Carbohydrates are the simplest biomolecules, serving as the primary fuel source for cells. They're constructed from simple sugar units called monosaccharides, with a basic formula of (CH2O)x. These monosaccharides can link together to form more complex carbohydrates. Disaccharides like sucrose (table sugar) involve two monosaccharides connected by a dehydration reaction. Polysaccharides, such as starch, cellulose, and glycogen, are long chains of monosaccharides that serve for energy storage or structural purposes.

Lipids are a varied group of biomolecules characterized by their nonpolar nature, meaning they repel water. Their basic building blocks include fatty acids, glycerol, and phosphate groups. Fats and oils, like triglycerides, consist of three fatty acids linked to a glycerol molecule. Steroids, such as cholesterol, have a unique four-ringed carbon structure and play essential roles in cell membranes and hormone production. Phospholipids, with a hydrophilic head and a hydrophobic tail, are major components of cell membranes due to their ability to form bilayers. 

Nucleic acids hold the blueprints for life, storing and transmitting genetic information. They are built from nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. DNA, the genetic material, is double-stranded with a famous double helix structure. The sugar in DNA is deoxyribose, and the nitrogenous bases include adenine (A), guanine (G), cytosine (C), and thymine (T). RNA, another nucleic acid, is single-stranded with the sugar ribose and uses uracil (U) instead of thymine. 

Structure of nucleotides

Structures of Nitrogenous bases

Proteins are the most intricate biomolecules, responsible for a vast array of cellular functions. They are constructed from amino acids linked by peptide bonds. There are 20 different amino acids, and the specific sequence determines a protein's unique structure and function. This structure has four levels: primary (amino acid sequence), secondary (local folding patterns), tertiary (3D folding), and quaternary (arrangement of multiple protein chains). The complex structures of proteins allow them to perform various tasks, from catalyzing reactions to providing structural support.