Biomolecules: Carbohydrates, Proteins, Nucleic Acids, Lipids

Biomolecules

• Biomolecules are essential organic molecules involved in maintaining and metabolic processes of living organisms.
• They range from small molecules like primary and secondary metabolites and hormones to large macromolecules like proteins, nucleic acids, carbohydrates, lipids, etc.

Carbohydrates

• Carbohydrates are chemically defined as polyhydroxy aldehydes or ketones or compounds that produce them on hydrolysis.
• They are collectively called saccharides, and are often referred to as sugars or sweet-tasting substances.
• Carbohydrates are classified as monosaccharides (1 unit), oligosaccharides (2-10 units), and polysaccharides (more than 10 units) depending on the number of constituting sugar units obtained upon hydrolysis.
• They serve as a major dietary source of energy and have structural importance in many living organisms.

Proteins

• Proteins are polymers of amino acids arranged in the form of polypeptide chains.
• Protein structure is classified as primary, secondary, tertiary, and quaternary, based on the level of complexity of the folding of a polypeptide chain.
• Proteins play both structural and dynamic roles, with examples including myosin, which enables muscle contraction, and enzymes, which are mostly proteinaceous.

Nucleic Acids

• Nucleic acids refer to the genetic material found in cells that carries hereditary information from parents to progeny.
• There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
• The main function of nucleic acids is to transfer genetic information and synthesize proteins through transcription and translation.
• The monomeric unit of nucleic acids is the nucleotide, composed of a nitrogenous base, pentose sugar, and phosphate.
• There are four major nitrogenous bases found in DNA: adenine, guanine, cytosine, and thymine, with uracil replacing thymine in RNA.
• The DNA structure is described as a double-helix or double-helical structure formed by hydrogen bonding between the bases of two antiparallel polynucleotide chains.

Lipids

• Lipids are organic substances that are insoluble in water, soluble in organic solvents, and are related to fatty acids.
• They are utilized by living cells and include fats, waxes, sterols, fat-soluble vitamins, mono-, di-, or triglycerides, phospholipids, etc.
• Unlike carbohydrates, proteins, and nucleic acids, lipids are not polymeric molecules.
• Lipids play a crucial role in cellular structure and serve as a chief source of energy.