Introduction to Biochemistry: History

What is Biochemistry?

• Biochemistry studies chemical processes in living organisms and the chemistry of living beings
• It integrates biology and chemistry to explore molecular interactions that sustain life

Historical Development

• Biochemistry emerged in the late 18th and early 19th centuries
• The term "Biochemistry" was introduced by German chemist Carl Neuberg in 1903
• Berzilus discovered enzyme catalysis
• Edward Buchner extracted enzymes
• Louis Pasteur discovered fermentation
• Lohmann discovered the role of Creatine PO4 in muscles
• Hans Krebs discovered the TCA cycle
• Banting and Macleod discovered insulin
• Fiske and Subbarow discovered the role of ATPs
• Watson and Crick discovered the double stranded structure of DNA
• Landsteiner discovered protein structure
• Peter Mitchell discovered oxidative phosphorylation
• Nirenberg discovered the genetic code on mRNA
• Paul Berg discovered recombinant DNA technology
• Karry Mullis discovered polymerase chain reaction
• Khorana synthesized genes

Why Study Biochemistry?

• To understand the biomolecules in the human body, including their chemistry, structure, occurrence, location, functions, and roles
• To determine how biomolecules function through isolation and structural elucidation
• To comprehend biochemical processes in living cells at a molecular and sub-cellular level
• To identify disease mechanisms and improve diagnosis

Branches of Biochemistry

• Structural, molecular, metabolic, and clinical biochemistry
• Enzymology
• Pharmaceutical, nutritional, and computational biochemistry
• Environmental and plant biochemistry

Principles of Biochemistry

• A fundamental aspect is the study of cells and their subcellular organelles
• Cells are the organized units of organisms and provide energy
• Biomolecules (proteins, nucleic acids, lipids, and carbohydrates) are structural and functional components of cells

Cells: Prokaryotes vs. Eukaryotes

• Prokaryotic cells are simple, lacking a nucleus or membrane-bound organelles, while eukaryotic cells are complex and contain membrane-bound organelles and a nucleus

Prokaryotes - Key Features

• Features include a nucleoid region for DNA, ribosomes, a peptidoglycan cell wall, binary fission for reproduction, and flagella for movement

Eukaryotes - Key Features

• DNA enclosed in a nucleus
• Presence of organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum
• Capability of sexual (mitosis & meiosis) or asexual reproduction

Cells Categorized by Energy Source

• Phototrophs obtain energy from light
• Chemotrophs obtain energy from chemical compounds

Key Elements of Life

• Pink-colored elements represent the most essential and abundant
• Purple represents essential but less abundant elements
• Dark blue represents trace elements essential for all organisms (more common)
• Light blue represents trace elements essential for all organisms (less common)

Key Elements

• Carbon (C): Atomic number 6, mass number 12, forms strong bonds and chains
• Hydrogen (H): Abundant, found in organic molecules, and vital for pH balance
• Oxygen (O): Found in monosaccharides, proteins, lipids, nucleotides, and vitamins, and in water
• Nitrogen (N): Forms strong bonds within itself, is in amino acids, and forms single, double, and triple bonds
• Phosphorus (P): Found in DNA, RNA, and ATP and vital for energy storage
• Sulfur (S): Found in amino acids and coenzymes and is key for protein folding/stability

Trace Elements in the Body

• Calcium aids bone formation and muscle contraction
• Potassium enables nerve impulses and enzyme activation
• Magnesium acts as an enzyme cofactor in photosynthesis
• Iron helps blood transport oxygen
• Zinc supports enzyme function and the immune system
• Sodium helps with nerve signaling and fluid balance
• Chlorine maintains fluid balance and digestion

Biomolecules

• Biomolecules are essential organic compounds produced by living organisms whose functional groups dictate their chemical properties
• Water dissolves biomolecules, facilitates transport, promotes reactions, and enables hydrolysis and condensation
• Nucleic acids store, transmit, and express genetic information
• DNA stores genetic information; RNA helps in protein synthesis and cellular processes
• Amino acids are the fundamental units of proteins essential to cell signaling, enzyme function, metabolism, and genetic expression
• Proteins, made from amino acids, support cell signaling and enzymatic activity

Enzymes

• Enzymes act as catalysts in biological processes
• Several biochemical reactions occur with enzyme activity

Carbohydrates

• Carbohydrates contain carbon, hydrogen, and oxygen and consist of monomers called monosaccharides
• Monosaccharides are one monomer unit and include fructose, glucose, and galactose
• Disaccharides are two monosaccharide units and include lactose, maltose, and sucrose
• Polysaccharides are many monosaccharide units and include cellulose, glycogen, and starch
• Glucose is the primary fuel for respiration
• Glycogen and starch store fuel
• Cellulose and chitin provide structural support
• Glycoproteins and glycolipids aid cell communication

Lipids

• Lipids are diverse, hydrophobic biomolecules that store energy, compose cell membranes, and help with cell signaling
• Fatty acids are hydrocarbon chains with a carboxyl group
• Triglycerides store long-term energy in adipose tissue
• Phospholipids are cell membrane components
• Steroids regulate processes and maintain fluidity

Lipid Functions

• Fats store energy
• Phospholipids compose biological membranes
• Fat deposits help maintain body temperature
• Hormones regulate biological processes
• Waxes prevent water loss

Metabolism

• Metabolism describes cellular activities that include capturing energy, converting molecules, polymerizing precursors, and synthesizing/degrading biomolecules
• Catabolism is the degradative phase where molecules convert to simpler products.
• Anabolism builds up larger and more complex molecules
• Amphibolic represents both catabolic, and anabolic reactions