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Objectives
The primary objective of biochemistry is to provide a chemical explanation for the functioning of living cells. However, biochemistry is not an isolated discipline; it encompasses several fields of investigation, including molecular biology, cell biology, microbiology, physiology, and more. It serves as the foundation for understanding life and relies on principles from physical and chemical sciences, demonstrating the uniformity of biochemical processes across different organisms.
Historical Overview
The history of biochemistry is marked by significant milestones, such as Friedrich Wöhler's synthesis of urea in 1828, which challenged the notion of vitalism by demonstrating that organic compounds could be synthesized from inorganic materials. Other notable discoveries include the identification of insulin in the pancreatic islets of Langerhans and the characterization of prions, proteins present in nerve cell membranes.
Classification
Biochemical processes can be broadly categorized into two types: anabolism and catabolism. Anabolism involves the synthesis of complex molecules from simpler ones, such as the conversion of glucose into glycogen, while catabolism entails the breakdown of complex molecules into simpler ones, such as the conversion of glucose into carbon dioxide.
Molecules
Living organisms utilize approximately 25 of the 92 naturally occurring chemical elements, with carbon, hydrogen, nitrogen, and oxygen being the most abundant. These elements have the unique ability to form covalent bonds through the mutual sharing of electrons, resulting in strong and stable molecular structures.
Organic molecules are classified into four main categories: lipids, carbohydrates, proteins, and nucleic acids.
- Lipids: These molecules, commonly known as fats, consist of hydrocarbon structures and are insoluble in water.
-Carbohydrates: Carbohydrates are carbon-based structures containing numerous hydroxyl groups, making them soluble in water. They serve as a significant energy source and structural component in living organisms.
- Proteins: Proteins are large, complex molecules composed of linear polymers called polypeptides, which consist of amino acids. Enzymes, a type of protein, act as biocatalysts and facilitate specific biochemical reactions within cells.
- Nucleic Acids: Nucleic acids, including DNA and RNA, are essential for the storage and transmission of genetic information.
Reactions
Biochemical reactions within living organisms can be classified as exergonic or endergonic, depending on whether they release or require energy, respectively. These reactions are governed by the principles of thermodynamics, with energy being stored in molecules such as ATP, NADPH, and FADH2.
In summary, biochemistry serves as the foundation for understanding the chemical basis of life and is essential for unraveling the complexities of biological systems. By elucidating the molecular mechanisms underlying cellular processes, biochemistry provides valuable insights into disease mechanisms and potential therapeutic targets. A comprehensive understanding of biochemistry is crucial for advancing our knowledge of living organisms and developing innovative solutions to address various health challenges.
Chemistry: The Logic Behind All Biological Phenomena
Biochemistry: A scientific discipline that studies chemical reactions occurring within cells, focusing on molecules of life, and the study of life. It is the investigation of life at the molecular level, aiming to understand the chemical processes underlying life itself.
Objective: Chemical explanation and functioning of living cells.
Biochemistry is not isolated; it covers several fields of investigation (biomolecules, molecular genetics, cell biology, microbiology, physiology, etc.). It is the study of life and relies on physicochemical disciplines. There is a uniformity in biochemistry.
Physical and chemical laws apply to living systems.
History
- Friedrich Wöhler: First synthesis of an organic molecule, creating urea in 1828.
- Insulin: Named after the "islets" of Langerhans in the pancreas.
- Prions: Proteins present at the cell membrane of nerve cells.
Classification
Metabolism: Set of chemical reactions occurring within the cell. We have two types of reactions:
- Synthesis reactions: Glucose synthesized into glycogen = Anabolism
- Degradation reactions: Glucose into CO2 = Catabolism
Molecules
- Virus: Intracellular parasite, impossible to reproduce.
- Life utilizes approximately 25 of the 92 naturally occurring chemical elements. The four most important elements are C, H, N, O, accounting for 96.6%.
- An animal cell contains 99% of its elements.
- These elements have the ability to form covalent bonds: mutual sharing of one or more electrons, known as valence electrons.
- Covalent bonds are strong and solid.
Classification of Organic Molecules
- Lipids
- Fats
- Hydrocarbon structures
- Insoluble in water
- Carbohydrates
- Carbon structures
- Contain many -OH groups
- Soluble: polar structure
- Proteins
- Large complex molecules: linear polymers
- Called polypeptides containing amino acids (AA)
- An amino acid contains:
- A carbon
- A carboxylic acid function
- A hydrogen atom
- A radical -R
- The organism can synthesize only 20 amino acids.
- Enzymes are proteins, acting as biocatalysts. Their names end with -ase and catalyze specific reactions.
Reactions
In living organisms:
- Exergonic reaction: Produces energy.
- Endergonic reaction: Uses energy.
All biological reactions involve thermodynamics.
Energy is also stored in the form of NADPH and FADH2, in addition to ATP.
In conclusion, biochemistry serves as the cornerstone for understanding the chemical intricacies of life. It is indispensable for deciphering the fundamental processes occurring within living organisms and provides valuable insights into various fields of biological sciences. A comprehensive knowledge of biochemistry is essential for addressing numerous challenges in medicine, agriculture, and biotechnology.
References
1. Berg, J. M., Tymoczko, J. L., & Stryer, L. (2002). Biochemistry (5th ed.). W H Freeman.
2. Voet, D., Voet, J. G., & Pratt, C. W. (2012). Fundamentals of biochemistry: life at the molecular level (4th ed.). Wiley.
3. Lehninger, A. L., Nelson, D. L., & Cox, M. M. (2017). Lehninger principles of biochemistry (7th ed.). W.H. Freeman and Company.