MICROBIOLOGY

FINAL

What is pathogenicity?

The ability of a microbe to cause disease.

What is virulence?

The degree or severity of pathogenicity.

How do microbes adhere to host cells?

Using adhesins such as fimbriae, pili, and surface proteins.

Why is adherence important?

Prevents removal by fluids and allows colonization.

How do capsules increase pathogenicity?

Inhibit phagocytosis and immune recognition.

What cell wall component acts as an endotoxin?

Lipopolysaccharide (LPS) in Gram-negative bacteria.

What does coagulase do?

Clots blood to protect bacteria from immune cells.

What does streptokinase do?

Breaks down clots to spread infection.

What does hyaluronidase do?

Breaks connective tissue to aid invasion.

What is an exotoxin?

A secreted bacterial protein toxin with specific effects.

What is an endotoxin?

LPS from Gram-negative cell walls causing inflammation.

What are A-B toxins?

Toxins with binding (B) and active (A) subunits.

What do cytolytic toxins do?

Lyse host cells by forming pores.

What are superantigens?

Toxins that overstimulate T cells, causing cytokine storms.

What is innate immunity?

Nonspecific defenses present at birth.

What is adaptive immunity?

Specific, learned immune responses (B & T cells).

Difference between passive and active immunity?

Passive = transferred antibodies; Active = body produces antibodies.

First line of defense?

Skin and mucous membranes.

Second line of defense?

Innate responses (phagocytes, inflammation).

Third line of defense?

Adaptive immunity (B cells, T cells).

Types of vaccines?

Live attenuated, inactivated, subunit, toxoid, mRNA.

What is herd immunity?

Population-level protection due to widespread immunity.

Common modes of transmission?

Direct contact, airborne, vector-borne, food/waterborne, zoonotic.

Order of disease stages?

Incubation → Prodromal → Illness → Decline → Convalescence.

Define endemic.

Constant presence in a population.

Define epidemic.

Sudden increase in cases.

Define pandemic.

Worldwide epidemic.

What is epidemiology?

Study of disease distribution and causes.

Evidence for early life on Earth?

Microfossils, stromatolites, isotopic data.

What does endosymbiotic theory explain?

Origin of mitochondria and chloroplasts.

Evidence for endosymbiosis?

Circular DNA, double membranes, ribosomes.

What is the core genome?

Genes shared by all strains.

What is the pan-genome?

All genes across all strains.

Oxygenic photosynthesis produces what?

Oxygen.

Anoxygenic photosynthesis uses what instead of water?

Sulfur or other electron donors.

Lactic acid fermentation organisms?

Lactobacillus, muscle cells.

Alcohol fermentation organisms?

Yeast

Butyric acid fermentation organism?

Clostridium.

Three domains of life?

Bacteria, Archaea, Eukarya.

Culture-dependent methods?

Grow microbes in lab media.

Culture-independent methods?

DNA sequencing, metagenomics.

What does PCR do?

Amplifies DNA.

Difference between microbial species and guild?

Species = genetic similarity; Guild = shared function.

Why is nutrient cycling important?

Recycles essential elements for ecosystems.

Where does the human microbiome come from?

Birth, enviornment, diet

What is fecal microbiota transplantation (FMT)?

Transfer of healthy gut microbes to restore balance.