Microscopy, Staining, and Classification

Question 1

General Principles of Microscopy -

1. Define Resolution

Answer 1

1. the shortest DISTANCE b/w two points on a specimen that can still be distinguished by the observer as separate entities

Question 2

General Principles of Microscopy -

1. Define Contrast
2. important in determining ___
3. ___ increases contrast

Answer 2

1. differences in INTENSITY b/w two objects, or between an object and background
2. resolution
3. staining

Question 3

Staining -

1. define
2. smear of microorganism (thin film) made prior to staining, must be fixed with ___

Answer 3

1. increases contrast and resolution by coloring specimens with stains/dyes
2. heat

Question 4

Staining -

1. List the 5 simple stain colors
2. List the three differential stains and what colors make up each

Answer 4

1. crystal violet, safranin (magenta red), methylene blue, malachite green, carbol fuchsin (bright red)
2. Gram Stain (crystal violet and safranin), Acid-Fast Stain (Carbol fuchsin and methylene blue), Endospore Stain (malachite green and safranin)

Question 5

Gram Stain -

1. ___ primary stain
2. decolorize (___l), explain
3. counterstain (___), explain
4. Results

Answer 5

1. crystal violet
2. alcohol, purple is washed from Gram (-) cells because walls are thinner
3. safranin, Gram (-) cells take on magenta/red color
4. Purple Gram (+) cells and Magenta/red (-) cells

Question 6

Mycobacteria -

1. what are they
2. their cell walls have a ___ content making them resistant to ___ by ___ during staining procedures such as the Gram stain
3. Referred to as “____”

Answer 6

1. a group of bacteria that do NOT have the typical peptidoglycan cell walls
2. high waxy mycolic acid content, decolorization, acids
3. acid-fast bacteria

Question 7

Acid-Fast Stain -

1. ____ primary stain
2. decolorize (___), explain
3. counterstain (___), explain
4. Results

Answer 7

1. carbol fuchsin
2. alcohol, acid-fast cells retain their red color because the acid cannot penetrate the waxy wall
3. methylene blue, stains only bleached, non-acid-fast cells
4. Red: acid-fast cells (microbacteria), Blue: non-acid-fast cells (everything else, including human cells and tissue)

Question 8

Endospore Stain -

1. ___ primary stain, use ___ to?
2. decolorize (___)
3. counterstain (___)
4. Results

Answer 8

1. malachite green, heat, drive into the endospore
2. water
3. safranin
4. green: endospores, magenta/red: vegetative cells

Question 9

What are the four groupings of bacteria?

Answer 9

1. Gram (+)
2. Gram (-)
3. Acid-Fast
4. Bacteria with NO cell wall

Question 10

Groupings of Bacteria -

1. Most Gram (+) bacteria end in (2)
2. Most gram (-) bacteria end in (2)
3. What is the difference bw/ acid fast and no cell wall?

Answer 10

1. -us or -um
2. -a or -er
3. acid fast HAS a cell wall

Question 11

____ has a fried egg appearance

Answer 11

mycoplasma

Question 12

Linnaeus -

1. system classified organisms based on ___
2. Used ___ (___)
3. proposed # kingdoms, list them

Answer 12

1. characteristics in common
2. binomial nomenclature, Genus species
3. 2. animals and plants

Question 13

Carl Woese -

1. compared nucleotide sequences of ___ subunits
2. proposed # domains as determined by ___, list them
3. cells in the three domains also ___

Answer 13

1. rRNA
2. 3, ribosomal nucleotide sequences, eukarya, bacteria and archaea
3. differ with respect to many other characteristics

Question 14

1. What are the five subunits of Eukarya (___)?
2. two subunits of Prokaryotes (___)
3. acellular = ___
4. what are helminthes?

Answer 14

1. cellular, animals, plants, fungi, protozoans, algae
2. cellular
3. viruses
4. worms

Question 15

Dichotomous Key -

1. What is this?
2. key directs user to another pair of statements or ___

Answer 15

1. series of paired statements where only one of two “either/or” choices applies to any particular organism
2. provides name of organism