Graduate
  1. Physical Chemistry  1.1. Thermodynamics  1.1.1. Laws of Thermodynamics  1.1.2. Enthalpy and heat capacity  1.1.3. Entropy and free energy  1.1.4. Phase Equilibrium  1.1.5. Statistical thermodynamics  1.1.6. Thermodynamic cycle  1.1.7. Fugacity and activity  1.2. Quantum Chemistry  1.2.1. Principles of quantum mechanics  1.2.2. Schrödinger Equation  1.2.3. Particle in a box  1.2.4. Operators and eigenvalues  1.2.5. Atomic orbitals  1.2.6. Molecular orbital theory  1.2.7. Perturbation theory  1.2.8. Valence bond theory  1.2.9. Hybridization and chemical bonding  1.3. Chemical kinetics  1.3.1. Rate laws and reaction mechanisms  1.3.2. Collision theory  1.3.3. Transition state theory  1.3.4. Enzyme Kinetics  1.3.5. Chain Reactions and Polymerization  1.3.6. Photochemical reactions  1.4. Statistical mechanics  1.4.1. Partitioning functions  1.4.2. Molecular distribution functions  1.4.3. Boltzmann Distribution  1.4.4. Bose–Einstein and Fermi–Dirac statistics  1.5. Spectroscopy  1.5.1. Rotational Spectroscopy  1.5.2. Vibrational Spectroscopy  1.5.3. Electronic Spectroscopy  1.5.4. Nuclear magnetic resonance spectroscopy  1.5.5. Mass Spectrometry  1.5.6. Raman Spectroscopy  1.5.7. Electron paramagnetic resonance spectroscopy  1.6. Surface and colloidal chemistry  1.6.1. Absorption isotherm  1.6.2. Surface tension and wetting  1.6.3. Colloidal Stability  1.6.4. Catalysis  1.6.5. Emulsions and micelles  1.7. Electrochemistry  1.7.1. Nernst equation  1.7.2. Electrochemical cells  1.7.3. Conductivity and mobility  1.7.4. War  1.7.5. Fuel cells  1.7.6. Electrolysis
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic reactions  2.2. Spectroscopy and structural determination  2.2.1. UV-Vis Spectroscopy  2.2.2. IR Spectroscopy  2.2.3. NMR Spectroscopy  2.2.4. Mass Spectrometry  2.2.5. X-ray crystallography  2.3. Stereoscopic  2.3.1. Chirality and optical activity  2.3.2. Structural analysis  2.3.3. Geometrical isomerism  2.3.4. Dynamic Stereochemistry  2.4. Organometallic Chemistry  2.4.1. Organolithium and organomagnesium reagents  2.4.2. Palladium-catalyzed cross-coupling reactions  2.4.3. Transition Metal Complexes  2.4.4. Metal–carbon bond  2.5. Polymer chemistry  2.5.1. Polymerization mechanism  2.5.2. Polymer Characteristics  2.5.3. Biodegradable Polymer  2.5.4. Conducting polymer  2.5.5. Supramolecular polymers  2.6. Medicinal chemistry  2.6.1. Drug design and development  2.6.2. Pharmacokinetics and pharmacodynamics  2.6.3. Structure-activity relationships  2.6.4. Molecular docking and drug screening
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Crystal field theory  3.1.2. Ligand field theory  3.1.3. Spectrochemical Series  3.1.4. Chelation and stability  3.2. Organometallic Chemistry  3.2.1. Metal Carbonyls  3.2.2. Catalysis by organometallic complexes  3.2.3. Metallocenes  3.3. Bio-inorganic chemistry  3.3.1. Metalloproteins and enzymes  3.3.2. The role of metals in biological systems  3.3.3. Metal ion transport and storage  3.4. Solid state chemistry  3.4.1. Crystal Structures  3.4.2. Band theory of solids  3.4.3. Superconductors  3.4.4. Defects in the crystal  3.5. Lanthanides and Actinides  3.5.1. Electronic configuration in lanthanides and actinides  3.5.2. Coordination chemistry of the lanthanides  3.5.3. Magnetic Properties of Lanthanides
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.2. Spectroscopic Techniques  4.2.1. Atomic absorption spectroscopy  4.2.2. X-ray diffraction  4.2.3. Inductively coupled plasma spectroscopy  4.3. Electroanalytical methods  4.3.1. Potentiometry  4.3.2. Voltammetry  4.3.3. Colometry  4.4. Mass Spectrometry  4.4.1. Ionization Technique  4.4.2. Fragmentation Pattern  4.5. Chemometrics  4.5.1. Multidisciplinary analysis  4.5.2. Machine Learning in Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.1.1. Force fields and energy minimization  5.1.2. Monte Carlo simulation in molecular dynamics simulations  5.2. Quantum chemical methods  5.2.1. Hartree–Fock theory  5.2.2. Density functional theory  5.2.3. Semi-empirical methods  5.3. Computational drug design  5.3.1. Molecular Docking  5.3.2. QSAR Modeling  5.3.3. Virtual Screening
  6. Biochemistry  6.1. Enzyme Kinetics  6.1.1. Michaelis-Menten kinetics  6.1.2. Inhibition mechanism  6.2. Metabolism and Bioenergetics  6.2.1. Glycolysis  6.2.2. Citric acid cycle  6.2.3. Electron transport chain  6.3. molecular Biology  6.3.1. DNA replication and repair  6.3.2. Protein synthesis  6.3.3. Gene Regulation  6.4. Structural Biochemistry  6.4.1. Protein Folding  6.4.2. Membrane Biophysics
  7. Environmental Chemistry  7.1. Atmospheric Chemistry  7.1.1. Greenhouse gases  7.1.2. Ozone depletion  7.1.3. Air pollutants and smoke  7.2. Water Chemistry  7.2.1. pH and water hardness  7.2.2. Wastewater treatment  7.2.3. Aquatic Chemistry  7.3. Soil Chemistry  7.3.1. Heavy metal contamination  7.3.2. Soil pH and Buffering  7.3.3. Nutrient cycling  7.4. Toxicology and Chemical Safety  7.4.1. Toxicokinetics  7.4.2. Risk Assessment in Toxicology and Chemical Safety in Environmental Chemistry  7.4.3. Effects of pollutants on the environment

Graduate → Biochemistry ↓


Metabolism and Bioenergetics


Metabolism is a series of chemical reactions that maintain life in organisms. It is composed of two main categories: catabolism, which breaks down molecules to produce energy, and anabolism, which builds molecules from smaller units and consumes energy. These processes allow organisms to grow, reproduce, maintain their structures, and respond to their environments.

Bioenergetics refers to the study of the transformations of energy in living organisms and the mechanisms of these transformations. It is a key aspect of understanding how cells produce and manage energy, which is vital for all biological activities.

Basic concepts of metabolism

Before going deeper, let's understand two essential terms: enzyme and substrate. Enzymes are proteins that catalyze chemical reactions without being consumed in the process. The substrate is the substance on which the enzyme acts.

Chemical reactions in metabolism

Metabolic pathways are sequences of chemical reactions, each of which is catalyzed by a specific enzyme. For example, the overall reaction for the breakdown of glucose in cellular respiration is:

C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy

This equation shows the catabolic process of breaking down glucose into carbon dioxide and water, releasing energy in the form of ATP, which is adenosine triphosphate, the energy currency of the cell.

Anabolism

Anabolism involves synthesizing complex molecules such as proteins, nucleic acids, and carbohydrates from simpler molecules. These reactions require energy, often provided by ATP. An example of an anabolic reaction is the synthesis of protein from amino acids:

Amino Acids → Proteins

Bioenergetics in Metabolism

Bioenergetics helps us understand how energy flows through living systems. Biological energy transformations typically involve molecules such as ATP, NADH, and FADH 2. Here's how these molecules behave in metabolic processes:

ATP: Energy currency

ATP stores energy in its high-energy phosphate bonds. When a cell needs energy, ATP is often converted into adenosine diphosphate (ADP) and an inorganic phosphate, releasing energy in the process:

ATP → ADP + Pi + energy

This energy release powers a variety of cellular processes, including muscle contraction, nerve impulse transmission, and chemical synthesis.

Visualization of ATP structure

adenine Ribose exemplary exemplary exemplary ATP Structure

The ATP molecule consists of three main parts: adenine (a nitrogenous base), ribose (a five-carbon sugar), and three phosphate groups (represented as pi). The energy of ATP is stored primarily in the bonds between the phosphate groups.

Role of electron carriers

Electron carriers such as NAD + and FAD play important roles in both aerobic and anaerobic respiration. These molecules can accept and donate electrons, acting as intermediaries in redox reactions:

NAD + + 2e− + H + ⇌ NADH
FAD + 2e - + 2H + ⇌ FADH 2

Visualization of NADH

N Advertisement H NADH Structure

NADH and FADH 2 are used in the electron transport chain, which takes place in the mitochondria of eukaryotic cells. This process involves several complex substances that transfer electrons through a membrane to drive the production of ATP.

Glycolysis and the Citric Acid Cycle

Two main processes in the breakdown of glucose, glycolysis and the citric acid cycle, are important components of cellular respiration. Let's explore these processes:

Glycolysis

Glycolysis is the first step of glucose metabolism, which occurs in the cytoplasm. It converts one glucose molecule into two molecules of pyruvate, leading to a net gain of two ATP and two NADH molecules:

Glucose + 2NAD + + 2ADP + 2Pi → 2pyruvate + 2NADH + 2ATP + 2H 2 O

Citric acid cycle

Also known as the Krebs cycle or TCA cycle, this process takes place in the mitochondria. Pyruvate is decarboxylated into acetyl-CoA, which enters the cycle. Three NADH, one FADH 2, and one GTP (or ATP) are produced at each turn of the cycle:

Acetyl-CoA + 3NAD + + FAD + GDP + Pi → 2CO 2 + 3NADH + FADH 2 + GTP + CoA

Visualization of the citric acid cycle

Citrate oxaloacetate Isocitrate α-ketoglutarate

This cycle ensures the gradual release of stored chemical energy through the oxidation of acetyl-CoA. This harnessed energy is then used for the synthesis of ATP, thereby completing the production of carbon dioxide from the original glucose.

Electron transport chain

The electron transport chain (ETC) is the final step of cellular respiration, where high-energy electrons from NADH and FADH 2 pass through the I-IV complex, ultimately converting oxygen to water. The energy from the electrons is used to pump protons across the mitochondrial membrane, creating a proton gradient:

NADH + H + + 1/ 2O2 + ADP + Pi → NAD + + H2O + ATP

Visualization of the electron transport chain

Complex I Complex IIEdit Complex IIIEdit Complex IVEdit

The protons flow back into the mitochondrial matrix via ATP synthase, leading to the synthesis of ATP in a process called oxidative phosphorylation. This mechanism is the most efficient for ATP production.

Conclusion

Through these processes, metabolism and bioenergetics reflect the complex coordination of biochemical reactions that sustain life. Understanding this flow of energy through metabolic pathways is critical to understanding cellular energy dynamics and how organisms interact with their environment. This knowledge provides important insights into diseases, energy production in biofuels, and many other areas of scientific inquiry.


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