach the stearic acid chains to each carbon via ester bonds. The condensed formula will look like CH₂(OCO(CH₂)₁₆CH₃)-CH(OCO(CH₂)₁₆CH₃)-CH₂(OCO(CH₂)₁₆CH₃).
Double-check the structure: Ensure that the glycerol backbone is intact, each hydroxyl group has been replaced by an ester linkage, and the stearic acid chains are correctly represented. Verify that the formula reflects the triacylglycerol structure accurately.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Triacylglycerol Structure

Triacylglycerols, also known as triglycerides, are lipids composed of one glycerol molecule esterified to three fatty acids. The glycerol backbone is a three-carbon alcohol, and each carbon is linked to a fatty acid via an ester bond. Understanding this structure is essential for drawing the condensed formula, as it dictates how the fatty acids are attached to the glycerol.
Recommended video:
Guided course
1:52
Triacylglycerols Concept 1

Fatty Acids

Fatty acids are long hydrocarbon chains with a carboxylic acid group at one end. Stearic acid, a saturated fatty acid with 18 carbon atoms, is commonly found in animal fats. Recognizing the structure of stearic acid is crucial for accurately representing it in the triacylglycerol's condensed formula, as it influences the overall properties of the lipid.
Recommended video:
Guided course
2:00
Fatty Acids Concept 1

Condensed Structural Formula

A condensed structural formula provides a simplified representation of a molecule, showing the arrangement of atoms without depicting all bonds explicitly. In the case of triacylglycerols, this format allows for a clear depiction of the glycerol backbone and the attached fatty acids, making it easier to visualize the molecular structure while maintaining clarity and conciseness.
Recommended video:
Guided course
1:53
Condensed Formula Concept 1