Chemistry > Organic Chemistry > Biomolecules
Biomolecules are quintessential compounds integral to various biological functions within living organisms. Under the overarching domain of organic chemistry, biomolecules are primarily categorized into four major classes: carbohydrates, proteins, lipids, and nucleic acids.
Carbohydrates
Carbohydrates are organic molecules composed of carbon (C), hydrogen (H), and oxygen (O), typically with a hydrogen:oxygen ratio of 2:1, resembling that of water (H₂O). Their general formula can often be represented as \( (CH_2O)_n \). Carbohydrates are subdivided into three main types:
1. Monosaccharides: Simple sugars like glucose (C₆H₁₂O₆) and fructose.
2. Disaccharides: Composed of two monosaccharide units, such as sucrose (table sugar).
3. Polysaccharides: Chains of monosaccharides, including starch and glycogen, which serve as energy storage, and cellulose, which provides structural integrity in plants.
Proteins
Proteins are large, complex molecules made up of amino acids, which are organic compounds containing both an amine group (—NH₂) and a carboxyl group (—COOH). There are 20 standard amino acids that polymerize to form polypeptide chains, which then fold into specific three-dimensional structures essential for their function. Proteins play a myriad of roles, including enzymatic catalysis, structural support, transport, and regulatory functions.
The primary structure of a protein is its sequence of amino acids, often represented as:
\[ \text{Primary Structure: } \text{N} - \text{Amino Acid}_1 - \text{Amino Acid}_2 - \ldots - \text{Amino Acid}_n - \text{C} \]
where N and C represent the amino (N-terminus) and carboxyl (C-terminus) ends of the polymer chain.
Lipids
Lipids are a diverse group of hydrophobic or amphiphilic molecules, including fats, oils, phospholipids, and steroids. Their primary functions are to store energy, form the structural components of cell membranes, and serve as signaling molecules.
Triglycerides, a common type of lipid, consist of one glycerol molecule esterified to three fatty acid chains. The structure can be summarized as follows:
\[ \text{Triglyceride: } \text{Glycerol} + 3 \text{Fatty Acids} \]
Nucleic Acids
Nucleic acids, namely DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are polymers of nucleotides. Each nucleotide consists of three components: a nitrogenous base, a pentose sugar, and a phosphate group. DNA contains the genetic blueprint of an organism, stored in sequences of the bases adenine (A), thymine (T), cytosine (C), and guanine (G). RNA, which contains uracil (U) instead of thymine, is pivotal in various roles, including acting as a messenger carrying instructions from DNA for controlling the synthesis of proteins (mRNA), as well as structural and catalytic functions (rRNA and tRNA).
Conclusion
Understanding biomolecules is fundamental to the study of life sciences as they are critical in the myriad processes that sustain life. Their study not only encompasses their structure and function but also extends to their interactions and the mechanisms by which they contribute to the physiology and biochemistry of living organisms.