protein \polysachride \nucleic acids\ structure of proteins

• Proteins


  Polypeptides, linear chains of amino acids linked by peptide bonds
• Types of amino acids

  • Alanine
  • Cysteine
  • Proline
  • Tryptophan
  • Lysine
• Proteins are heteropolymers, not homopolymers
• Essential amino acids


  Amino acids that must be supplied through diet
• Non-essential amino acids


  Amino acids that the body can make
• Functions of proteins


  • Transport nutrients across cell membrane
  • Fight infectious organisms
  • Hormones
  • Enzymes
• Collagen is the most abundant protein in the animal world
• Ribulose bisphosphate Carboxylase-Oxygenase (RuBisCO) is the most abundant protein in the whole of the biosphere
• Polysaccharides


  Long chains of sugars, threads containing different monosaccharides as building blocks
• Cellulose


  A polymeric polysaccharide consisting of only one type of monosaccharide, glucose
• Starch


  A variant of cellulose, a store house of energy in plant tissues
• Glycogen


  A variant of starch, found in animals
• Inulin


  A polymer of fructose
• Reducing end


  The right end of a polysaccharide chain
• Non-reducing end


  The left end of a polysaccharide chain
• Starch forms helical secondary structures and can hold I2 molecules in the helical portion
• Cellulose does not contain complex helices and hence cannot hold I2
• Plant cell walls are made of cellulose
• Paper made from plant pulp and cotton fibre is cellulosic
• Complex polysaccharides


  Have amino-sugars and chemically modified sugars as building blocks, mostly homopolymers
• Chitin


  A complex polysaccharide found in arthropod exoskeletons
• Nucleic acids


  Polynucleotides, macromolecules found in living tissues/cells
• Nucleotide


  The building block of nucleic acids, containing a heterocyclic compound, a monosaccharide, and a phosphoric acid
• Nitrogenous bases in nucleic acids

  • Adenine
  • Guanine
  • Uracil
  • Cytosine
  • Thymine
• Purine


  The skeletal heterocyclic ring of adenine and guanine
• Pyrimidine


  The skeletal heterocyclic ring of uracil, cytosine, and thymine
• DNA


  Nucleic acid containing deoxyribose
• RNA


  Nucleic acid containing ribose
• Primary structure of proteins

  The sequence of amino acids, the positional information in a protein
• 1. terminal amino acid


  The first amino acid in a protein
• 1. terminal amino acid


  The last amino acid in a protein
• Secondary structure of proteins

  The folding of the protein thread into helices and other forms
• Tertiary structure of proteins


  The folding of the long protein chain upon itself, giving a 3-dimensional view
• Quaternary structure of proteins


  The arrangement of individual folded polypeptides or subunits with respect to each other
• Adult human haemoglobin consists of 4 subunits, 2 α-type and 2 β-type