Biomolecules

• Biochemistry


  The study of the chemical constituents of living cells and the reactions and processes they undergo or "the science of the chemical basis of life"
• Biomolecules


  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic Acid
• Monomer


  Smaller unit from which a polymer is formed
• Polymer


  Molecule made from a large number of monomers joined together in a chain
• Supramolecular structure


  Complex structural forms made up of proteins
• Carbohydrates


  • Consist of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the general formula: (CH2O)n, where "n" ranges from 3 to 8
  • Synonymous to "Saccharide" which means sweet tasting crystalline carbohydrates thus they are often called as sugars
  • Has a monomeric unit called monosaccharides
• Lipids


  • Fats, Fatty Acids (and its derivatives) and Sterol containing molecules such as Cholesterols
  • Provides structural support especially in the cell membrane
  • It has no monomeric unit
• Proteins


  • Large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues
  • Responsible for a vast of functions inside the body by forming complex structural forms
  • They are made by monomeric units called Amino acids
  • There are 21 known amino acids
• Nucleic Acids


  • Macromolecules that store genetic information and enable protein production
  • Nucleic acids include DNA and RNA
  • Made up of long monomeric units called Nucleotides
  • Are synthesized by the cell through salvage pathways (from scratch)
  • A, T, C, G
• Organization of Life

  • Elements
  • Simple organic compounds (monomers)
  • Macromolecules (polymers)
  • Supramolecular structures
  • Organelles
  • Cells
  • Tissues
  • Organisms
• Elements of Life


  • Most abundant, essential for all organisms: C, N, O, P, S, H
  • Less abundant, essential for all organisms: Na, Mg, K, Ca, Cl
  • Trace levels, essential for all organism: Mn, Fe, Co, Cu, Zn
  • Trace levels, essential for some organisms: V, Cr, Mo, B, Al, Ga, Sn, Si, As, Se, I
• Biochemistry can be defined as: The study of the chemical constituents of living cells and the reactions and processes they undergo or "the science of the chemical basis of life"
• Biochemical pathways (summary) can be found at https://www.cc.gatech.edu/~turk/bio_sim/articles/metabolic_pathways.png
• Biomedical importance of water


  • Ideal Biological Solvent
  • Its interaction with biomolecules influences their structures
  • An excellent nucleophile
  • Its ability to Dissociate into (OH-) and (H3O+) ions
• Nature Reviews Molecular Cell Biology volume11, pages50–61 (2010) shows the pH of different subcellular compartments
• Dissociation of Water


  1. Experimentally it can be shown that: [H3O+] = [OH−] = 1.0 x 10−7 M at 25 °C

  2. Kw = [H3O+] [OH−]

  3. Kw = 1.0 x 10−14, a constant for all aqueous solutions at 25 °C
• Calculating [OH−] when [H3O+] is known

  Kw = [H3O+][OH−]
• Calculating [H3O+] when [OH−] is known

  Kw = [H3O+][OH−]
• pH Scale


  • Acidic solution: pH < 7, [H3O+] > 1 x 10−7
  • Basic solution: pH > 7, [H3O+] < 1 x 10−7
  • Neutral solution: pH = 7, [H3O+] = 1 x 10−7
• Buffer


  • A solution whose pH changes very little when acid or base is added
  • Most buffers are solutions composed of roughly equal amounts of: A weak acid, The salt of its conjugate base
• General Characteristics of a Buffer

  1. If an acid is added, the excess acid reacts with the conjugate base, so the overall pH does not change much

  2. If a base is added, the excess base reacts with the conjugate acid, so the overall pH does not change much
• Henderson-Hasselbach equation


  Used to calculate pH of a buffer solution
• Acid-Base Titration


  • A graphical representation of the pH of a solution during a titration
  • Titration is the slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of unknown concentration until the reaction reaches neutralization, which is often indicated by a color change
• Equivalence point


  The point during a titration where the reaction reaches neutralization
• The three-dimensional structure of proteins is determined by the primary, secondary, tertiary, and quaternary structures.
• Protein folding involves hydrogen bonds between amino acids, disulfide bridges (covalent), ionic interactions, van der Waals forces, and hydrophobic interactions.
• Denaturation refers to the loss or alteration of protein function due to changes in its shape caused by heat, pH, chemicals, or other factors.