Biochemistry

• Element


  A substance that cannot be broken down to other substances by chemical reactions
• There are 92 elements, each with its own chemical symbol
• Compound


  A substance of two or more different elements combined in a fixed ratio
• Compounds


  • Table salt (NaCl)
  • Water (H2O)
• 20-25% of the elements are essential elements required for life
• Atom


  The smallest unit of matter that still retains the properties of an element
• Atom


  • Made of subatomic particles (neutrons, protons and electrons)
  • Each element contains a unique type of atom not found in any other element, with a differing number of protons
  • All atoms of a specific element have the same number of protons in each nucleus (atomic number)
  • Neutrally charged atoms have the same number of electrons as protons
  • The (atomic) mass number also includes the mass of neutrons
• Protons and electrons


  Electrically charged particles
• Atom structure


  • Protons and neutrons are packed together in the core of the atom (nucleus)
  • Electrons form a cloud of negative charge circling the nucleus
  • The attraction between opposite charges (negative electron and positive proton) prevents the electrons from escaping the atom
• Isotopes


  Different atomic forms of the same element, with the same number of protons but different numbers of neutrons
• Naturally occurring isotopes different to those described in the periodic table are often rare (e.g. 99% of naturally occurring carbon is carbon-12; the remainder is carbon-13 and carbon-14)
• Radioactive isotopes


  Unstable isotopes that decay spontaneously, giving off particles and energy
• Radioactive isotopes can be readily detected, and are therefore used as "tracers" for metabolic processes
• Water is a very important solvent
• Solution


  A liquid that is a completely homogeneous mixture of two or more substances
• Solvent


  The dissolving agent
• Solute


  The substance that is dissolved
• The quantities of both solvent and solute used determine the concentration
• Hydrophilic


  Substances that "like" water and easily dissolve in it, such as ionic salts
• Hydrophobic


  Substances that "dislike" water and do not easily dissolve in it, such as non-polar molecules like fats
• Molecular mass (Mr)


  The sum of the masses of all the atoms in a molecule
• Mole


  A standard unit containing 6.022 x 10^23 molecules, used to measure the amount of a substance
• Molarity


  The number of moles of solute in 1 litre of solution
• Calculating molarity


  1. Moles = Mass / Molecular mass

  2. Molarity = Moles / Volume (in litres)
• Molarity can be expressed in different units, such as M, mM, μM, and nM
• Making solutions


  1. Calculate the final volume of the solution, not just the volume of the solvent

  2. Add water to the solute to reach the desired final volume
• Diluting solutions


  M1V1 = M2V2, where 1 signifies the conditions before dilution, and 2 the conditions after dilution
• Dilution examples


  • 250 mL of water added to 750 mL of 0.8 M NaCl solution, final concentration is 0.6 M
  • Dilute 30 mL of 12 M HCl to 0.35 M, final volume is 1029 mL
  • Dilute 2 M stock solution to make 25 mL of 0.5 M solution, need 6.25 mL of stock
• Denaturation refers to the loss of protein function due to changes in its shape or conformation caused by heat, pH change, or other factors.
• Protein folding involves hydrogen bonds between amino acids, disulfide bridges (covalent), ionic interactions, van der Waals forces, and hydrophobic interactions.
• Protein folding involves hydrogen bonds between amino acids, disulfide bridges (covalent), ionic interactions, van der Waals forces, and hydrophobic interactions.
• The three-dimensional structure of proteins is determined by the primary, secondary, tertiary, and quaternary structures.
• The three-dimensional structure of proteins is determined by the primary, secondary, tertiary, and quaternary structures.
• Proteins are denatured when their tertiary structure is disrupted, leading to a loss of biological activity.
• Proteins are denatured when their tertiary structure is disrupted, leading to a loss of biological activity.
• Enzymes are proteins that catalyze biochemical reactions in living organisms.
• Chemical reaction


  The breaking and making of chemical bonds to form different products
• Reactants


  The starting materials
• Products


  The final materials
• The ability of molecules to be converted from one form to another allows for the incredible diversity seen in life