Micro Exam #1

Covers "Welcome to Microbiology," "Microscopy"

What is a microbe?

A broad term; cannot be seen with the naked eye. Includes viruses and requires a microscope to be seen

What is a microorganism?

Doesn’t include acellular entities (like viruses)

What are the 3 classification schemes?

Bacteria, Eukarya, and Archaea

True or False: Viruses do not belong in any of the domains.

True

True or false: RNA is used to classify the domains.

True

Where can you find microbes?

Domain bacteria: all microbes

Domain Archaea: all microbes

Domain Eukarya: Kingdom Fungi, Kingdom Protista, Kingdom Animalia

What are the kinds of acellular entities?

Viruses, viroids, satellites, and prions

Who built the first microscope and coined the term “cell”?

Robert Hooke

Who was the first to observe single-celled microbes that he called “small animals”?

Antonie van Leeuwenhoek

Who created the first vaccine?

Edward Jenner

What is smallpox?

A viral infection characterized by skin lesions, and once infected, victims had worse skin lesions on sebaceous oil glands

True or false: 30% (1 of 3) of people who were infected from smallpox died.

True

True or false: Young adults were more likely to die from smallpox.

False; it was young children and older adults most affected

How did Jenner create the first vaccine?

He noticed female patients weren’t contracting/dying from smallpox, and he studied the lives of these patients. He found out that all of them were cow maids who contracted cowpox, and thus gave them immunity to smallpox

What is cowpox?

Mild smallpox acting on teats of cows. Its contagious to humans and causes small fever, mild skin lesions. Contracted from milking cows.

What does “Vacca” mean in latin?

Cow

True or False: Smallpox treatment caused mass eradication of the disease.

True

True or false: Edward Jenner is the father of vaccines.

False; he is the father of immunoscience

What decade was germ theory developed?

The 1850s

Who proved wrong the spontaneous generation theory?

Louis Pasteur

Who developed a system of antiseptics to precent microorganisms from entering wounds (which turned out successful and transformed surgery)?

English surgeon Joseph Lister

What are Koch’s Postulates?

Criteria for proving a relationship between a microbe and a specific disease

What are the 4 Koch Postulates?

1.Microbes must be present in every case of the disease by absent form of a healthy organism

2.Suspected microbes must be isolated and grown in pure culture

3.Same disease must result when isolated microbes are inoculated into a healthy host

4.Some microbes must be isolated again from diseased host

Sometimes Koch’s Principles are not possible. What are a few reasons that the postulates wouldn’t apply?

Not being able to isolate in pure culture, can’t be cultured, no animal model, and more than one microbe causing the disease

What are the three main breakthroughs in microbiology?

1.Being able to see microbes using microscopes

2.Being able to grow/study microbes using sterile media

3.Microbiome - refers to collection of genomes from all the microorganisms in a given environment

What are the four types of microscopy?

Bright-Field, Dark-Field, Phase contrast, and fluorescence

What is total magnification?

Objective mag x ocular mag

How do you prepare a specimen?

By using wet mount preparation, which you place microbes in a drop of water on a slide with a coverslip.

What are the advantages and disadvantages in wet mount preparation?

Advantages are that you can observe cells in natural state and disadvantages are that there is little contrast between cell and background, and also that the sample may dry out quickly

What is fixation?

When cells are made to adhere to a slide in a fixed position

What is staining?

When cells are given distinct color and creates contrast

What are the two differential stains used in microbiology?

Acid-fast and spore stain

What is acid-fast staining?

Carbolfuchsin used to stain mycobacterium species

What is spore stain?

It is a malachite green color used to detect spores of bacillus and clostridium

True or False: Endospores are survival structures.

True

What is dark field microscopy?

It detects very narrow cells that are unresolved by bright field microscopy

What is phase contrast?

It exploits differences in refractive index (shows more detail)

What is excitation and emission?

Specimen absorbs light of specific wavelength (excitation), then emits light at a longer wavelength (emission)

What is fluorescence microscopy?

When a specimen absorbs light of a defined wavelength, and then emits light of lower energy, thus longer wavelength; that is, the specimen fluoresces.

What is biofilm?

A community of microbes

What is scanning electron microscopy (SEM)?

When electrons scan the surface of the specimen and reveal external features in 3D. Specimens are also coated in heavy metals and electron beam scans the object, causing scattered electrons collecting by a detector and produce an image

What is transmission electron microscopy (TEM)?

When electrons pass through a specimen and reveals the internal structures. The electromagnetic function as lenses and has high magnification. The specimen must be cut in thin slices and be stained