Microbiology lecture ch.1-4

What is microbiology?

The study of organisms too small to be seen with the naked eye.

What are the three domains of life?

Bacteria, Archaea, Eukarya.

Difference between normal microbiota, transient microbes, and opportunistic pathogens?

• Normal = permanent, beneficial.

• Transient = temporary.

• Opportunistic = normally harmless, cause disease when defenses are low.

Example of an emerging infectious disease(EID)?

SARS-CoV-2, Zika, Ebola, MRSA, Candida auris.

Who disproved spontaneous generation with the swan-neck flask experiment?

Louis Pasteur.

Who developed postulates linking microbes to specific diseases?

Robert Koch.

What pathogen causes MRSA and skin abscesses?

Staphylococcus aureus.

What are the three main chemical bonds?

Ionic(transfer), covalent(sharing), and hydrogen bonds(weak, DNA/protein folding).

Why is water important to cells?

Solvent, polar, temp buffer, hydrogen bonding. Essential for biochemical reactions and cellular structure.

What does pH measure?

concentration of hydrogen ions.

List the 4 macromolecules of life.

Carbohydrates, lipids, proteins, nucleic acids.

What causes protein denaturation?

Heat, pH changes, chemicals.

What is ATP?

Energy currency of the cell, used in metabolic processes.

What pathogen causes gas gangrene?

Clostridium perfringens.

How do you calculate total magnification in a compound microscope?

Ocular lens x objective lens.

Brightfield vs. Darkfield microscopy?

Brightfield = stained, normal background. Darkfield = unstained, background dark.

What stain is used for Mycobacterium and Nocardia?

Acid-fast stain.

What stain identifies capsules?

Negative stain (halo effect)

What stain uses malachite green + heat?

Endospore stain.

What pathogen causes most duodenal ulcers?

Helicobacter pylori.

Key difference between prokaryotic and eukaryotic cells?

Prokaryotes: circular DNA, no organelles, binary fission. Eukaryotes: nucleus, organelles, mitosis.

What is a glycocalyx and its two forms?

Sticky outer layer. Capsule (organized, virulence) and slime layer (loose, biofilm).

What are fimbriae vs. pili?

Fimbriae = attachment. pili= DNA transfer/motility.

What is the main difference between Gram+ and Gram- cell walls?

Gram+ = thick PG, teichoic acids. Gram- = thin PG, LPS outer membrane.

What part of LPS is toxic in Gram- bacteria?

Lipid A (endotoxin).

What structures target bacterial ribosomes (70S)?

Antibiotics: tetracyclines, aminoglycosides, macrolides.

What are endospores?

Resistant, dormant structures formed by Bacillus and Clostridium.

What pathogen causes “currant jelly” sputum in pneumonia?

Klebsiella pneumoniae.