MICROBIO Lecture 1 Q&A FLASH

A set of question-and-answer flashcards covering foundational concepts, ecological roles, clinical relevance, and historical milestones introduced in the first microbiology lecture.

What is the difference between a microbe and a microorganism?

A microorganism is alive; a microbe may or may not be (e.g., viruses, prions are microbes but not organisms).

Name four major disciplines included within microbiology besides the study of microbes themselves.

Immunology, epidemiology, pathology, and clinical microbiology.

Roughly how long have microorganisms existed on Earth?

About 3.5 billion years.

Which ecological processes carried out by microbes are essential for human life?

Carbon recycling, conversion of CO₂ to O₂, nutrient cycling, and decomposition.

What does the root “kary” refer to in the word prokaryote?

Nucleus.

Why are prokaryotes considered more primitive than eukaryotes?

They lack a nucleus and other membrane-bound organelles.

What are the two domains of prokaryotes?

Bacteria and Archaea.

Why do microbiology courses focus on bacteria rather than Archaea?

Because no pathogenic Archaea have been found, whereas many bacteria cause preventable illness.

Which eukaryotic kingdom contains protozoans and algae?

Protista.

Why are protozoans clinically important?

They are the only protists that cause human disease (e.g., malaria, Giardia, Trichomonas).

Give two common properties of protozoans that make them ‘animal-like.’

Lack a cell wall and obtain nutrients by ingestion; many are motile.

What photosynthetic protist performs ~80 % of global CO₂→O₂ recycling?

Algae.

What environmental problem is intensified by excess CO₂ and involves rapid algal overgrowth?

Algal blooms (e.g., red tides).

Name two health hazards associated with algal blooms.

Depletion of oxygen killing marine life and proliferation of pathogenic bacteria that can infect swimmers.

Why are helminths only partially covered in this course?

They are macroscopic as adults, rare in developed countries, and only microscopic in larval stages.

What is an arthropod vector and give two disease examples it transmits.

An insect/arachnid that carries pathogens; examples: mosquitoes transmit malaria & dengue, ticks transmit Lyme disease & Rocky Mountain spotted fever.

Define an acellular infectious agent.

A biological entity lacking cellular structure and considered non-living, e.g., viruses, viroids, prions.

Why are viruses called obligate intracellular parasites?

They require a host cell to reproduce and carry out metabolism.

What two basic components make up a virus particle?

A protein capsid and a nucleic acid core (DNA or RNA).

How does a viroid differ from a virus?

Viroids consist solely of infectious RNA without a protein coat and infect plants, not animals.

What is a prion and what disease did it famously cause in cattle?

An infectious misfolded protein; causes bovine spongiform encephalopathy (mad cow disease).

State the basic food-safety rule derived from prion transmission studies.

Do not consume brains or lungs of animals to avoid prion diseases.

Name two human neurodegenerative disorders studied using prion models.

Dementia (e.g., Alzheimer’s) and Parkinson’s disease.

Give three pharmaceutical products originally derived from microbes.

Penicillin (fungus), streptomycin (bacterium), and statins (fungus).

Which 1970s discovery allowed production of human insulin in bacteria?

Recombinant DNA technology by Cohen and Boyer (1973).

What is bioremediation and give one engineered microbe used for it.

Use of organisms to clean pollutants; engineered Pseudomonas that digests crude oil.

Who is called the ‘Father of Microscopy’ and what magnification did his single-lens microscopes reach?

Antony van Leeuwenhoek; about 200× magnification.

What term did Leeuwenhoek use for the microorganisms he saw in pond water?

‘Animalcules.’

State Pasteur’s key experiment that disproved spontaneous generation.

The swan-neck flask experiment: boiled broth remained sterile until the flask neck was broken, showing life came from airborne microbes.

What is pasteurization?

Gentle heating (below boiling) of liquids for a set time to kill pathogens without altering product quality.

Describe Tyndallization (‘super-pasteurization’).

Multiple cycles of heating and cooling to destroy spores that survive single pasteurization cycles.

What are the first two tenets of modern cell theory proposed by Schwann & Schleiden?

1) All organisms are composed of one or more cells; 2) The cell is the basic unit of life.

Which scientist added the principle ‘all cells come from pre-existing cells’ to cell theory?

Rudolf Virchow.

List two additional modern extensions of cell theory.

Hereditary information is passed via DNA, and all cells share similar chemical composition/metabolic pathways (e.g., glycolysis).

What does Koch’s First Postulate state?

The suspected pathogen must be present in every case of the disease and absent from healthy organisms.

Why can’t Koch’s Postulates be applied to non-infectious diseases such as cancer?

Because they require a transmissible microbe (‘germ’) to satisfy isolation and re-infection criteria.

Which disease did Koch use to validate his postulates?

Anthrax (caused by Bacillus anthracis).

Name three microbiological tools or media developed in Koch’s laboratory.

Agar culture medium, Petri dishes, and pure-culture isolation techniques.

Who discovered lysozyme and later noticed a mold killing bacteria on a plate?

Alexander Fleming.

What fungus produces natural penicillin and on what spoiled item was it first seen?

Penicillium chrysogenum (initially Penicillium notatum) observed on a contaminated Petri dish.

Which two scientists mass-produced penicillin for WWII use?

Howard Florey and Ernst Chain (with Norman Heatley optimizing fermentation).

Define ‘super-infection’ in the context of WWII and penicillin.

Secondary bacterial infections of wounds that were treatable once penicillin became widely available, drastically reducing battlefield deaths.

Explain why algal blooms can lead to human infections such as Vibrio vulnificus.

Dead marine life under the bloom fosters pathogen growth; bacteria hitchhike on bloom material washed to shore, infecting swimmers through wounds.

Why should beachgoers avoid water with a visible red tide?

Red tide indicates dense algal/bacterial growth producing toxins and harboring pathogens, posing serious health risks.