Microbiology Study Questions

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I. INTRODUCTION

Independent Study Questions
1.) What is the fundamental difference between eukaryotic and prokaryotic cells? Procaryotic cells do not contain a membrane-bound nucleus or any membrane-bound organelles. Eurkaryotic cells contain both a membrane mound nucleus and membrane-bound organelles (making them far more complex).

2.) List and describe the two domains of prokaryotic organisms. a. Bacteria- Most are a specific shape (cylindrical, spiral, or spherical). Cell wall contains peptidoglycan. Multiply by binary fission. b. Archaea- Similar in shape, size, and appearance to Bacteria. Multiply by binary fission. Cell wall does not contain peptidoglycan.

3.) List and describe the four groups of eukaryotic microorganisms c. Algae – diverse group of photosynthetis eukaryotes that often live in aqueous environments. Some are single-celled, while others a multi-celled. They all contain chloroplasts. Have a rigid cell wall. Most move by mean of flagella. d. Fungi – Yeasts, molds, and mushrooms. Some are single celled but many are large, multicellular ogranisms. Live primarily on land. e. Protozoa – single-celled eukaryotes that are not algae or fungi. Found in both terrestrial and aquatic environments. Do not have a rigid cell wall. f. Multicellular paracites (worms) – Live at the expense of a host

4.) List and describe the 3 types of non-living infectious agents g. Viruses – Nucleic acid 9DNA or RNA) surrounded by a protein coat. Multiply by using the machinery and nutrients of living cells. h. Viroids – Consist of only a single, short piece of ribonucleic acid. Like viruses, they multiply only inside cells. They cause a number of diseases in plants. i. Prions – Misfolded (abnormal) various of a normal cellular protein. When it contacts the normal protein, it causes the normal protein to misfold. Cell becomes filled with misfolded protein that all bind together to form fibrils (thread-like structures). Fibril-filled cells are not able to function. Responsible for several fatal neurodegenerative diseases. More resistant to degradation by enzymes than the normal forms are.

5.) What are prions?
See above.

6.) In the name Bacillus anthracis – which part indicates the genus and which part indicates the species? Bacillus indicates the genus and anthracis indicates the species. 7.) Which is most closely related – organisms in the same genus or organisms in the same species? Organisms in the same species are more closely related.

Review Question
1.) Describe the general reasons why microbiology is important

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II. MICROSCOPY AND CELL STRUCTURE

Independent Study Questions
1.) What is an advantage of an electron microscope over a light microscope, and vice versa? An advantage of the electron microscope is that it has a max. magnification of ~100,000X while a light microscope only has a maximum magnification of ~1,000X. One drawback of the electron microscope (vs. a light microscope) is that the specimen and the lenses both must be in a vacuum (otherwise air molecules would interfere w/ the path of electrons). Thus this results in an expensive and bulky microscope and complex specimen preparation. This also means that electron microscopes can’t be used to observe the activities of living cells.

2.) How is a differential stain different from a simple stain? In a simple stain uses only a single dye. In a differential stain first uses a primary stain (which generally stains all cells). After rinsing the excess dye, applying Gram’s iodine and applying a decolorizing agent (that removes the dye-iodine complex from Gram-negative, but not Gram positive cells), a counterstain is applied to give a different color to the now-colorless Gram-negative bacteria.

3.) What does a Gram-positive cell look like? How about a Gram-negative cell? A...
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