Lab 3: Introduction to Staining Techniques

Question 1

Cocci

Answer 1

Spheres

Question 2

Bacilli

Answer 2

Rods

Question 3

Spirilla

Answer 3

Spirals

Question 4

Vibrios

Answer 4

Slightly curved rods

Variation of bacilli (rods)

Question 5

Coccobacilli

Answer 5

Short rods

Variation of bacilli (rods)

Question 6

Spirochetes

Answer 6

Flexible spirals

Variation of spirilla (spirals)

Question 7

Cell Arrangement

Answer 7

Determined by:
* The number of planes in which division occurs
* Whether the cells seperate after division

Is useful in identifying bacteria

Question 8

What is:

Rarely seen as anything other than singular cells?

Answer 8

Spirilla

Question 9

Which two morphologies form multicellular assocoations?

Answer 9

Cocci and Bacillus

Question 10

Which morphology exhibits the most variety in arrangements?

Answer 10

Cocci

Question 11

Diplococcus

Answer 11

Formed if two daughter cells remain attached after coccus divides

Question 12

Diplobacilli

Answer 12

Produced if the two daughter cells remain attached after bacilli divides

Question 13

Streptococcus and Streptobacillus

Answer 13

• Formed if the cells continue to divide in the same plane and remain attached
• Form a chain

Question 14

Cell Arrangement:

Single Cells

Answer 14

• Cocci
• Bacilli
• Spirilla
• Spirochetes
• Vibrios

Cell Morphology with the Cell Arrangement

Question 15

Cell Arrangement:

Pairs of cells

(“diplo-“)

Answer 15

• Cocci
• Bacilli

Cell Morphology with the Cell Arrangement

Question 16

Cell Arrangement:

Chains of cells

(“strepto-“)

Answer 16

• Cocci
• Bacilli

Cell Morphology with the Cell Arrangement

Question 17

Cell Arrangement:

Tetrads

Answer 17

• Cocci

Cell Morphology with the Cell Arrangement

Question 18

Cell Arrangement:

Cube

(sarcina)

Answer 18

• Cocci

Cell Morphology with the Cell Arrangement

Question 19

Cell Arrangement:

Irregular cluster

(“staphylo-)

Answer 19

• Cocci

Cell Morphology with the Cell Arrangement

Question 20

Cell Arrangement:

Palisade and angular

Answer 20

• Bacilli

Cell Morphology with the Cell Arrangement

Question 21

Tetrad

Answer 21

Occurs if second division occurs in a plane perpendicular to the first

Question 22

Sarcina

Answer 22

Produced when a third division plane perpendicular to the other two produces a cube-shaped arrangement of eight cells

Question 23

Staphylococcus

Answer 23

Produced if the division planes of a coccus are irregular
↓
A cluster of cells is produced

Question 24

Cells volume is made up of what?

Answer 24

Cytoplasm

Question 25

# Division patterns among cocci: Diplococci

Answer 25

Have a single divison plane *Generally occur in pairs*

Question 26

# Division patterns among cocci: Streptococci

Answer 26

Have a single division plane *Cells remain attached to form chains of variable length*

Question 27

# Division patterns among cocci: Tetrads

Answer 27

When there are two perpendicular division planes

Question 28

# Division patterns among cocci: Sarcina

Answer 28

Have divided in three perpendicular planes *produce a regular cuboidal arrangement of cells*

Question 29

# Division patterns among cocci: Staphylococi

Answer 29

Have divided in three planes *produce grapelike cluster of cells*

Question 30

# Cell Arrangment:

Answer 30

Diplococcus

Question 31

# Cell Arrangment:

Answer 31

Streptococcus

Question 32

# Cell Arrangment:

Answer 32

Tetrad

Question 33

# Cell Arrangment:

Answer 33

Sarcina

Question 34

# Cell Arrangment:

Answer 34

Staphylococcus

Question 35

Stains

Answer 35

Solutions consiting of a solvent (usually water or ethonol) and the chromogen

Question 36

Chromogen

Answer 36

* A colored molecule (often a benzene derivative) * May have multiple chromophores ↳ Each chromophore adding intensity to the color

Question 37

Chromophore

Answer 37

The portion of chromogen that gives color

Question 38

Auxochrome

Answer 38

The charged portion of a chromogen Allows it to act as a dye through ionic or covalent bonds between the chromogen and the cell

Question 39

Simple Staining

Answer 39

Used to identify and charecterize microorganisms based on: * Morpholology * Size * Arrangement

Question 40

Differential Staining | Differential - Structural Stains

Answer 40

Are used to identify specific charecteristics of microorganism: * Physical properties * Chemical properties

Question 41

# What kind of stains are all of the following: Methylene Blue Sarafin Crystal Violet

Answer 41

Simple (basic) stains

Question 42

Simple staining steps:

Answer 42

1. Create and heat fix smear on bacterial side 2. Cover slide with stain for 1 min. 3. Rinse with Distilled water 4. Blot dry with bibulous paper 5. View slide under microscope

Question 43

Negative Staining

Answer 43

Use of an **acidic stain** and, due to repulsion between the negative charges of the stain and the bacterial surface, the dye will **not** penetrate the cell

Question 44

Negative staining steps:

Answer 44

1. Add a drop of acidic stain on the edge of the slide 2. Using needle mix the culture sample with dye at the edge of the slide 3. Using second slide drag the mixture across the slide 4. Let air dry 5. View under microscope

Question 45

Gram Staining Technique

Answer 45

Differentiates based on bacterial cell wall

Question 46

Graim staining stains:

Answer 46

* Primary stain: **Crystal Violet** *stains both Gram (+) and Gram (-) cells purple* * Mordant: **Grams Iodine** *(forms crystal violet-iodine complex)* * Decolorizing Agent: **95% Ethanol** *(rinses off crystal violet and makes holes in gram (-) cell wall extracting the crystal violet)* * Counter Stain: **Safranin** *stains the Gram (-) cell wall pink/red*

Question 47

Gram Staining procedure:

Answer 47

1. Begin with heat-fixed slide 2. Cover with **Crystal Violet** for 1 minute 3. Rinse with **DH2O** 4. Coverwith **Gram Iodine** for 1 minute 5. Rinse with **DH2O** 6. Rinse with **95% Ethanol** to decolorize 7. As soon as runoff is clear, IMMEDIATELY rinse with **DH2O** 8. Counterstain with **Safranin** for 1 minute 9. Rinse with **DH2O** 10. Blot dry with bibulous paper

Question 47

Answer 47

Gram Stain

Question 47

Answer 47

Gram Negative

Question 47

Answer 47

Gram Positive