> Biochemistry : Lipids Quiz
Biochemistry : Lipids Quiz
Lipids are large nonpolar biological molecules that are insoluble in water. Lipids have two major functions: energy storage and make up the structure of cell membranes. Lipids are not polymers; the building blocks of lipids are fatty acids. Fatty acids are long chain carboxylic acids. Most naturally occurring fatty acids have between 12 and 24 carbon atoms. There are two kinds: saturated (which have single covalent bonds) and unsaturated (which have double covalent bonds).
Fatty acids are rarely found alone. They’re usually bonded to glycerol. When three fatty acids are bound to a glycerol backbone though an ester bond, a triglyceride is formed. Triglycerides can be solids or liquids. Solid triglycerides are fats at room temperature and liquid triglycerides are oils at room temperature.
Mixtures of triglycerides from plant sources are liquids because they have unsaturated fatty acids. Animal fats are solids because they have saturated fatty acids.
Fat cells store fatty acids as triglycerides. When energy is needed, cells break down the triglyceride. Phospholipids are triglycerides in which one of the fatty acids is replaced by a polar phosphate group.
Waxes are lipids formed from combining fatty acids with a long chain alcohol. Plants and animals make waxes.
Steroids are lipids with multiple cyclic rings in their structures. Some regulate metabolic processes. Cholesterol is a structural component of cell membranes. Vitamin D plays a role in bone formation.
For the following quiz, review the above summary to assist you in answering the question. Select the best choice from the given answers.
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