Chemicals of Life

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  • Created by: Pops!
  • Created on: 10-01-17 19:31

Biological Molecules pt.1

  • Carbon atoms bond strongly to each other forming chains and rings
  • Carbohydrates include monosaccharides, disaccharides and polysaccharides
  • Monosaccharides include glucose, fructose and galactose (have same chemical formula but different chemical structures - isomers)
  • Monosaccharides can become linked together by a glycosidic bond to form disaccharides e.g. maltose, sucrose, lactose and polysaccharides e.g. starch, cellulose
  • Polysaccharides can perform structural roles e.g. cellulose in plant cells and energy storage roles e.g. starch in plants and animals
  • Lipids are composed of carbon, hydrogen and oxygen (non-polar and insoluble in water)
  • Lipids used as energy stores, insulation and protection e.g. cell-membrane structure inc. fats oils, phospholipids, waxes and steroids
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Biological Molecules pt.2

  • Fats and oils are condensation products of fatty acids and glycerol
  • Fatty acids have varying length hydrocarbon tails (also unsaturated or saturated)
  • Phospholipids similar to triglycerides but a phosphate replaces a fatty acid
  • Proteins are condensation polymers of up to 20 different amino acids, have many functions e.g. enzymes, hormones, antibodies, transport, structural
  • Amino acids have amino group, carboxyl group and a differing R group
  • Amino acids linked by peptide bonds as a result of condensation reactions
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Biological Molecules pt.3

  • PRIMARY STRUCTURE = sequence of amino acids
  • SECONDARY STRUCTURE = arrangement of polypeptide chain into a helix orpleated sheet
  • TERTIARY STRUCTURE = folding of secondary structure to give 3D shape
  • QUATERNERARY STRUCTURE = association of 2 or more polypeptide chains to give protein
  • Fibrous proteins e.g. collagen, kertatin, elastin form tough fibres that give support
  • Globular proteins e.g. enzymes, antibodies, hormones are involved in cellular reactions
  • Water is a fundamental biological molecule - is an important slovent, involved in biochemical reactions and temperature regulation
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Enzymes

  • Globular proteins, properties relates to tertiary strucutre
  • Speed up the rate of eactions by lowering activation energy
  • Combines complementary substrate to form an ENZYME-SUBSTRATE COMPLEX
  • Specific because they only act on a particular substrate
  • Unchanged after reaction so can be re-used
  • Temp, pH and conc of reactants affect rate of enzyme-catalysed reaction
  • Can be prevented from working by competitive and non-competitive inhibitors
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Enzymes

  • Globular proteins, properties relates to tertiary strucutre
  • Speed up the rate of eactions by lowering activation energy
  • Combines complementary substrate to form an ENZYME-SUBSTRATE COMPLEX
  • Specific because they only act on a particular substrate
  • Unchanged after reaction so can be re-used
  • Temp, pH and conc of reactants affect rate of enzyme-catalysed reaction
  • Can be prevented from working by competitive and non-competitive inhibitors
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Nucleic Acids and Protein Synthesis

  • Chromosomes made of long, super-coiled strand of DNA
  • Gene codes for the production of a particular protein
  • DNA molecule is a double helix with COMPLEMETARY BASE PAIRING
  • Sequence of bases = genetic code read off in base triplets (codons)
  • Each codon codes for particular amino acid
  • Able to make new DNA by semi-conservative replication
  • DNA can make mRNA by transcription (carries coded info from DNA to ribosomes)
  • tRNA carries specific amino acids to the ribosomes to be assembled into protein
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