Which of the following is NOT a major class of lipids found in biological membranes?

• A. Triglycerides
• B. Nucleotides
• C. Phospholipids
• D. Steroids

Answer: (B)

Verified step by step guidance

1. Understand the question: The problem is asking which of the listed options is NOT a major class of lipids found in biological membranes. This requires knowledge of the types of lipids that are typically present in membranes.
2. Recall the major classes of lipids in biological membranes: The primary lipid components of membranes are phospholipids, glycolipids, and cholesterol (a type of steroid). These lipids contribute to the structural and functional properties of membranes.
3. Analyze the options: Triglycerides, phospholipids, steroids, and nucleotides are listed. Triglycerides are storage lipids and not typically found in membranes. Phospholipids and steroids (e.g., cholesterol) are integral to membrane structure. Nucleotides, however, are not lipids at all; they are the building blocks of nucleic acids like DNA and RNA.
4. Identify the outlier: Since nucleotides are not lipids and do not play a role in membrane structure, they are the correct answer to the question.
5. Conclude: The correct answer is 'Nucleotides,' as they are not a class of lipids and are unrelated to biological membrane composition.