Microbiology Exam 1 Chapters 1-5

What is the study of biology concerning organisms too small to see without magnification?

Microbiology

What is the approximate size of a prion?

10 nanometers

What is the approximate size of an archeon?

100 nanometers

What is the approximate size of a bacterium?

1 micrometer (or 1000 nanometers)

In what unit of measurement is the size of a virus usually expressed?

Nanometers

What is the approximate size of a eukaryote cell?

10 micrometers

Are all eukaryotes considered microorganisms?

No, because some eukaryotes like fungi and humans are large.

In early history, disease was often superstitiously viewed as a curse from God, such as in the case of _____.

Leprosy

What early method was used to control disease transmission without knowing the actual cause?

Burning bedding and houses

A microbe that causes disease is called a?

Pathogen

A microbe that usually doesn’t cause trouble is called a

Normal microbiota

What is a microbe that causes disease only under specific conditions, such as a weakened immune system.

Opportunistic pathogen

Which type of disease outbreak is widespread in a local community at a specific time, often with surprise spikes?

Epidemic

How does a pandemic differ from an epidemic?

A pandemic spreads across entire continents.

What term describes a disease regularly found at certain intervals with predictable occurrences?

Endemic

Term: Emerging disease

Definition: A disease appearing for the first time, such as COVID-19.

Term: Re-emerging disease

Definition: A disease that was previously a major issue and is becoming a problem again, such as tuberculosis.

In the Woese-Fox system, which two domains are predominantly single-celled and lack a true nucleus?

Bacteria and Archaea

How much smaller are Bacteria and Archaea compared to Eukarya?

Up to 10 times smaller

What are the two defining structural characteristics of Eukarya cells compared to prokaryotes?

A true nucleus and organelles

Which scientist developed a microscope that made examining household objects easier?

Robert Hooke

Who is known as the "Father of Microbiology" for observing microbes in drops of water?

Antoine van Leeuwenhoek

In Pasteur's flask experiment, where did the microbes grow when the broth was exposed to air?

Only where the neck of the flask was broken

According to Pasteur, what two environmental factors caused microbes to form in the broth?

Air and dust

What is the name of the theory Pasteur supported by showing yeast fermented beet sugar?

Germ theory

What process involves heating foods to kill bacteria without altering their nutritional value?

Pasteurization

Which doctor established the practice of handwashing to lower blood poisoning in maternity patients?

Ignaz Semmelweis

Which scientist used phenol as an antiseptic in surgery?

Joseph Lister

Term: Antiseptic

Definition: A substance or state free from disease-causing pathogens.

Term: Sterile

Definition: A state free of all life forms.

What are the two primary agents used to achieve sterilization?

Heat or chemicals

Who determined that cholera in London was transmitted through the water supply?

John Snow

What analytical method did John Snow use to track the cholera outbreak?

Geospatial or statistical analysis

According to Koch's postulates, where must the suspected microbe be found?

In all sick organisms and absent from healthy ones.

What is the second step of Koch's postulates regarding the microbe from a sick host?

It must be isolated and grown in a pure culture.

In Koch's postulates, what happens when a healthy animal is infected with the pure culture?

It must develop the same disease.

What is the final step of Koch's postulates?

The same microbe must be re-isolated in pure culture from the newly infected host.

Why were the diseases discovered by Buist and Beijerinck unique?

They were viral diseases that would not grow on agar.

Which scientist discovered the tobacco mosaic virus?

Martinus Beijerinck

What did Girolamo Fracastoro identify regarding disease?

Contagion particles and methods of transmission

Which scientist identified bacteria in the tissue of leprosy patients?

Gerhard Hansen

Who used cowpox to create a vaccine against smallpox?

Edward Jenner

Macrobiology Class: Carbohydrates

Example: Simple sugars like glucose.

Macrobiology Class: Lipids

Example: Fats like triglycerides.

Macrobiology Class: Proteins

Example: Amino acids and enzymes.

Macrobiology Class: Nucleic acids

Example: DNA.

What are the three components of a nucleotide?

Pentose sugar, nitrogen base, and phosphate.

Term: Nomenclature

Definition: The system for naming organisms.

Term: Taxonomy

Definition: The science of naming, identifying, and classifying organisms.

How does molecular classification differ from traditional classification?

It uses DNA and RNA for higher precision rather than just appearance and structure.

Which scientist developed salvarsan to treat syphilis?

Paul Ehrlich

What did Alexander Fleming discover in penicillium mold?

It could kill bacteria, leading to the development of penicillin.

List the "Five I's" of microbiology in order.

Inoculation, Incubation, Isolation, Inspection, and Identification.

What occurs during the inoculation phase?

Microbes are placed into a medium of growth, such as broth or agar.

What is the primary purpose of the incubation phase?

To mimic human body temperature to encourage microbe growth.

Atmospheric conditions during incubation may require the addition of which two gases?

oxygenor carbon dioxide

What three items are required for the isolation phase?

A firm surface (agar), a Petri dish, and an inoculating loop.

The _____ plate method is used to separate cells and grow discrete mounds called colonies.

Streak

Term: Colony

Definition: A discrete mound of cells on an agar plate.

How long should one typically wait for microbes to grow before the inspection phase?

24 hours

During identification, what is a common test used to determine how to treat a pathogen?

Susceptibility testing

What are the four physical states of media?

Liquid, semisolid, solid (liquefiable), and solid (non-liquefiable).

From what source is agar derived?

Sea plants

Term: Selective media

Definition: Media containing agents that inhibit the growth of specific unwanted microbes.

Term: Differential media

Definition: Media that allows multiple microbes to grow but displays differences in their appearance.

Can a single growth medium be both selective and differential?

Yes.

Which scientist improved light microscopy and developed oil immersion?

Robert Koch

Term: Resolution

Definition: The ability to distinguish between two adjacent objects.

Term: Contrast

Definition: The difference in brightness between objects or between an object and its background.

What is the name of the initial image created by the objective lens?

Real image (or intermediate image).

What is the name of the magnified impression formed by the ocular lens?

Virtual image

What is the total magnification achieved with oil immersion?

1000x

Which microscope type passes light through a dead, stained specimen?

Bright-field

Which microscope type uses light directed from the sides to show a dark background?

Dark-field

What is phase-contrast microscopy specifically good for observing?

Internal cell movement in thin subjects.

Which microscope type utilizes a focused beam of electrons to provide a 3D view of a surface?

Scanning tunneling electron microscope

Which microscope type sends electrons through a subject to visualize internal structure?

Transmission electron microscope

Term: Simple stain

Definition: A staining technique where all specimens are colored the same single color.

Term: Special stain

Definition: A stain used to highlight specific structures of a microbe.

What is the first step in the Gram stain procedure?

Staining with crystal violet.

What is the purpose of the alcohol wash in a Gram stain?

It acts as a decolorizer.

Which counterstain is used in the Gram stain process?

Safranin

What color do Gram-positive bacteria appear after staining?

Violet or blue

Why do Gram-positive bacteria retain the crystal violet stain?

They have more peptidoglycan in their cell walls.

What color do Gram-negative bacteria appear after staining?

Orange-red

What specific component of microbacteria does the Acid-fast stain identify?

Waxy mycolic acids

In an Acid-fast stain, what color do positive cells turn?

Red

What is the primary stain used to detect bacterial endospores?

Malachite green

How do endospores appear in a spore stain compared to the rest of the cell?

Green spores against pink cells.

According to the source, what is a capsule stain used to show using a mordant?

Flagella

Which staining method shows high-contrast cellular structures under UV light?

Fluorescence stain