Which group includes fats that are long chains of carbon and hydrogen?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Nucleic Acids

Answer: (B)

Fats are a type of lipid, and lipids are built from long hydrocarbon chains made of carbon and hydrogen. In fats, these long chains are attached to a glycerol backbone as fatty acid tails, giving the molecule a highly nonpolar, water-repellent character. This structure lets fats store a lot of energy in a compact form. Carbohydrates are made from sugar units and are generally polar and water-soluble, with energies released more quickly. Proteins are made from amino acids containing nitrogen and form diverse shapes for function. Nucleic acids are built from nucleotides and store genetic information, with a sugar–phosphate backbone rather than long hydrocarbon chains.