4.2: Bio molecules: Molecules of Life

• Biomolecules


  Molecules of Life
• Average Composition of biomolecules in Cell

  • Carbohydrates
  • Proteins
  • Lipids
  • Nucleic Acids
• Carbohydrates


  • Composed of carbon, hydrogen, and oxygen in a 1:2:1 empirical ratio
  • General empirical formula is CnH2nOn
• Functions of Carbohydrates


  • Provide energy source
  • Provide energy storage
  • Structural Building Material
• Classes of Carbohydrates


  • Monosaccharides (simple sugars)
  • Disaccharides
  • Polysaccharides (complex carbohydrates)

  
• Monosaccharides


  The building blocks for all other Carbohydrates
• Monosaccharides


  • May exist in a linear molecule or in ring forms
  • Classified according to the number of carbon atoms in their molecule (5 carbons are pentoses, 6 carbons are hexoses)
  • Many forms exist as isomers

  
• Disaccharide Formation and Structure


  Two monosaccharides are joined by dehydration synthesis reaction
• Polysaccharides


  • Long chains of monosaccharides/sugars that have been joined by many dehydration synthesis reactions
  • Function depends on the type of isomer of monosaccharides used in the formation

  
• Lipids


  Greasy or oily nonpolar organic molecules, often with one or more fatty acid tails

  
• Fatty acid


  Consists of a long chain of carbon atoms with an acidic carboxyl group at one end

  
• Glycerol


  Simple Lipid
• Functions of a Lipid


  • Energy storage
  • Waterproofing
  • Insulation
  • Cushioning
  • Regulating metabolic processes
  • Building component of cell membranes

  
• Fats


  Lipids with one, two, or three fatty acid tails

  
• Triglyceride


  Lipid with three fatty acid tails attached to a glycerol backbone

  
• Triglyceride formation


  Dehydration synthesis reaction between glycerol and three fatty acids
• Saturated and Unsaturated Fats


  • Saturated fats pack more tightly than unsaturated fats, and tend to be more solid
• Phospholipids


  The main structural component of cell membranes, a lipid with a phosphate group in its hydrophilic head, and two nonpolar fatty acid tails

  
• Proteins


  Organic compounds consisting of one or more amino acids. A protein's function depends on its structure, which consists of chains of amino acids that twist and fold into functional domains.
• Amino acid


  Small organic compound with a carboxyl group, amine group, and a characteristic side group (R)
• Protein Functions


  • Structure
  • Regulation of metabolic processes
  • Carrying out of metabolic processes
  • Membrane component
  • Self and non-self recognition
  • Membrane receptors
• Peptide Bond, Dipeptide, and Polypeptide Formation

  Amino acids are linked into chains by peptide bonds
• Protein Structure


  • Primary structure (polypeptide formation)
  • Secondary structure
  • Tertiary structure
  • Quaternary structure
  • Fibrous proteins may aggregate into a larger structure
• Viruses


  Parasites that invade cells, have either DNA or RNA protected by a protein coat called a CAPSID, and direct the synthesis of new virus within a host cell
• Why are some viruses harmful? Virus invades cell, forces cell to make copies of virus, eventually so many copies are made, the cell explodes, releasing all of the new viruses
• Examples of some viral diseases


  • AIDS (HIV)
  • Wart (Herpes Simplex Virus)
  • Flu (Influenza)
  • Measles (Morbillivirus)
  • Hepatitis B
• Virus size


  Viruses range in size from 20 nanometers (nm) – 250 nanometers (nm)
• Helical Capsids


  • Rod-like structures with the RNA in the center of the helix, made by stacking repeating units in a spiral
• Bacteriophage


  A virus that infects bacteria
• Viruses


  Newly made viruses infect other cells
• Components of a virus


  • DNA
  • CAPSID
  • VIRUS
• Why some viruses are harmful


  • Virus invades cell
  • Virus forces cell to make copies of virus
  • Eventually so many copies are made, the cell explodes, releasing all of the new viruses
• When your cells make viruses instead of operating normally

  YOU get sick
• Virus size


  • Viruses range in size from 20 nanometers (nm) – 250 nanometers (nm)
  • 1 nm = 0.00000004 inches
  • If a cell was the size of your classroom, then an average virus would be the size of a softball
• Helical capsids


  • Rod-like structures with the RNA in the center of the helix
  • A helix is made by stacking repeating units in a spiral
• Enveloped viruses


  • Viruses which have a membrane coat surrounding the protein coat or capsid
  • Common in animal viruses, but uncommon in plant viruses
• Herpes Simplex Virus


  • A membrane (made of proteins) surrounds the capsid (also made of proteins) which surrounds the viral DNA
• Prokaryotes


  • Cells that do not have a nucleus
  • Exist almost every where on earth
  • Grow in numbers so great you can see them with the unaided eye
  • Are placed in either the Eubacteria or the Archebacteria Kingdoms
• Eubacteria


  • Make up the larger of the two prokaryote kingdoms
  • Generally are surrounded by a cell wall composed of complex carbohydrates
• Cyanobacteria


  • Photosynthetic bacterium
  • Bluish-greenish color
  • Contain membranes that carry out the process of photosynthesis
  • Do not contain the same type of chloroplasts as plants do
  • Can survive in extremely hot environments and even extremely cold environment