Biochemistry

• Starch is linked by glycosidic bonds
• metabolism is the summary of all the chemical reactions within a living organism
• Ion dipole interactions


  Between caesium ions and oxygen atoms of OH groups
• Uses of Enzymes


  • Oil spill can be fixed using bacterium possessing enzymes
  • Immobilised enzymes are used to treat industrial wastewater
  • Used to make lactose free milk
  • Enzymes such as hydrolases, break down the stains of fats, proteins
• Biomagnification


  The increase in concentration of a substance as it passes up the food chain
• For biomagnification to occur

  • Substance should not be broken by environment
  • Substance should not be broken by body
  • Substance should be lipid soluble, so it's not excreted by stored in fat
• Example of Biomagnification


  • DDT is a widely used pesticide in agriculture
  • DDT found its way into rivers and lakes
  • Taken in by microscopic plants, eaten by small animals, eaten by fish and eaten by larger fish, then birds
  • DDT got higher in concentration on the way up
  • Birds were affected as the shells in their eggs became too weak to bear the weight of the mother
• Green chemistry


  Sustainable chemistry: approach to chemical research and industrial process that wishes to minimise the production of hazardous substance, as well as their release to the environment
• Principles of green chemistry


  • Prevention
  • Atom economy
  • Less hazardous chemical syntheses
  • Designing safer chemicals
  • Safer solvents and auxiliaries
  • Design for energy efficiency
  • Renewable feedstocks
  • Reduce derivatives
  • Catalysis
  • Design for degradation
  • Real time analysis for pollution prevention
  • Inherently safer chemistry for accident prevention
• Atom economy


  • Molar mass of desired product/total molar mass of all reactants X 100%
  • Measures how efficient a particular reaction is in terms of converting as much of starting materials into desired product
• Host-guest chemistry


  A form of supramolecular chemistry
• Supramolecular chemistry


  • Deals with systems larger than a single molecule
  • DNA is an example of a supramolecular assembly
• Enzyme-substrate interaction


  The substrate (guest) does not form covalent bonds to the groups in the active enzyme site (host), rather is held by interactions
• Interactions holding substrate to enzyme


  • London forces
  • Hydrogen bonds
  • Ionic interactions
• Enzymes


  • Recognise substrate molecules
  • Molecular recognition is important to host-guest chemistry
• Host molecules


  Can be made to mimic enzymes: be selective and catalyse
• Applications of host-guest chemistry

  Removing toxic materials
• What removes heavy metal ions?

  • Calixarenes
  • Cuplike molecules used to remove highly radioactive caesium ions from radioactive waste and to extract uranium ions from water
• Calixarenes


  Form ion dipole interactions between caesium ions and oxygen atoms of OH groups
• Plastics from alkenes


  • Non-biodegradable, meaning microorganisms cannot break them apart due to strong carbon-carbon covalent bonds
  • Must be dealt with via incineration, landfill sites, or recycling
• Bioplastics


  Plastics made from renewable materials
• Biodegradable plastics


  Plastics that can be broken by bacteria
• Biodegradable and compostable plastics


  • Thermoplastic starch
  • Polylactic acid (PLA)
• Starch has been used in making bioplastics and biodegradable plastic
• Because starch used in plants, organisms have the necessary enzymes to break it down to glucose
• The glucose is readily respired into carbon dioxide and water
• PLA


  A polyester from lactic acid, which is obtained from corn starch via fermentation, and is biodegradable under certain conditions due to ester groups between monomers
• There is debate about how friendly PLA is for the environment


  • Lots of land used to grow GM corn for plastics, as opposed to food
  • PLA only degrades quickly in an industrial composter
• Thermoplastic starch


  Used as an environmentally friendly plastic substitute
• Xenobiotics


  Compounds found in living organisms that should not be normally found there
• Xenobiotics


  • Medicines
  • Pesticides
  • Drugs
  • Plasticizers
  • Dyestuff
• How pharmaceuticals enter water


  1. Excretion of urine and feces

  2. Washing and showering (sweat)

  3. Flushing medicine down toilet

  4. Agriculture- drugs given to animals
• Xenobiotics are found in drinking water in small amounts, can over time be bad
• Vitamins


  Micronutrients, essential in small amounts for a functioning body
• Vitamins


  • Cannot be made in the body, besides vitamin D
  • Must be ingested from foods
• Categories of vitamins


  • Fat soluble
  • Water soluble
• Water soluble vitamins


  • Have polar groups, eg OH, and can form hydrogen bonds with water
  • Can be urinated out
• Fat soluble vitamins


  • Normally nonpolar, have long hydrocarbon chains
  • Stored in the body
• Vitamin C (ascorbic acid)


  • Water soluble, contains multiple OH groups and other oxygens
  • Lets them form hydrogen bonds
  • Plays a key role in tissue growth and repair; synthesises collagen, a connective tissue
  • Acts as antioxidant, protecting body from free radical damage
  • Found in fruits, mostly citrus, and veggies
  • Scurvy can result from Vitamin C deficiency
• Vitamin A (retinol)


  • Fat soluble, long hydrocarbon chain with hydrocarbon ring
  • Contains an OH group, but the polar nature cannot offset the entire nonpolar molecule
  • Important for vision, growth and development, skin repair and immune system
  • Found in animal products: egg and liver
  • Can be formed in body from precursor provitamin B-carotene, found in veggies and fruits such as carrots
  • Deficiency can lead to xerophthalmia, severe drying of eye