History of Disease Theory

• Ancient belief that bad air causes diseases is Miasma Hypothesis
• Aqueducts were built by the Romans to remove 'bad air', as they believed it caused diseases.
• Hippocrates is considered the Father of Western medicine who believed diseases came from the environment.
• Thucydides was a Greek historian who observed that survivors of the Plague became immune.
• Antonie van Leeuwenhoek was the first to observe microorganisms using a microscope.
• Robert Koch proved that specific microbes cause specific infections.
• Ignaz Semmelweis demonstrated that hand disinfection reduces infections in expecting mothers.
• Joseph Lister created the practice of preventing infection by using sterile techniques during surgery.
• Edward Jenner developed a process of introducing a vaccine to stimulate immunity against a disease.
• Microorganisms are microscopic organisms including bacteria, fungi, protozoa, and viruses.
• The taxonomic system is the science of classifying and organizing living organisms into categories
• Carl Linnaeus created the taxonomic system

Hierarchy of Taxons

• The eight levels of classification in biology are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
• A trick to remember the eight levels of classification: (KING PHILIP CAME OVER FOR GOOD SOUP)

Writing a Scientific Name

• Use initials
• Indicate the table number
• Genus name is capitalized
• Species name is lowercase

DNA Sequencing Steps

• Extract DNA by collecting and isolating DNA from a sample.
• Amplify DNA using PCR (Polymerase Chain Reaction) in order to make many copies of the DNA.
• Label DNA by adding markers or special tags to help identify the sequence.
• Use machine to Read the Sequence to determine the order of the nucleotides (A, T, G, C) in the DNA.

Autotrophic Organisms

• Growth Test: Grow in media without organic food (like glucose); if they grow, they are autotrophs.
• Light Test: Grow in light but not in darkness; if they grow, they are photosynthetic autotrophs.
• Chemical Test: Grow using chemicals like hydrogen sulfide; if they grow, they are chemosynthetic autotrophs.

Heterotrophic Organisms

• Growth Test: Grow in media containing organic carbon (like glucose); if they grow, they are heterotrophs.
• Heterotrophs do not require light for growth. They rely on organic material, not photosynthesis.
• If they only grow with organic compounds (like sugars or proteins), they are heterotrophs.

Identifying Cells

• Look for a Nucleus: If a cell has a nucleus, it is likely a eukaryote. If there's no nucleus, it is a prokaryote.
• Check for Organelles: Eukaryotes have organelles like mitochondria and chloroplasts, while prokaryotes don't have membrane-bound organelles.

Biochemical Testing

• Sugar Test: Check if the microbe can break down sugars (e.g., glucose).
• Catalase Test: Put hydrogen peroxide on the microbe; if it bubbles, the microbe has the enzyme catalase.
• Urease Test: If the microbe breaks down urea, it changes the color of the test medium.

Types of Stains

• Gram Stain: Stains bacteria purple (Gram-positive) or pink (Gram-negative).
• Endospore Stain: Stains tough spores to help identify certain bacteria.