Which of the following correctly identifies the three main components of a phospholipid molecule?

• A. Glycerol backbone, three fatty acid tails, and a methyl group
• B. Deoxyribose sugar, fatty acid tail, and amino group
• C. Ribose sugar, nitrogenous base, and phosphate group
• D. Glycerol backbone, two fatty acid tails, and a phosphate group

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the structure of a phospholipid molecule. A phospholipid is a type of lipid molecule that is a major component of cell membranes. It is amphipathic, meaning it has both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.
2. Step 2: Break down the components of a phospholipid. A phospholipid consists of three main parts: a glycerol backbone, two fatty acid tails, and a phosphate group. The glycerol backbone is a three-carbon molecule that serves as the foundation of the phospholipid.
3. Step 3: Analyze the hydrophobic and hydrophilic regions. The two fatty acid tails are hydrophobic and nonpolar, meaning they repel water. These tails are attached to two of the carbons in the glycerol backbone. The phosphate group, attached to the third carbon of the glycerol, is hydrophilic and polar, meaning it attracts water.
4. Step 4: Compare the options provided in the question. Eliminate incorrect options by identifying components that do not match the structure of a phospholipid. For example, options mentioning three fatty acid tails or sugars like ribose or deoxyribose are incorrect because they do not align with the structure of a phospholipid.
5. Step 5: Confirm the correct answer. The correct identification of the three main components of a phospholipid molecule is: glycerol backbone, two fatty acid tails, and a phosphate group.