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Molecules of Life

Molecules of Life. Kathy Huschle Northland Community and Technical College. Why Chemistry in a Microbiology Class?. the science of the interaction between atoms and molecules is chemistry the metabolic activities of microorganisms involve complex chemical reactions. Molecules of Life .

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Molecules of Life

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  1. Molecules of Life Kathy Huschle Northland Community and Technical College

  2. Why Chemistry in a Microbiology Class? • the science of the interaction between atoms and molecules is chemistry • the metabolic activities of microorganisms involve complex chemical reactions

  3. Molecules of Life • all matter, air, rock or a living organism – is made up of atoms • a single type of atom is called an element C – carbon H – hydrogen O – oxygen N - nitrogen Carbon Hydrogen Oxygen Nitrogen

  4. MOLECULES • atoms interact to form molecules H2O – water CO2 – carbon dioxide • molecules interact to form macromolecules which include proteins, polysaccharides, lipids, nucleic acid

  5. Atoms • atoms are made up of • electrons, protons, neutrons • # of protons, which have a positive charge equals the number of electrons, which have a negative charge • neutrons, found in the nucleus of the atom along with the protons, are neutral particles • electrons move about he nucleus in regions called electronic shells

  6. Elements • there are 92 naturally occurring elements • 4 elements; carbon, hydrogen, oxygen, nitrogen, make up 99% of all living material, by weight • phosphorus and sulfur make up another 0.5% of the elements of living systems

  7. Atoms

  8. Chemical Bonds • molecules are made up of 2 or more atoms • to be stable an atom needs a maximum number of electrons in the electron shell • electrons are gained from atoms, or lost to other atoms • to gain or lose an electron, atoms form molecules: held together by a chemical bond

  9. Types of Chemical Bonds • ionic • covalent • hydrogen

  10. Ionic Bond • a positively or negatively charged atom is called an ion • the chemical attraction between ions of opposite attraction is an ionic bond • one ion is an electron donor, the other ion is an electron acceptor

  11. Covalent Bond • atoms share pairs of electrons • stronger than ionic bonds • more common in organisms

  12. Hydrogen Bonds • weak bonding resulting from intermolecular forces of attraction • results when a hydrogen bonded to a O or N in one molecule and is attracted to a O or N in another molecule

  13. Hydrogen Bond • water is a good example of hydrogen bonding • the water molecule is constantly being formed and broken at room temperature • ice forms with 4 hydrogen bonds, making the structure more rigid

  14. Chemical Compounds of the Cell • water • over 70% of living organisms by weight • H bonding is important in the properties of water • universal solvent of life

  15. Water

  16. pH • potential hydrogen • degree of acidity of the solution • narrow range for microbial survival is near neutral

  17. pH

  18. pH

  19. pH

  20. Small Molecules • inorganics: makes up about 1% of the dry weight of microbes • sodium, potassium, magnesium, calcium iron, chloride, phosphate, sulfate

  21. Small Molecules • organics: are the result of the cells metabolism of sugar • amino acids, purines, pyrimidines sugars • all are considered precursor metabolites: converted to the building blocks of large molecules

  22. Small Molecules • ATP: adenosine triphosphate • storage form of energy for the cell • broken bonds release energy

  23. Macromolecules • very large molecules – several thousand atoms each • 4 major classes • proteins, polysaccharides, nucleic acids, and lipids • differ from each other in their chemical structure

  24. Macromolecules • common feature of macromolecules • all are polymers • formed by the joining of small molecules (subunits)

  25. Proteins • 50% of the dry weight of cells • most versatile: bacterial cells contain 600-800 different proteins such as • enzymes: proteins that speed up bio-chemical reactions • bacteriocins: proteins produced by some bacteria for killing of other bacteria • toxins: proteins produced by disease-causing microorganisms

  26. Proteins • microbial world proteins are responsible for • all reactions required for life • structure and shape • cell movement • bringing in nutrients • turning genes on and off • critical to properties of cell membrane

  27. Proteins

  28. Proteins • made up of a combination of 20 major amino acids • amino acids consist of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur

  29. Proteins • protein properties depend mainly on its shape • dependent on arrangement of amino acids • held together with peptide bonds • type of covalent bonding

  30. Protein A PROTEIN MUST HAVE ITS PROPER SHAPE TO FUNCTION

  31. Proteins • denaturation: the process by which a protein loses its characteristic shape • denaturing can occur many ways including • high temperature • increase or decrease of pH • solvent • peptide bonds are broken • protein no longer functions in its proper role • in some cases denaturing is reversible, in others it is not • Protein Folding Problem • probable cause of many neurodegenerative diseases • research for Alzheimer's disease is studying denatured proteins in regard to prions (small particle of protein)

  32. Denatured Protein

  33. Carbohydrates • all carbohydrates contain C, H, O • approximate ratio of 1:2:1 • include sugars and starches • classified as • monosaccharides • disaccharides • polysaccharides

  34. Carbohydrates • monosaccharide • classified by the # of carbon atoms they contain • 5 carbon sugars ribose and deoxyribose are found in RNA and DNA

  35. Carbohydrates • disaccharides • 2 monosaccharides joined by a covalent bond • lactose and sucrose

  36. Carbohydrates • polysaccharides • cellulose: the most abundant organic molecule on Earth • glycogen: carb storage product of animals and some bacteria

  37. Carbohydrates • polysaccharides • dextran: synthesized by bacteria as a storage product

  38. Nucleic Acids • carry genetic info in all cells • genetic info found in nucleic acid is decoded into the sequence of amino acids then passed on to the protein molecule • 2 types of nucleic acid • DNA – deoxyribonucleic acid • RNA – ribonucleic acid

  39. Nucleic Acid hydrogen bond covalent bond • DNA • master molecule of the cell • all cell properties are determined by DNA • coded • made up of two complementary strands held together by hydrogen bonding

  40. Nucleic Acid • RNA • decodes DNA information into amino acid sequence for protein molecules • single stranded

  41. Lipids • indispensable to the cell • structure of all membranes • gatekeepers of the cells • keep cell’s internal contents inside • allows for quick uptake of nutrients • very slight solubility in water

  42. Lipids • simple lipids • contain only carbon, hydrogen, oxygen • fats: made up of fatty acids & glycerol • saturated: solid • unsaturated: liquid

  43. Lipids • compound • contain elements other than C, H, O • phospholipids • contain phosphate molecule in addition to fatty acids and glycerol compound lipid

  44. Lipids • phospholipids • tail of the phospholipid is hydrophobic (water repelling) • head of the phospholipid is hydrophilic (water attracting

  45. Lipids • phospholipids are key structures in the cell membrane

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