Introduction to Biochemistry

Biochemistry is the application of chemistry to the study of biological processes at the cellular and molecular level.

• It became a distinct discipline around the start of the 20th century through the combination of chemistry, physiology, and biology to explore living systems' chemistry.
• Biochemistry seeks to understand the structure, function, and interactions of biological molecules.
• Examples of biological molecules include proteins, nucleic acids, carbohydrates, and lipids.
• Biochemistry aims to explain biological processes at a molecular level.

Core Concepts

• Biomolecules: The four major classes of organic biomolecules are carbohydrates, lipids (or fats), proteins, and nucleic acids.
• Enzymes: Biological catalysts that speed up chemical reactions in living organisms.
• Metabolism: The sum of all chemical reactions that occur within a cell or organism, providing energy and building blocks for life processes.
• Energy: The capacity to do work, which is essential for metabolic processes.
• Genetic Information: DNA and RNA carry the genetic information that determines the characteristics of an organism and is passed on to offspring.

Biomolecules

• Carbohydrates: Primary source of energy for the body
• They include sugars, starches, and cellulose.
• Monosaccharides (e.g., glucose) are the simplest carbohydrates.
• Disaccharides (e.g., sucrose) consist of two monosaccharides joined together.
• Polysaccharides (e.g., starch, glycogen, cellulose) are complex carbohydrates composed of many monosaccharide units.
• Lipids: Act as structural components of cell membranes, energy storage molecules, and signaling molecules.
• Lipids include Fats, oils, phospholipids, steroids, and waxes
• Fatty acids form building blocks of many lipids
• Saturated fatty acids contain only single bonds, while unsaturated fatty acids contain one or more double bonds.
• Proteins: Perform a wide variety of functions, including catalysis, transport, and structural support.
• Amino acids are the building blocks of proteins.
• A polypeptide is a chain of amino acids linked by peptide bonds.
• Proteins have four levels of structure: primary, secondary, tertiary, and quaternary.
• Nucleic Acids: Store and transmit genetic information.
• DNA and RNA are the two types of nucleic acids.
• Nucleotides are the building blocks of nucleic acids.
• DNA is a double-stranded helix, while RNA is typically single-stranded.

Enzymes

• Biological catalysts that accelerate biochemical reactions by reducing activation energy.
• Enzymes have high specificity for their substrates.
• Activity can be regulated by temperature, pH, and the presence of inhibitors or activators.
• Enzymes are classified into six major classes based on the type of reaction they catalyze: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
• Active site: The region of an enzyme where the substrate binds and catalysis occurs.
• Cofactors and coenzymes: Non-protein molecules that assist enzymes in their catalytic activity.

Metabolism

• Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms.
• Catabolism: The breakdown of complex molecules into simpler ones, releasing energy.
• Example: the breakdown of glucose during cellular respiration.
• Anabolism: The synthesis of complex molecules from simpler ones, requiring energy.
• Example: the synthesis of proteins from amino acids.
• Metabolic pathways: Sequences of chemical reactions that are catalyzed by enzymes, with the product of one reaction serving as the substrate for the next.
• Regulation of Metabolic Pathways: Cells regulate metabolic pathways to maintain homeostasis and respond to changing environmental conditions through feedback inhibition, allosteric regulation, and hormonal control.

Energy

• The capacity to do work, which is essential for metabolic processes.
• ATP (adenosine triphosphate): The primary energy currency of the cell.
• ATP stores energy in the form of phosphate bonds, which can be hydrolyzed to release energy.
• Gibbs Free Energy (ΔG): A thermodynamic property that measures the amount of energy available in a chemical or physical system to do useful work at a constant temperature and pressure.

Genetic Information

• DNA (deoxyribonucleic acid): Carries the genetic information that determines the characteristics of an organism.
• Double-stranded helix composed of nucleotides containing a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine).
• DNA replication: The process of copying DNA, ensuring that each daughter cell receives an identical copy of the genetic material.
• RNA (ribonucleic acid): Plays a role in protein synthesis and gene regulation.
• Typically single-stranded and contains a sugar (ribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or uracil).
• Transcription: The process of synthesizing RNA from a DNA template.
• Translation: The process of synthesizing proteins from an RNA template.
• Central Dogma of Molecular Biology: Describes the flow of genetic information from DNA to RNA to protein.

Biochemical Techniques

• Used to study the structure, function, and interactions of biomolecules.
• Spectrophotometry: Measures the absorption and transmission of light through a solution, used to quantify the concentration of substances.
• Chromatography: Separates molecules based on their physical and chemical properties.
• Liquid chromatography and gas chromatography are common types.
• Electrophoresis: Separates molecules based on their size and charge.
• SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) separates proteins based on their molecular weight.
• Mass Spectrometry: Measures the mass-to-charge ratio of ions, used to identify and quantify molecules.
• X-ray Crystallography: Determines the three-dimensional structure of molecules.
• Nuclear Magnetic Resonance (NMR) Spectroscopy: Provides information about the structure and dynamics of molecules.
• Microscopy: Used to visualize cells and cellular structures.
• Light microscopy and electron microscopy are common types

Applications of Biochemistry

• Medicine:
• Development of new drugs and therapies for diseases.
• Understanding the molecular basis of diseases.
• Diagnostic tests for detecting diseases.
• Agriculture:
• Improving crop yields and nutritional value.
• Developing pest-resistant crops.
• Understanding plant metabolism.
• Biotechnology:
• Production of recombinant proteins and enzymes.
• Genetic engineering and gene therapy.
• Development of biofuels and bioplastics.
• Nutrition:
• Understanding the role of nutrients in human health.
• Developing dietary guidelines.
• Studying the metabolism of food.

Explore biochemistry, applying chemistry to study biological processes at the cellular and molecular levels. Understand the structure, function, and interactions of crucial biomolecules like proteins, nucleic acids, carbohydrates, and lipids. Learn about enzymes, metabolism, and the energetic processes that drive life.