Lecture on CHNOPS Elements in Living Organisms

Introduction

• CHNOPS: Acronym for Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur
  • Most common elements in living organisms
  • Make up 98% of living matter on Earth
  • Understanding CHNOPS helps in grasping biochemical reactions

Composition in Organisms

• 99.7% of bacteria
• 97.9% of humans
• 96.2% of humans are made of Carbon, Hydrogen, Nitrogen, and Oxygen

Key Elements

Carbon

• Makes up 18% of humans by mass
• Backbone of biological molecules (proteins, carbohydrates, lipids, nucleic acids)
• Has 4 valence electrons allowing various bonds (single, double, triple)
• Silicon has similar properties, suggesting potential for silicon-based life

Hydrogen

• Makes up 10% of humans
• Integral to water (H₂O)
  • Humans are about 60% water
• Active in ionic form (H⁺)
  • Involved in acid-base behavior in biochemical reactions

Nitrogen

• Essential for DNA (nitrogenous bases)
• Found in amine groups (amino acids)
• Makes up 3% of humans
• Abundant in the atmosphere (78%)

Oxygen

• Major component of water (H₂O)
• Makes up 65% of human body mass
• Important in oxidizing reactions (electron grabbing)
• Antioxidants may reduce internal oxidation

Phosphorus

• Found in DNA backbone and ATP
• Involved in phosphorylation (signals and conformation changes in molecules)
• Component of phospholipids in cell membranes
• Makes up 1% of humans

Sulfur

• Found in amino acids cysteine and methionine
• Forms disulfide bridges in proteins
• Makes up 0.25% of humans

Calcium

• Makes up 1.5% of human body
• Found in bones and teeth
• Important in ion form for neuron signaling and muscle contraction

Trace Elements

• Iron for hemoglobin
• Sodium and Potassium as electrolytes for signaling/neuron function
• Iodine for thyroid hormones

Conclusion

• Next focus: Interaction of elements, forming biological molecules
• Challenge: Identify a biological molecule with only CHNOPS elements

Community Engagement

• Encouraged audience interaction through comments
• Invitation to support on Patreon for more content