Chapter 1

Examples of pathogenic microbes :: Clostridium tetani → tetanus; Mycobacterium tuberculosis → tuberculosis; pathogens cause disease in humans

True pathogen vs opportunistic pathogen :: True = infects healthy people; Opportunistic = infects when immune system weak or wrong site; opportunistic ≠ harmless

Robert Hooke contribution :: First to observe and describe cells

Antonie van Leeuwenhoek contribution :: First to observe bacteria (“animalcules”); initially ridiculed

Louis Pasteur contributions :: Disproved spontaneous generation; pasteurization; vaccines (rabies, anthrax); supports germ theory

Robert Koch contributions :: Linked specific microbes to specific diseases; Koch’s postulates

Ignaz Semmelweis contribution :: Handwashing reduces infections

Joseph Lister contribution :: Antiseptic surgery; sterilization techniques

Florence Nightingale contribution :: Hospital sanitation and aseptic nursing practices

Pasteur swan-neck experiment :: Broth stayed sterile unless exposed; proved biogenesis (life comes from life)

Aseptic techniques definition :: Practices to prevent contamination (handwashing, sterilization, gloves)

Importance of aseptic techniques :: Prevent healthcare-associated infections; protect patients

Classification hierarchy :: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

Three domains of life :: Bacteria, Archaea, Eukarya

Why protists not true kingdom :: Too diverse; not evolutionarily related

Why biological species concept doesn’t apply to microbes :: Reproduce asexually; defined by DNA similarity instead

Strain definition :: Genetic variant within a species

Why strains matter :: Different virulence and antibiotic resistance

Symbiosis types :: Parasitism (+/−); Mutualism (+/+); Commensalism (+/0)

Why commensalism debated :: Most interactions affect both organisms slightly

Human Microbiome Project goal :: Study microbes in/on human body

Functions of normal microbiota :: Compete with pathogens; digestion; vitamin production; immune training (ALL apply)

Factors affecting microbiome :: Birth method; breastfeeding; antibiotics; environment

Biofilm definition :: Community of microbes in protective matrix

Biofilm importance :: Resistant to antibiotics; hard to remove; causes infections (catheters, teeth)

pH scale concept :: Each pH unit = 10x change; pH 1 vs 5 = 10,000x more acidic

Organic molecule definition :: Must contain carbon-hydrogen (C-H) bonds

ATP definition :: Energy currency of cell; nucleotide

Proteins function :: Many roles (enzymes, structure, signaling)

Lipids function :: Membrane structure; energy storage; NOT water soluble

Size of bacteria :: Typically 1–10 µm

Bacterial motility :: Movement via flagella

Bacterial reproduction :: Binary fission

Gram-positive vs Gram-negative :: Gram + = thick peptidoglycan; Gram − = outer membrane + LPS; Gram − more resistant

What can cross membrane freely :: Small nonpolar molecules (O₂)

Osmosis definition :: Movement of water across semipermeable membrane

Prokaryote vs eukaryote :: Eukaryotes have nucleus + organelles; prokaryotes do not

Why antifungal drugs toxic :: Fungi are eukaryotic → similar to human cells

Central dogma :: DNA → RNA → protein

tRNA function :: Brings amino acids to ribosome

Silent mutation :: DNA change with no amino acid change

When mutations occur :: During DNA replication

What ALL viruses have :: Genetic material

What SOME viruses have :: Envelope

How viruses recognize host cells :: Protein–protein interactions

Transduction definition :: Bacteriophage-mediated gene transfer

Viral antigenic structure :: Spike proteins trigger immune response

What ALL cells have :: Ribosomes