The Microbial World and You

Introductory flashcards covering the basics of microbiology, including microbial groups, roles in the environment, pathogenicity, historical milestones, and emerging infectious diseases.

What is the definition of a microbe (microorganism)?

An organism that is too small to be seen with the unaided eye.

What are the four major groups of microbes?

Bacteria, Viruses, Fungi, and Parasites.

What are the two groups of microbes that serve as decomposers of organic wastes?

Bacteria and fungi.

Which microbes are responsible for photosynthesis and what is the benefit to humans?

Bacteria (Cyanobacteria) and protozoa (Algae); they benefit humans by producing oxygen.

What is the process of Nitrogen ($N_2$) Fixation?

The process by which bacteria capture free atmospheric Nitrogen ($N_2$) and convert it into nitrates used by plants for development.

How is bioremediation defined in the context of microbiology?

The non-natural, artificial process where microbes are used to remove pollutants or toxic wastes from the environment.

What are two specific examples of bioremediation using bacteria?

1. Using bacteria to remove toxic substances from oil spills in the ocean. 2. Using bacterial enzymes in drain cleaners to remove clogs.

What are some commercial uses for bacteria?

Production of dairy products (cheese, yogurt) and cosmetic procedures (Botox).

What commercial products are produced using fungi (yeast)?

Alcoholic beverages (wine, beer) and breads.

What are two examples of microbes used to produce antibiotics in medicine?

Penicillin and Neomycin.

What percentage of bacteria are considered harmful (pathogenic)?

Less than $1\%$ ($< 1\%$).

What is a pathogen?

A live agent capable of causing disease (harm) in a host.

Match the following pathogens to their diseases: Neisseria gonorrhoeae, Tinea pedis, and SARS-CoV-2.

Neisseria gonorrhoeae causes Gonorrhea; Tinea pedis causes Athlete’s foot; SARS-CoV-2 causes COVID-19.

What are normal microbiota (normal flora)?

Resident microbes found inside and outside the human body that cause no harm and may provide benefits.

What are two benefits provided to humans by normal microbiota?

1. Producing useful substances like vitamin K. 2. Preventing the overgrowth of harmful microbes.

Which scientist was the first to observe live microorganisms through magnifying lenses?

Anton van Leeuwenhoek.

What was Edward Jenner's major contribution to microbiology?

He developed the first vaccine (against Smallpox) by observing that milkmaids infected with Cowpox Virus were protected from Smallpox.

What is the Theory of Biogenesis established by Louis Pasteur?

The theory that living cells arise only from pre-existing living cells.

How did Louis Pasteur disprove the theory of Spontaneous Generation?

He used S-shaped flasks to show that boiled beef broth remained free of microorganisms because the bend in the flask neck prevented microbes from entering.

What was Joseph Lister’s contribution to medical procedures?

He began using chemical solutions (antiseptics) to treat surgical wounds and kill microbes, which reduced surgical infections and deaths.

What did Robert Koch establish regarding the cause of infectious diseases?

He established the Germ Theory, which states that infectious diseases are caused by live pathogens.

What are Koch’s Postulates?

A sequence of experimental steps used to relate a specific microbe to a specific disease with specific symptoms.

What concept did Paul Ehrlich develop and what term did he coin?

He developed the concept of chemotherapy and coined the term "magic bullet" to describe a chemical that targets a pathogen without harming the host.

Who discovered the first antibiotic, Penicillin?

Alexander Fleming.

What discovery did Barry Marshall make regarding peptic ulcers?

He proved that most peptic ulcers were caused by the bacterium Helicobacter pylori.

What are Emerging Infectious Diseases (EIDs)?

Diseases that are new or changing and are increasing, or have the potential to increase, in frequency in the near future.

Identify four factors that contribute to the emergence of EIDs.

Global travel, rapid urbanization, natural disasters, climate change, frequent gene mutations, and developing drug resistance.