Carbohydrates, proteins, lipids and nucleic acids are the major molecules of life.
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Living matter is built mainly from four classes of molecules: carbohydrates, proteins, lipids and nucleic acids. Carbohydrates mainly supply energy and structure, proteins provide catalysis, structure and signalling, lipids store energy and form membranes, and nucleic acids carry hereditary information. Most of these are polymers or assemblies of smaller units, joined by condensation reactions that release water and split again by hydrolysis that adds water. All four classes are built from a small set of elements, mainly carbon, hydrogen, oxygen and nitrogen, arranged into a huge variety of functional molecules. Understanding these classes is the starting point for biochemistry, nutrition and medicine.
Key ideas: The four major classes are carbohydrates, lipids, proteins and nucleic acids. Carbohydrates have the empirical formula Cn(H2O)n, proteins are polymers of amino acids joined by peptide bonds, nucleic acids are polymers of nucleotides, and lipids are defined by solubility rather than a repeating unit. Monomers join by condensation and split by hydrolysis, each releasing or consuming one water.
Common mistakes and connections: Students call lipids polymers, but they are not built from a repeating monomer. Another error is thinking all biomolecules are made only of C, H and O, forgetting N in proteins and nucleic acids and P in nucleic acids and phospholipids. Links to organic functional groups and to metabolism.
Approximate composition of the human body by mass. Besides water and minerals, the bulk is protein, lipid, carbohydrate and nucleic acid biomolecules. The interactive lesson shows this as a live animation or chart.
Bread supplies carbohydrates, beans supply protein, butter supplies fat and every cell nucleus holds DNA.
Carbohydrates, proteins, lipids and nucleic acids are the major molecules of life.
Biomolecules is a beginner topic in Biochemistry, Environment & Industry. It needs no earlier chemistry lessons and is a good starting point.
It is one of the first topics in Biochemistry, Environment & Industry, so no earlier lesson in this area is required.
The next topics in Biochemistry, Environment & Industry are Monosaccharides and Disaccharides.
Yes. The interactive lesson includes a self-check question on Biomolecules, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.
Biomolecules is topic 1 of 127 in Biochemistry, Environment & Industry.
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