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Home , Alexander Fleming, Archaea, Germ theory of disease, Ignaz Semmelweis, John Snow, Joseph Lister

Chapter 1: Introduction

1. Overview of the Microbial World

2. Brief History of

3. Ecological Roles of Microbes 1. Overview of the Microbial World Evolutionary Tree of *

* *

* covered in this course Archaea: “tongue” • prokaryotic “”

Bacteria: • colonize all but the most extreme environments • chemically and metabolically very different from archaea Fungi Characteristics of Fungi: • all are eukaryotic heterotrophs (eat “organic” food) • unicellular (yeasts) or multicellular (, mushrooms) • walls made of chitin

yeast Protists are mostly single-celled : – heterotrophic protists (“-like”) – photosynthetic protists (“-like”) trypanosome (alga) (protozoan) Helminths roundworms () & Helminths = (Platyhelminthes)

• invertebrate phyla in the Animal • many helminths are -causing parasites

Trichinella () “tapeworm” (platyhelminth) Non-cellular, “non-living” entities. tobacco mosaic • cannot function without cell • frequently T4 pathogenic

adenovirus 2. Brief History of Microbiology The Discovery of Anton van was the first to observe microorganisms in 1673 using his rather sophisticated (for the ) “magnifying lenses”.

• essentially began the of microbiology

• the importance of microorganisms for human welfare was not appreciated until almost 200 years later! The Golden Age of Microbiology Many landmark discoveries in microbiology occurred in the last half of the :

• the first (cowpox lesions to prevent ) • (1789)

• importance of aseptic techniques in • (1848) – • (1854) – general • (~1860) – use of surgical

• the first epidemiological study (identifying the source of a outbreak) • John (1854) Contributions of • proposed “Germ ” of disease (1857) • disproved concept of (1861) • i.e., microbes do NOT arise from non-living material

• showed to be carried out by microbes (1861)

• developed technique of pasteurization

• developed several attenuated Contributions of • identified the first bacterial : • anthracis ( – 1876) • (tuberculosis – 1882) • proposed method to identify the microbial agent responsible for a given disease (Koch’s Postulates)

• developed numerous advances in microbiological techniques: • simple methods • fixation of specimens to slides • use of solid growth media • pure culture techniques • methods for counting microbes Other Landmarks in Microbiology

• first evidence of viruses (tobacco mosaic virus) • Dmitri Ivanowski (1892) • the first synthetic chemicals • Paul Erlich (1908)

• discovery of the first () • (1928)

• discovery of • Stanley Prusiner (1997) 3. Ecological Roles of Microbes Microbes & Microorganisms play many essential roles in ecosystems, without which life on our planet would collapse:

Nitrogen fixation

• conversion of atmospheric (N2) into “bio-available” and compounds • makes nitrogen available for and, indirectly, all other organisms (necessary for , etc) • photosynthetic microbes support aquatic food webs • essential for the recycling of nutrients Microbes & Humanity Microorganisms provide many benefits for human beings: Internal and external health benefits • gut microbes provide digestive help, important nutrients, protection from pathogenic organisms • normal skin and mucosal microbes provide protection from pathogenic organisms Food production • wine, cheese, bread, yogurt, etc, depend on microbes and pest control • treatment, cleanup of various pollutants, etc **very few microbes actually human disease** Key Terms for Chapter 1

• archaea • heterotroph • protozoa, algae • helminth • spontaneous generation •

Relevant Chapter Questions rvw: 2, 5 MC: 2, 3, 5-7 Chapter 2: Chemical Principles

1. Atoms & Molecules

2. Biological 1. Atoms & Molecules Atomic Structure Atoms are composed of: Protons (positively charged, 1 amu) nucleus Neutrons (no charge, 1 amu) Electrons (negatively charged, negligible mass) amu = “atomic mass unit”; atomic mass = protons + neutrons • # of protons determines element

• different isotopes of an element contain diff. # of neutrons

• electrons (e-) exist in # of e- = p+ in a neutral atom orbitals, w/in e- shells Electron Configurations Molecules & Covalent Bonds

“Happy” atoms have NO partially filled electron shells!

Molecular weight (MW) = sum of atomic masses in a molecule Atoms share electrons to fill electron shells • sharing of unpaired e- = covalent bond • basis of molecules (multiple atoms joined by cov. bonds) Water & Bonding Water is a polar molecule due to polar O-H bond: • polar covalent bond = electron pair shared unequally • nonpolar covalent bond = electron pair shared equally • hydrogen bonds are weak interactions between opposite partial charges due to polar bonds & Ionic Bonds Ions have gained or lost an electron(s),

…and can form ionic bonds due to the attraction of oppositely charged ions. Water as a Water’s polar makes it a great solvent for other polar or charged substances.

• polar water molecules neutralize and shield the solute

*doesn’t work for nonpolar solutes (e.g., oils)* Ionic Compounds Dissociate in Water

Acids (release H+ ions), bases (release OH- ions which then combine with H+), and (ionic compounds w/o OH- or H+) all dissolve and dissociate (split) into ions very easily in water. , Bases & pH Acids release H+ ions into solution • raise [H+] • lower pH Bases remove H+ ions from solution • lower [H+] • raise pH

pH = –log of [H+]

[H+] x [OH-] = 10-14 M buffers are molecules that resist pH change 2. Biological Molecules Functional Groups

common molecular groups found in organic molecules Carbohydrates

Simple sugars • mono- and disaccharides (e.g., glucose, sucrose) Complex carbohydrates • polysaccharides (e.g., starch, glycogen, ) Biological roles: • source • structure, physical support & protection • adhesion, molecular “recognition” Hydrophobic (nonpolar) biological molecules: • fatty acids • triglycerides • • steroids

Biological roles: • membranes, energy source & storage, communication Phospholipids & Membranes Phospholipids have “polar heads”, “nonpolar tails”

• form a bilayer in water

• the major component of biological membranes (which have and proteins as well) Proteins Polymers of amino acids connected by bonds (i.e., polypeptides).

• made from 20 amino acids (differ in their “R” groups)

• proteins have extremely diverse biological roles 1o Structure 2o Protein function is entirely dependent on protein structure.

o Protein structure 3 is entirely dependent on the amino 4o sequence. Nucleic Acids DNA, RNA • polymers of • store genetic info • expression

ATP • direct source of energy in cells Key Terms for Chapter 2

• isotope, atomic mass, molecular weight • valence • covalent bond, ionic bond, hydrogen bond • polar vs nonpolar bond • solvent, solute • acid, base, , pH, buffer • carbohydrate, lipid, protein,

Relevant Chapter Questions rvw: 1-7, 10-14 MC: 1-10