OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Which atoms are found in lipids?

1. Carbon, Nitrogen and Oxygen

2. Carbon, Hydrogen and Nitrogen

3. Carbon, Hydrogen and Oxygen

4. Hydrogen, Oxygen and Phosphorus

The correct answer is: Carbon, Hydrogen and Oxygen

Lipids are a diverse group of molecules that include fats, oils, and steroids, and their primary components are carbon, hydrogen, and oxygen. These atoms are arranged in various structures, such as fatty acids and glycerol, which are the building blocks of many types of lipids. The presence of carbon is crucial as it forms the backbone of lipid molecules, allowing for a variety of molecular configurations. Hydrogen atoms are also significant because they are bonded to the carbon atoms, influencing the properties and functions of the lipids. Oxygen is found in some lipids, particularly in those that have functional groups or form structures like phospholipids, which contain a phosphate group as well. Although nitrogen and phosphorus are important in certain types of lipids (like phospholipids) and other biochemicals (such as proteins and nucleic acids), they are not fundamental components of all lipids. Therefore, the combination of carbon, hydrogen, and oxygen serves as the defining foundation for lipids in general.