History of Microbiology and Microscopy (Lec. 2)

Question 1

Define cell theory

Answer 1

All living organisms are composed of cells, which are the basic structural and functional units of life, and all cells arise from pre-existing cells.

Question 2

Define spontaneous generation

Answer 2

The now-disproven theory that living organisms can arise from non-living matter

Question 3

Define biogenesis

Answer 3

The hypothesis that living matter only arises from other living matter

Question 4

Define fermentation

Answer 4

The process in which a substance breaks down into a simpler substance (microorganisms usually play a role)

Question 5

Define pasteurization

Answer 5

The partial sterilization of a product, such as milk or wine, to make it safe for consumption and improve its keeping quality.

Question 6

Identify the contributions to science made by Hooke

Answer 6

Cell theory

Question 7

Identify the contributions to science made by van Leeuwenhoek?

Answer 7

Built his own simple microscopes, first to see bacteria

Question 8

Identify the contributions to science made by Pasteur?

Answer 8

Invented pasteurization method, refuted spontaneous generation of animalcules, came up with germ theory of disease and biogenesis, developed rabies and anthrax vaccines.

Question 9

Identify the contributions to science made by Koch

Answer 9

Confirmed germ theory, identified causative agent of anthrax, came up with koch’s postulates

Question 10

Identify the contributions to science made by Linnaeus

Answer 10

Developed taxonomic naming system for organisms

Question 11

Identify the contributions to science made by Woese

Answer 11

Discovered Archaea

Question 12

Identify the contributions to science made by Fleming

Answer 12

Determined that mold excreted a compound that could inhibit bacteria (penicillin)

Question 13

Describe Pasteur’s experiment that disproved spontaneous generation

Answer 13

He boiled beef broth in a swan-necked flask, which allowed air to enter but not dust or other particles. Over time, no new microorganisms grew in the broth, demonstrating that life did not spontaneously generate from non-living matter

Question 14

List Koch’s postulates of disease

Answer 14

1. The same organism must be present in every case of the disease but not present in healthy individuals
2. The organism must be isolated from the diseased host and grown as a pure culture.
3. The isolated organism should cause the disease in question when it is inoculated into a susceptible host
4. The organism must then be re-isolated from the inoculated, diseased animal.

Question 15

Identify the type of microscopy used to generate a given image: slide 18 lecture 2

Answer 15

bright-field, phase-contrast, dark-field, or differential interference contrast (DIC)

Question 16

Compare and contrast different types of light microscopy

Answer 16

Two sets of lenses form the image. Phase contrast is used to see inside things when they’re alive. Things can be alive or dead for fluorescence microscopy. Bright field microscopy has a bright background (resolution is less but more defined edges). Dark field microscopy has a dark background (disadvantage: very sensitive to dust).

Question 17

Compare and contrast light microscopy vs. CSLM vs. EM

Answer 17

Light microscopy uses visible light to magnify and image specimens. Confocal scanning laser microscopy uses a computerized fluorescence microscope coupled with a laser source to generate a 3D image. Electron microscopy uses electrons instead of photons, and electromagnets function as lenses.

Question 18

Compare and contrast TEM vs. SEM

Answer 18

Transmission electron microscopy: specimen must be very thin and is stained with high atomic weight substances that scatter electrons well; the electrons penetrate through it and produce an image of internal structures. Scanning electron microscopy: specimen is coated with a thin film of heavy metal, and scattered electrons are collected and projected to produce an image of the surface of the specimen.