Biochemistry - The Study of Chemical Compounds and Processes in Living Organisms

Biochemistry is a scientific field that focuses on the study of chemical compounds and processes in living organisms. It plays a crucial role in expanding our understanding of biological systems and how they work. Biochemistry finds applications in various fields such as agriculture, medicine (including the pharmaceutical industry), and food industry. Many recent developments in biology, such as genetic engineering, biotechnology, and the molecular approach to genetic diseases, are a result of advancements in biochemistry. Additionally, biochemistry serves as a unifying theme in biology, as it underlies many biochemical processes such as photosynthesis, digestion, respiration, excretion, and muscle contraction, all of which take place within cells.

 

Metabolism - Anabolism and Catabolism

Metabolism refers to the sum of all chemical processes that occur within a cell. It consists of two processes known as anabolism and catabolism. Anabolic reactions are those in which simple substances are combined to form complex substances, requiring energy. On the other hand, catabolic reactions involve the breakdown of complex molecules into simpler ones, releasing energy.

 

Chemical Composition of Cells

Cells, the basic units of life, are composed of various biochemicals that determine their structure and functions. Water, which constitutes around 70% of a typical mammalian cell, is present throughout the cell and plays essential roles such as dissolving, suspending, and ionizing materials, as well as regulating cell temperature. Electrolytes are also present throughout the cell and help establish osmotic gradients, pH, and membrane potential. Proteins, found in membranes, cytoskeleton, ribosomes, and enzymes of the cell, provide structure, strength, contractility, catalytic activity, and buffering capacity. Lipids, located in the membranes of Golgi complex and cell inclusions, serve as reserved energy sources, shape, protect, and insulate cells. Carbohydrates, present in the inclusions of cells, provide fuel for metabolic activities. Nucleic acids, specifically DNA in the nucleus, chromosome, and gene, control cell activity, while RNA in the nucleoplasm and cytoplasm transmits genetic information and transports amino acids. Vitamins and minerals, present as trace elements in the cytoplasm and nucleus, work with enzymes in metabolism, maintain osmotic balance, and add strength to buffering. In the living body, only six bioelements, out of the 16 elements and a few others that occur in particular organisms, constitute 90% of the mass.

 

Relationship between Structure and Function of Molecules

Organic molecules, which form the building blocks of cells, consist of small molecules with carbon chains that make up the backbone, and functional groups attached to the carbon chain that determines their characteristics. Examples of small organic molecules in living things include sugars, fatty acids, amino acids, and nucleosides, which often have one or more functional groups. These small molecules can also be units of large organic molecules, known as macromolecules or polymers, where the small molecules are called monomers. Cells contain four classes of macromolecules, including polysaccharides, lipids, proteins, and nucleic acids, which play diverse roles in cells due to their variety and complexity.