1. The Chemistry of Microbiology
Chapter 2

2. Atoms Matter is anything that takes up space and has mass
The smallest and basic chemical unit is an atom
Consist of negatively charged electron which orbit around the uncharged neutrons and positive charged protons
Elements is matter composed of a single type of atom

3. Atoms
The atomic number depends on the number of protons in the nucleus in the atom
The atomic mass is the sum of all the protons, neutrons, and electron. We mainly add the protons and neutrons and not the electrons because the electron have little mass.
Isotopes are atoms of an element that differ only in the numbers of neutrons they contain

4. Chemical Bonds
Electron shells are the region of space occupied by electrons
The atom’s reactivity depends on the number of electrons on the outermost shell, or valence electrons.
Chemical bond is when electrons are transferred or shared to complete the valence shell.
The first shell only holds two electrons and the rest shells hold a maximum of eight electrons

5. Chemical Bonds
Electronegativity is the strength of the atom’s attraction for electrons
The electronegativity determines whether the bond is going to be a nonpolar covalent bond, a polar covalent bond, or an ionic bond
Nonpolar covalent bond is equal sharing of the electrons.
Polar covalent bond is unequal sharing of the electrons
Ionic bond is a bond in which one or more electrons from one atom are removed and attached to another atom
Positive charged ions are called cations and negatively charged ions are called anions

6. Chemical Bonds
Molecule consist of two or more atoms held together by a chemical bond
A molecule that contains atoms of more than one element is a compound
Organic compounds that contain carbon and hydrogen atoms are called organic compounds
Hydrogen bond is the electrical attractions between a partially charged hydrogen atom and a full or partial negative charge on either a different region of the same molecule or another molecule.

7. Chemical Reaction
A process where reactants are changed into products by making or breaking chemical bond results in a chemical reaction
Synthesis reactions form larger, more complex molecules
In dehydration synthesis a molecule of water is removed from the reactants as the larger molecule is formed
Endothermic reaction requires energy
Anabolism is the sum of all synthesis reaction in an organism

8. Chemical Reaction
Decomposition reactions break larger molecules into smaller molecule
Exothermic reaction releases energy
Hydrolysis is a decomposition reaction that uses water as one of the reactants
Catabolism is the sum of decomposition reaction in an organism
Exchange reactions involve exchanging atoms between reactants
The sum of all anabolic, catabolic, and exchange chemical reactions in an organism is metabolism

9. Water, Acids, Bases, and Salts
Inorganic molecules lack carbon
Water is a vital inorganic compound because of its properties as a solvent
Acids release hydrogen ions
Bases release hydroxyl anions
The pH scale measures the hydrogen ion concentration in a substance
Buffers are substances that prevent drastic changes in pH
Salt is a compound that dissociates in water into cations and anions.

10. Organic Macromolecules
Functional groups are found in organic macromolecules
Monomers are simple subunits that can be covalently linked to form polymers
Lipids (include fat, phospholipids, waxes, and steroids) are hydrophobic (repel water) macromolecules

11. Organic Macromolecules
Fat molecules are formed from a glycerol and three chainlike fatty acid
Saturated fatty acid which contains more hydrogen in their structural formulas than unsaturated fatty acid
Unsaturated fatty acid contains double bond between some carbon acid
Polyunsaturated fat are double bonds that exist in the fatty acids of a molecule of fat

12. Organic Macromolecules
Phospholipids contain two fatty acid chains and a phosphate functional group. The phospholipid head is hydrophilic, where the fatty acid is hydrophobic
Waxes contain a long chain fatty acid covalently linked to a long chain alcohol. It is also components of cell wall and used as energy storage molecules
Steroid lipids (Cholesterol) help maintain the structure of the membrane as the temperature increases
Carbohydrates (monosaccharaides, disaccharides, and polysaccharides) serve as energy sources and structural molecule

13. Organic Macromolecules
Protein are structural components of cells, enzymatic catalyst, regulators of various activities, molecules involved in the transportation of substances, and defensive molecules
Denaturation of a protein disrupts its structure and its function
Also, they are composed of amino acids linked by peptide bonds, and they possess primary, secondary, and tertiary structure

14. Organic Macromolecules
Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) are unbranched macromolecular polymers of nucleotides, each composed either of deoxyribose or ribose sugar, ionized phosphate, and a nitrogenous base.
Five nitrogenous bases: Adenine, Guanine, Cytosine, Thymine, and Uracil.
DNA consist of A, G, C, and T
RNA consist of A, G, C, and U
Nucleic acids structure allows genetic diversity

15. Organic Macromolecules
Adenosine triphosphate (ATP) is the most important short-term energy storage molecule in the cell.