Lipid solid at room temperature is called a ...

Lipid solid at room temperature is called a ...

• A. Oil
• B. Fat
• C. Waxes
• D. Phospholipid

Answer: (B)

The state of a lipid at room temperature depends on the saturation of its fatty acids. Fats are solid because they are mainly saturated triglycerides; the straight chains of saturated fatty acids pack closely together, forming a dense, firm material. Oils, in contrast, have many unsaturated fatty acids with kinks from double bonds, which prevents tight packing and keeps them liquid. Waxes are also solids but are a different type of lipid (esters of long-chain alcohols with fatty acids) and aren’t described simply as fats. Phospholipids are membrane components with a glycerol backbone, two fatty acids, and a phosphate group, and they’re not classified by being solid at room temperature like fats. So the lipid that is solid at room temperature is a fat.

The state of a lipid at room temperature depends on the saturation of its fatty acids. Fats are solid because they are mainly saturated triglycerides; the straight chains of saturated fatty acids pack closely together, forming a dense, firm material. Oils, in contrast, have many unsaturated fatty acids with kinks from double bonds, which prevents tight packing and keeps them liquid. Waxes are also solids but are a different type of lipid (esters of long-chain alcohols with fatty acids) and aren’t described simply as fats. Phospholipids are membrane components with a glycerol backbone, two fatty acids, and a phosphate group, and they’re not classified by being solid at room temperature like fats. So the lipid that is solid at room temperature is a fat.