Which group of molecules forms the core of all biological membranes?

• A. Proteins
• B. Nucleic acids
• C. Carbohydrates
• D. Phospholipids

Answer: (D)

Verified step by step guidance

1. Understand the structure of biological membranes: Biological membranes are primarily composed of a bilayer of phospholipids, which form the core structure.
2. Learn about phospholipids: Phospholipids are molecules that consist of two fatty acid tails and a phosphate group head. The tails are hydrophobic (water-repelling), while the head is hydrophilic (water-attracting).
3. Explore the arrangement in membranes: In a biological membrane, phospholipids are arranged in a bilayer with the hydrophobic tails facing inward, shielded from water, and the hydrophilic heads facing outward, interacting with the aqueous environment.
4. Recognize the role of phospholipids: This arrangement allows the membrane to be selectively permeable, controlling the movement of substances in and out of cells.
5. Differentiate from other molecules: While proteins, nucleic acids, and carbohydrates are important components of cells, they do not form the core structure of biological membranes like phospholipids do.