MICROBIO Lecture 2 Q&A FLASH

These flashcards cover the lecture’s major themes: early vaccination history, antiseptic surgery, public-health milestones, shifts in leading causes of death, emerging infectious diseases, anti-vaccination impact, taxonomy basics, domain differences, bacterial identification methods, and key laboratory concepts.

What early immunization technique was practiced in 5th-century China to prevent smallpox?

Variolation—drying smallpox scabs, grinding them into powder, and having patients snort the material.

Why is Edward Jenner often called the father of vaccination?

He formally documented the use of cowpox (vaccinia virus) to protect against smallpox in 1796.

What observation led Jenner to test cowpox as a vaccine?

Milkmaids who had contracted cowpox did not develop severe smallpox during an epidemic.

How did Jenner test his cowpox hypothesis?

He inoculated an 8-year-old boy with cowpox, then repeatedly exposed him to smallpox; the boy never developed smallpox.

Why did the Academy of Sciences initially reject Jenner’s paper?

His study had only one subject, far below the 100 needed for statistical significance.

Which antiseptic pioneer inspired the name of Listerine?

Joseph Lister.

What chemical did Joseph Lister spray over surgical wounds, and what was the result?

Phenol (carbolic acid); surgical site infections fell from 45 % to 15 %.

List one severe downside of using phenol as an antiseptic.

Phenol is corrosive, neurotoxic, hepatotoxic, nephrotoxic, and carcinogenic—eventually killing Lister and colleagues.

Which two early 20th-century public-health measures caused the first big drop in U.S. infectious-disease mortality?

Creation of state food-inspection departments (after publication of "The Jungle") and chlorination of municipal water.

What was the most lethal pandemic in modern history and roughly how many did it kill?

The 1918 influenza pandemic; about 50–115 million deaths (≈ one-third of the planet at the time).

Before 1900, what were the top three causes of death in the U.S.?

Pneumonia, tuberculosis, and diarrheal diseases (enteritis).

By 1997, what replaced infectious diseases as the top three U.S. killers?

Heart disease, cancer, and stroke—diseases of aging.

Which emerging infection briefly became the leading cause of death for 25- to 44-year-olds in the early 1990s?

HIV/AIDS.

Define an emerging infectious disease (EID).

A disease newly recognized or increasing in incidence/prevalence in the past ~35 years.

Give two pathogen-side reasons diseases emerge.

1) Evolution to infect new hosts (e.g., SIV → HIV). 2) Acquisition of new virulence or resistance genes (e.g., E. coli O157 gaining Shiga toxin).

Give two human-side reasons diseases emerge.

1) Increased global travel and rapid movement of pathogens. 2) Expansion into wildlife habitats / rural areas, increasing exposure to vectors.

What do MDR-TB and XDR-TB stand for?

Multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis.

Why is malaria re-emerging in parts of the southern United States?

Resurgence of Anopheles mosquitoes and drug-resistant Plasmodium strains in endemic areas such as Texas, Louisiana, Mississippi, and Florida.

State one consequence of the modern anti-vaccination movement.

Resurgence of vaccine-preventable diseases like measles and whooping cough due to reduced herd immunity.

What is the Human Microbiome Project?

A multi-year effort to identify and sequence all microorganisms living in and on the human body and study their health effects.

Who developed the binomial system of nomenclature still used today?

Carl Linnaeus (18th century).

In binomial nomenclature, which word is capitalized and which is lowercase?

Genus is capitalized; species is lowercase (both italicized or underlined).

Differentiate between bacillus (capital B) and bacillus (lowercase b).

Capital B refers to the genus Bacillus (spore-forming aerobes like B. anthracis); lowercase b simply means any rod-shaped bacterium.

What term is used for a bacterial category below species?

Strain (e.g., E. coli O157:H7).

Explain the meaning of E. coli O157:H7.

A strain of Escherichia coli identified by serotype: O antigen 157, H antigen 7.

Name the three domains of life in the current classification system.

Bacteria, Archaea, and Eukaryota.

Give one unique feature of archaeal cell membranes.

They contain long-chain ether-linked lipids rather than phospholipids, enabling survival in extreme environments.

What molecule is unique to bacterial cell walls?

Peptidoglycan.

Define prokaryote and eukaryote in terms of nucleus.

Prokaryote lacks a membrane-bound nucleus; eukaryote possesses a true nucleus.

List the five common bacterial shapes.

Coccus (sphere), bacillus (rod), spirillum/spirochete (spiral), vibrio (comma), and pleomorphic/filamentous forms.

What are the three main laboratory methods to identify an unknown microbe?

Phenotyping, serotyping (immunologic), and genotyping.

State one advantage and one limitation of phenotypic identification.

Advantage: inexpensive, requires minimal equipment/training. Limitation: easily confounded by contamination and subjectivity.

What does a serological test detect?

Antigen-antibody reactions specific to a microbe (e.g., rapid strep or COVID-19 tests).

Why is genotypic identification considered the gold standard?

It directly analyzes genetic sequences, giving highly specific and accurate results.

Explain binary fission.

Asexual reproduction in bacteria where the cell duplicates its DNA and divides into two identical daughter cells.

What is hemolysis on blood agar and why is it useful?

Destruction of red blood cells by bacterial enzymes; the pattern (alpha, beta, gamma) helps differentiate species like Streptococcus.

Name one pigment-producing bacterium and its color.

Pseudomonas aeruginosa produces a green pigment (pyocyanin).

Why do we abbreviate many clinically common microbes (e.g., C. diff, MRSA)?

For convenience; their full binomial names are long and the abbreviations are widely recognized in clinical practice.

What is variolation?

The historical practice of intentionally infecting a person with smallpox material to induce immunity.

How did public exposure to "The Jungle" influence U.S. infectious disease rates?

It prompted food-safety regulations and inspection, reducing foodborne illnesses and overall infectious mortality.