Undergraduate
  1. General chemistry  1.1. Introduction to Chemistry  1.2. Atomic Structure  1.2.1. Subatomic particles  1.2.2. Atomic Model  1.2.3. Quantum numbers  1.2.4. Electron Configuration  1.2.5. Periodic trends  1.2.6. Isotopes and their applications  1.3. Chemical bond  1.3.1. Ionic bond  1.3.2. Covalent bonds  1.3.3. Metal Bond  1.3.4. Hybridization  1.3.5. Molecular geometry and VSEPR theory  1.3.6. Bond polarity and dipole moment  1.4. Stoichiometry  1.4.1. Mole concept  1.4.2. Empirical and molecular formula  1.4.3. Limiting reactant and excess reactant  1.4.4. Percent Yield and Purity  1.4.5. Dilution calculation  1.5. States of matter  1.5.1. Gas Laws  1.5.2. Matter and Intermolecular Forces  1.5.3. Solid and Crystal Structures  1.5.4. Phase diagram  1.5.5. Plasma and supercritical fluid  1.6. Chemical reactions  1.6.1. Types of Chemical Reactions  1.6.2. Balancing Chemical Equations  1.6.3. Thermochemical reactions  1.6.4. Reaction energy profiles  1.7. Solutions and Mixtures  1.7.1. Concentration units  1.7.2. Syndrome properties  1.7.3. Solubility and Solubility Rules  1.7.4. Henry's Law and Raoult's Law  1.7.5. Partition coefficient  1.8. Chemical equilibrium  1.8.1. Law of mass action  1.8.2. Le Chatelier's principle  1.8.3. Reaction quotient  1.8.4. To use this online calculator for Equilibrium Constant, enter Equilibrium Constant (Eq.) and hit the calculate button. Here is how the Equilibrium Constant calculation can be explained with given input values -> 0.05 = 0.05/0.  1.8.5. Acid-base balance  1.9. Acids and bases  1.9.1. Arrhenius, Brønsted–Lowry, and Lewis definitions  1.9.2. pH and pOH  1.9.3. Acid-base titration  1.9.4. Buffer Solution  1.9.5. Acid-base indicator  1.9.6. Polyprotic Acids and Bases  1.10. Electrochemistry  1.10.1. redox reactions  1.10.2. Galvanic and Electrolytic Cells  1.10.3. Nernst equation  1.10.4. Electrolysis  1.10.5. Faraday's laws of electrolysis  1.11. Thermodynamics  1.11.1. Laws of Thermodynamics  1.11.2. Enthalpy, entropy and Gibbs free energy  1.11.3. Spontaneity of reactions  1.11.4. Thermodynamic cycles (Hess's law, Carnot cycle)  1.12. Kinetics  1.12.1. Rate law and reaction order  1.12.2. Activation Energy and Catalyst  1.12.3. Collision theory  1.12.4. Reaction mechanism  1.12.5. Transition state theory
  2. Organic chemistry  2.1. Structure and relationships  2.1.1. Hybridisation in Carbon Compounds  2.1.2. Resonance and aromatization  2.1.3. Molecular orbitals  2.1.4. Inductive and mesomeric effects  2.2. Hydrocarbons  2.2.1. Hydrocarbons  2.2.2. Alkene  2.2.3. Alkynes  2.2.4. Aromatic compounds  2.2.5. Cycloalkanes and Conformation  2.3. Functional Group  2.3.1. Alcohols and phenols  2.3.2. Ethers and epoxides  2.3.3. Aldehyde and ketone  2.3.4. Carboxylic acids and derivatives  2.3.5. Amin  2.3.6. Esters and amides  2.3.7. Thiols and sulfides  2.4. Stereoscopic  2.4.1. Isomerism in Stereochemistry  2.4.2. Chirality and optical activity  2.4.3. Structural analysis  2.4.4. Diastereomers and Enantiomers  2.5.1. Substitution reactions  2.5.2. Elimination reactions  2.5.3. Addition reactions  2.5.4. Radical reactions  2.5.5. Rearrangement reactions  2.5.6. Pericyclic Reactions  2.6. Spectroscopy and structural analysis  2.6.1. Infrared Spectroscopy  2.6.2. Nuclear magnetic resonance spectroscopy  2.6.3. Mass Spectrometry  2.6.4. UV-visible spectroscopy  2.6.5. X-ray crystallography  2.7. Polymer chemistry  2.7.1. Addition and Condensation Polymers  2.7.2. Polymerization mechanism  2.7.3. Biodegradable Polymer  2.7.4. Conducting and smart polymers
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Ligands and coordination compounds  3.1.2. Crystal field theory  3.1.3. Molecular Orbital Theory in Coordination Compounds  3.1.4. Jahn–Taylor distortion  3.2. Main Group Chemistry  3.2.1. Alkali and alkaline earth metals  3.2.2. Halogens and Noble Gases  3.2.3. Transition metals and their complexes  3.2.4. Lanthanides and Actinides  3.3. Solid state chemistry  3.3.1. Crystal lattices and unit cells  3.3.2. Defects in solids  3.3.3. Electrical and magnetic properties  3.3.4. Superconductivity  3.4. Bio-inorganic chemistry  3.4.1. Metal ions in biology  3.4.2. Enzymatic reactions with metals  3.4.3. Metal poisoning and detoxification  3.4.4. Metalloproteins and Metalloenzymes
  4. Physical chemistry  4.1. Quantum Chemistry  4.1.1. Wave–particle duality  4.1.2. Schrödinger Equation  4.1.3. Quantum Numbers and Orbitals  4.1.4. Atomic and molecular spectroscopy  4.2. Statistical mechanics  4.2.1. Maxwell–Boltzmann distribution  4.2.2. Partitioning functions  4.2.3. Bose–Einstein and Fermi–Dirac statistics  4.3. Chemical thermodynamics  4.3.1. Gibbs Free Energy  4.3.2. Phase transition  4.3.3. Thermodynamic efficiency  4.4. Surface chemistry  4.4.1. Absorption and Catalysis  4.4.2. Colloids and Emulsions
  5. Analytical Chemistry  5.1. Classical methods  5.1.1. Gravimetric Analysis  5.1.2. titrimeter  5.2. Instrumental methods  5.2.1. Chromatography  5.2.2. Spectroscopy  5.2.3. Electroanalytical methods  5.2.4. X-ray diffraction
  6. Industrial Chemistry  6.1. Petrochemistry  6.2. Chemical engineering principles  6.3. Green Chemistry  6.4. Pharmaceuticals and Drug Synthesis
  7. Biochemistry  7.1. Carbohydrates  7.2. Proteins and enzymes  7.3. Lipids and membranes  7.4. Nucleic acids  7.5. Metabolism and Bioenergetics  7.6. Enzyme kinetics and mechanism

Undergraduate → Inorganic chemistry → Bio-inorganic chemistry ↓


Metal poisoning and detoxification


Bioinorganic chemistry is an exciting field that studies the role of metals in biology. While metals are essential to life, enabling processes such as oxygen transport and electron transfer, they can also be toxic. Understanding metal toxicity and detoxification is important, especially in today's industrial society where exposure to metals is significant.

The role of metals in biology

Iron (Fe), copper (Cu), zinc (Zn), manganese (Mn) and other metals are vital to life. They are essential for a variety of biological processes:

  • Iron: Central component of hemoglobin and myoglobin, important for oxygen transport and storage.
  • Copper: Required for enzymes such as cytochrome c oxidase involved in cell respiration.
  • Zinc: Important for enzymes such as carbonic anhydrase, which regulates pH and carbon dioxide transport.

However, an imbalance in metal concentrations can cause poisoning. Toxic metals such as lead (Pb), mercury (Hg), and cadmium (Cd) can disrupt normal bodily functions. Let's explore the mechanisms of metal poisoning.

Mechanisms of metal toxicity

Metals can be toxic by a variety of mechanisms, and can affect cells and tissues in harmful ways:

  • Oxidative stress: Metal ions can participate in redox reactions, generating reactive oxygen species (ROS) that damage proteins, DNA, and lipids.
  • Enzyme inhibition: Toxic metals can replace essential metal cofactors in enzymes, inhibiting their function. For example, lead can inhibit enzymes that use calcium.
  • Protein misfolding: Metals can bind to proteins, causing them to fold incorrectly or aggregate, leading to cellular dysfunction.

Example: Lead is known to displace calcium ions in biological systems, thereby disrupting processes such as muscle contraction and neurotransmission. This displacement can inhibit various important enzymes that depend on calcium for activation.

Visual example: metal displacement

M + Ca^2+ - enzyme ⟶ [Ca(enzyme)] → Activity Pb^2+ (displacing) M + Pb^2+ - enzyme ⟶ [Pb(enzyme)] → Inhibition

Detoxification mechanisms in living organisms

Living organisms have evolved mechanisms to detoxify metals and minimize their harmful effects:

1. Metallothionein

Metallothioneins are small proteins rich in cysteine, a sulfur-containing amino acid. They bind to metal ions via sulfur atoms, keeping them separated and preventing toxicity.

Metal^2+ + Metallothionein → Metal + Metallothionein Complex

2. Chelation

Chelating agents are molecules that can form stable complexes with metal ions. They are used both biologically and medically to detoxify metals.

Example: Ethylenediaminetetraacetic acid (EDTA) is a synthetic chelating agent used to treat lead and calcium overdose in humans.

3. Enzymatic conversion

Some enzymes convert toxic metals into less toxic forms. An example of this is the conversion of arsenate (AsO43-) to arsenite (AsO33-), which can be further disposed of through methylation.

Visual example: chelation process

Metal^2+ + EDTA^4− ⟶ [Metal(EDTA)]^2- Complex

Case study: mercury poisoning and detoxification

Mercury is a highly toxic metal that exists primarily in two forms: elemental mercury (Hg) and methylmercury (CH3Hg+). Methylmercury is particularly dangerous because it accumulates in the food chain.

Toxic effects of mercury

Mercury affects the nervous system and can cause cognitive impairment and motor dysfunction. It also affects the kidneys and immune system.

Detoxification of mercury

Several detoxification pathways help reduce mercury toxicity:

  • Glutathione conjugation: Glutathione reacts with mercury to form compounds that can be excreted from the body.
  • Microbial methylation: Certain bacteria can methylate inorganic mercury, making it more volatile and facilitating environmental detoxification.

Visual example: mercury detoxification

Hg^2+ + 2 GSH → Hg(SG)_2 + 2H^+

Preventing metal poisoning

In addition to biological detoxification mechanisms, prevention is an important strategy. Reducing exposure to toxic metals can significantly reduce the likelihood of poisoning

  1. Regulation of industrial emissions: Industries must follow strict guidelines to minimize emissions of toxic metals into the environment.
  2. Safe disposal of waste: Environmental pollution can be prevented by proper disposal of metal containing waste.
  3. Personal protective equipment (PPE): Individuals working in industries involving metals should use PPE to minimize exposure.

Challenges and future directions

Despite progress in understanding metal toxicity and detoxification, challenges remain. The complex interactions between various metals and biological molecules require further exploration.

Future directions

  • Advanced analytical techniques: Advances in technology can provide new methods for detecting and quantifying metal concentrations in biological systems.
  • Bioremediation strategies: Developing organisms or consortia capable of detoxifying metals faster and more efficiently is a promising area of research.
  • Nanotechnology applications: Using nanoparticles for targeted delivery of chelating agents or other detoxification tools.

Conclusion

Understanding metal toxicity and detoxification is important to maintain a balance between the essentiality and toxicity of metals. Through awareness and scientific advancements, we can better manage the effects of metals in biological systems and the environment. Both prevention strategies and detoxification mechanisms play a vital role in this effort, ultimately contributing to better health and environmental outcomes.


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Metal poisoning and detoxification

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