Macromolecules

• Cells are the fundamental units of life
• Cells stick together and communicate with one another
• Chemical components of a cell

  • Oxygen
  • Carbon
  • Hydrogen
• Compounds


  Two or more atoms chemically bound together
• A compound has characteristics quite different from those of its elements
• Molecule


  Two or more atoms bound together
• Compound


  Two or more different atoms bound together
• Around 1060 compounds with drug-like features can be made, which is more than the number of atoms in the solar system
• Less than 10,000 drugs have been approved for medical use
• Most viruses enter cells through receptor-mediated endocytosis
• 47 AAK1 inhibitors have been approved for medical use, and 6 inhibited AAK1 with high affinity
• AAK1: AP2-associated protein kinase 1, GAK: cyclin G-associated kinase
• Baricitinib is the first immunomodulatory treatment for COVID-19 to receive FDA approval

  
• Carbon


  Very stable, readily available, can form 4 bonds, can bond to other carbons and other elements, can form single/double/triple bonds and ring structures, allows for the formation of large/complex/varied molecules, contributing to the diversity of organisms

  
• Essential biomolecules of life

  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids
• All species inherited the same basic chemical structures and processes from a common ancestor
• Macromolecules of life


  • DNA/RNA
  • Carbohydrates
  • Proteins
  • Lipids
• Carbohydrates


  The most abundant biomolecule, serve as fuel and building material, cells extract energy from glucose molecules to produce ATP, simple sugars' carbon skeletons serve as raw material for the synthesis of other types of small organic molecules
• Polysaccharides


  Extensively branched structure with more free ends available for hydrolysis, providing energy from different ends more rapidly
• Lactose intolerance


  Lacking the enzyme lactase to break down lactose, leading to digestive issues
• Recommendations for lactose intolerant patients: take lactase when eating or drinking dairy products, consume lactase-treated products
• Diagnostic tests for lactose intolerance: hydrogen breath test, lactose tolerance test
• Lipids


  Consist mostly of hydrocarbon regions, hydrophobic, vary in form (fats are solid at room temperature, oils are liquid at room temperature), major function is energy storage
• Saturated vs unsaturated lipids

  Saturated lipids have no double bonds and are fully packed, resulting in higher melting/boiling points. Unsaturated lipids have double bonds and are not fully packed, resulting in lower melting/boiling points.
• Steroids


  Distinguished by the particular chemical groups attached to the ensemble of rings
• Proteins


  Nearly every dynamic function of a living being depends on proteins, account for over 50% of the dry mass of most cells, constructed from 20 amino acids linked by peptide bonds
• Noncovalent bonds


  Help proteins fold and stabilize their 3D structure, including hydrogen bonds, ionic bonds, and van der Waals forces
• Protein folding


  Also aided by hydrophobic forces, with polar amino acid side chains on the surface and nonpolar side chains buried
• Factors that can denature proteins: changes in pH, salt concentration, temperature
• Around 1/3 of newly synthesized proteins in eukaryotes may not achieve their native conformations, and proteins are constantly exposed to damaging conditions
• Protein functions


  • Catalysis
  • Transport
  • Structural
  • Signaling
  • Immune defense
  • Movement
• Protein activation and inhibition

  Involve similar mechanisms of conformational changes, binding, and post-translational modifications
• In sickle-cell disease, the substitution of glutamic acid with valine in hemoglobin changes its polarity and ability to carry oxygen
• Nucleic acids


  Polymers of nucleotides, play important roles in energy and information transfer, including DNA and RNA
• Nucleotides


  Building blocks of nucleic acids, also serve as energy-transferring compounds (ATP, ADP), signal transduction molecules (cAMP), and enzyme cofactors (NAD+, NADP+, FMN, FAD, coenzyme A)
• DNA is more stable than RNA due to the extra hydroxyl group in RNA making it more prone to hydrolysis, and DNA's double-stranded structure better protects the genetic information and allows for easier repair
• Under normal cellular conditions, RNA undergoes hydrolysis about 100 times faster than DNA
• Life likely began with either DNA or RNA as the genetic material
• The central dogma describes the flow of genetic information from DNA to RNA to protein
• There are 28 COVID-19 vaccines approved by at least one country, 8 in the WHO emergency use listing, and 9 in Vietnam's emergency use listing