Staining and Imaging Techniques, Bacterial Growth

Question 1

Name 3 examples of basic dyes

Answer 1

crystal violet, methylene blue, safranin

Question 2

Name 2 examples of acidic dyes

Answer 2

eosin, india ink

Question 3

What is a disadvantage to using a simple stain?

Answer 3

Doesn’t indicate size of an organism because it shrinks during the procedure

Question 4

What staining process first applies basic dye, then wash it out with iodine and alcohol/acetone, and then add a counterstain?

Answer 4

gram stain, which is a differential stain

Question 5

A pink stain demonstrates _____ ______ bacteria

Answer 5

gram negative, stained with safranin

Question 6

What is a special/structural stain?

Answer 6

Identifies structures within or on cells, and different parts of cells are stained different colors. Example: endopores in some gram positive bacteria (bacillus, clostridium)

Question 7

Name three examples of special stains

Answer 7

negative (capsule) stain, flagellar stain, flourescent stains

Question 8

What kind of stain is best in finding true size of an organism?

Answer 8

Negative stain (acidic dye used, not fixed with heat so no shrinkage)

Question 9

What stain type uses carbol fuschin and heat? What specific cell wall structure is involved in this stain? What kind of bodily fluid is used for this stain, and what kind of bacterial infection are you testing for?

Answer 9

1. Acid-fast stain.
2. Mycolic acid (lipid) in the cell walls need heat to loosen the cell wall so the carbol fuschin can penetrate for staining.
3. Sputum smear is used to test for Tuberculosis

Question 10

Malachite green, heat, and safranin are used for what kind of staining technique?

Answer 10

Endospore stain

Question 11

What is unique about a parfocal microscope?

Answer 11

Can change magnifications without losing focus of organism

Question 12

Ability to distinguish 2 objects as separate/distinct is called_____.
What kind of lens helps increase this property?

Answer 12

1. Resolution

2. Oil immersion lens

Question 13

Closest distance two things can be together and still be seen as separate is called____

Answer 13

resolving power
RP=wavelength of light/(2 x numberical aperture)
Refractive index of material between objective lens & specimen

Question 14

Name two kinds of electron microscopes

Answer 14

1. transmission electron microscope

2. scannng electron microscope

Question 15

Name 5 physical requirements for bacterial growth

Answer 15

Temperature
Oxygen
pH
Osmolarity
Pressure

Question 16

What can maintain life via fermentation or anaerobic respiration or by aerobic respiration?

Answer 16

facultative anaerobe

Question 17

What does not use aerobic metabolism, and oxygen is not toxic to them (have enzymes)

Answer 17

aerotolerant anaerobes

Question 18

What organisms require 2-10% of oxygen?

Answer 18

microaerophiles

Question 19

Which microbes (based on temperature range) cause disease in humans since they are at body temperature?

Answer 19

MESOphiles

Question 20

Name three classifications of bacteria based on pH growth factors. Which organisms grow best in which classification?

Answer 20

1-neutrophiles (6.5-7.5 pH)- bacteria and protozoa
2-acidophile (grow best in acidic habitats)- other bacteria and fungi
3-alkalinophiles (live in alkaline soils/water up to 11.5 pH)

Question 21

a solution with lower solute concentrations will lead to the cell swelling and bursting. this is in _________ state

Answer 21

hypotonic

Question 22

a solution with higher solute concentration will lead to plasmolysis (shriveling of cytoplasm)t. this is in ____________state

Answer 22

hypertonic

Question 23

________ grow in up to 30% salt. __________ can tolerate high salt concentrations (give an example)

Answer 23

1-obligate halophiles

2-facultative halophiles- example is staph

Question 24

organisms that live under extreme pressure to maintain their 3-d and functional shape are called ______________

Answer 24

barophiles

Question 25

Describe the four phases of microbial growth

Answer 25

1. Lag phase-Organisms are acclimating
2. Log phase-Logarithmic increase in cell number
3. Stationary phase-Nutrients depleting, waste accumulating (Growth = dividing cells)
4. Death phase- Dying > dividing