1. Microbiology: A Systems Approach
PowerPoint to accompany
Microbiology: A Systems Approach
Cowan/Talaro
Chapter 2
The Chemistry of Biology
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2. Chapter 2
Topics
Fundamental Building Blocks
Macromolecules
The Cell

3. Fundamental Building Blocks
Atoms
Elements
Molecules and compounds

4. Atoms Proton Neutron Electron Atomic number = no. of protons
Atomic mass = no. of protons and neutrons

5. Models showing the hydrogen atom and its subatomic particles (protons, neutrons, and electrons).
Fig. 2.1 Models of atomic structure

6. Element (atom)
Varied subatomic particles (atomic no. and mass) make-up specific elements
Elements are important for structure and function of the cell

7. Major elements found in microbial cells and their significance.
Table 2.1 The major elements of life and their primary characteristics

8. Molecules and compounds
Molecule = combination of two or more elements (ex. H2)
Compound = combination of two or more different elements (ex. H2O)
Molecules are held together by chemical bonds

9. Chemical bonds
Covalent
Ionic
Hydrogen

10. Chemical bonds involve atoms sharing, donating or accepting electrons
Fig. 2.3 General representation of three types of bonding

11. Hydrogen gas, molecular oxygen, and methane are examples of covalent bonding (atoms sharing electrons).
Fig. 2.4 Examples of molecules with covalent bonding

12. Polarity can occur with different types of covalent bonding (ex. H2O)
Fig. 2.5 Polar molecule

13. Sodium chloride (table salt) is an example of ionic bonding (electron transfer among atoms or redox reaction).
Fig. 2.6 Ionic bonding between sodium and chlorine

14. Ionic bonding molecules breakup (ionization) when dissolved in a solvent (water), producing separate positive and negative particles.
Figure 2.7 Ionization

15. Hydrogen bonding is the attraction between the positive hydrogen ion and a negative atom. An example would be water molecules.
Fig. 2.8 Hydrogen bonding in water

16. The pH of an environment (exterior or interior of a cell) is important for living systems.
Fig The pH scale

17. Molecules Consist of inorganic and organic molecules.
Inorganic – C or H is present (ex. CO2, H2)
Organic- C and H are present (ex. CH3)

18. The carbon in inorganic and organic molecules is the basic fundamental element of life. Functional groups (R) bind to these carbons.
Table 2.3 Representative
functional groups and
classes of organic
compounds

19. pH scale pH – measurement of the H+ ion concentration General rule:
Acidic = excess H+ ions in solution
Basic = excess OH- ions in solution
Neutral = equal amounts of H+ and OH- ions

20. Macromolecules
Carbohydrates
Lipids
Proteins
Nucleic acids

21. Carbohydrates
Sugars
Polysaccharides

22. Major sugars (monosaccharides) in the cell are glucose, galactose and fructose. Several sugars bonded together are called polysaccharides.
Fig Common classes of carbohydrates

23. Sugars are bonded by glycosidic bonds
Sugars are bonded by glycosidic bonds. Water is released (dehydration) after the bond is formed.
Fig Glycosidic bond

24. Peptidoglycan in bacteria is an example of a polysaccharide.
Fig Polysaccharides

25. Lipids
Triglycerides
Phospholipids
Steroids

26. Triglycerides are important storage lipids (ex. Fats and oils)
Fig Synthesis and structure of a triglyceride

27. Phospholipids serve as a major structural component of cell membranes.
Fig Phospholipids-membrane molecules

28. Cholesterols are associated with cell membranes of some cells
Cholesterols are associated with cell membranes of some cells. They bind to the fatty acid of a lipid.
Fig Formula for cholesterol.

29. Proteins Proteins are the predominant organic molecule in cells
Proteins consist of a series of amino acids (ex. Peptides, polypeptides)
Peptide bonds link amino acids
Examples: enzymes, antibodies, etc.

30. Amino acids vary based on their reactive (R) groups present.
Fig Structural formula of selected amino acids

31. The are 20 natural occurring amino acids.
Table 2.5 Twenty amino acids and their abbreviations

32. A peptide bond forms between the amino group on one amino acid and the carboxyl group on another amino acid.
Fig The formation of a peptide bonds in a tetrapeptide

33. Proteins take on a variety of shapes, which enables specific interactions (function) with other molecules.
Fig Stages in the formation of a functioning protein

34. Nucleic acids Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
DNA contains genetic information and transfers it to RNA
RNA translates the DNA information into proteins

35. Nucleic acids are polymers of repeating units called nucleotides.
Fig The general structure of nucleic acids

36. The pentose sugars and nitrogen bases determine whether a molecule will be DNA or RNA.
Fig The sugars and nitrogen bases that make up DNA
and RNA.

37. The DNA configuration is a double helix.
Fig A structural representation of the double helix of DNA

38. DNA serves as a template for the synthesis of new DNA, mRNA, tRNA and rRNA.
Fig Simplified view of DNA replication in cells.

39. The Cell Fundamental characteristics Reproduction Metabolism
Motility (Response to molecules)
Protection and Storage (Cell wall or membrane)
Nutrient transport