Microbiology Lab Exam

Front 1

Ocular lens

Back 1

10x

Front 2

Magnification

Back 2

Ocular lens X objective lens

Front 3

What do you do before putting immersion lens in place?

Back 3

Place a drop of immersion oil onto the specimen on the slide

Front 4

Shape of bacteria

Back 4

Bacillus, coccus, coccobacillus

Front 5

Endospore bacteria

Back 5

Bacillus, clostridium, sporosarcina

Front 6

Purpose of acid fast stain

Back 6

To differentiate between bacteria containing waxy mycolic acid in their cell wall such as Mycobacterium and Nocardia

Front 7

What is the bacterial cell wall composed of

Back 7

Peptidoglycan which is abundant in gram-positive cells but limited in gram-negative cell which is mostly lipid do to outer membrane

Front 8

Dyes of simple stain

Back 8

Crystal Violet, methylene blue, safranin, malachite green

Front 9

What must be done before heat fixing?

Back 9

Slide must air dry

Front 10

Bacterial capsules are composed

Back 10

Mucoid polysaccharides or polypeptides

Front 11

Why are agar plates inoculated upside down?

Back 11

To prevent any condensation that might form and drip onto the agar surface, resulting in the movement of organisms between colonies

Front 12

Examples of Bunsen burner uses

Back 12

To hit fix slides and to sterilize test tube lips, needles and loops

Front 13

Phenotypes of fungus

Back 13

Color, size, shape, and appearance between species

Front 14

Differentiate between hyphae and mycelium

Back 14

Hyphae are the filamentous bodies which make up the mycelium whereas mycelium is a mass of hyphae

Front 15

Why are Loops flame before and after inoculation

Back 15

To sterilize them of any contaminants and bacteria that is on its surface

Front 16

What is a colony

Back 16

A large number of bacterial cells on a solid medium normally originated from one parent cell

Front 17

Purpose of heat fixing

Back 17

Kills bacteria in the smear, firmly and adheres the smear to slide, and allows the sample to more readily take up stains

Front 18

Problems with heat fixing

Back 18

Overheating can damage and dehydrate the cells causing them to distort and shape and also the slide can crack or shatter

Front 19

Function of a mordant

Back 19

To hold down molecules of a stain onto a microorganism

Front 20

Mycobacteria

Back 20

Causes tuberculosis and leprosy

Front 21

Virulence of of mycobacteria

Back 21

Linked to its mode of transmission. Tuberculosis is spread through the air, which can be easily inhaled and leprosy through the contact with infected person

Front 22

Differentiation of stains

Back 22

Stains that allowed one to see the differences between bacterial cells. Gram stain, acid fast stain, endospore stains are all differentiation stains

Front 23

Structure of flagella

Back 23

Basal body, hook, filament

Front 24

Filament (flagella)

Back 24

Outer most region

Front 25

Hook ( flagella)

Back 25

Attaches to the filament

Front 26

Basal body (flagella)

Back 26

Consists of rods and pairs of rings, adheres flagella to the cell wall and membrane

Front 27

How does flagella generate motility

Back 27

Flagella rotate counter-clockwise to propel the cell forward and clockwise to Tumble and change direction

Front 28

True motility

Back 28

Movement in all directions

Front 29

Brownian motility

Back 29

Vibrational movement

Front 30

Water current motility

Back 30

Movement in the same direction (looks like a sweeping motion)

Front 31

Endospore

Back 31

Metabolically inactive structure within certain genus of bacteria that function to protect the genetic information during harsh conditions; resistant to chemical, heat destruction and destruction by radiation

Front 32

Mycoplasm

Back 32

Causes walking disease, lack cell wall, sterols in plasma membrane, resistant to many common antibiotics

Front 33

Gram Stain

Back 33

1. Make smear, air dry, and heat fix

2. Crystal violet for 20 seconds

3. H2O wash

4. Iodine for 1 minute

5. Decolorize with 95% alcohol for 10 seconds

6. H2O wash

7. Counterstain with safranin for 1 minute

8. H2O wash and blot dry

Front 34

Acid fast stain

Back 34

1. Make a smear, air-dry, heat fix

2. Place paper towel over slide and saturated with carbol fuchsin.

3. Place slide over breaker with boiling water for 5 - 10 minutes. Do not allow slide to dry out

4. Cool and rinse with H2O

5. Decolorize with acid alcohol for 1 minute

6. Counter stained with methylene blue for 1 minute

7. H2O wash and blot-dry

Front 35

Spore Stain

Back 35

1. Creates smear, air-dry, heat fix

2. Place paper towel over smear and saturated with malachite green

3. Steam over Beaker with boiling water for 5 to 10 minutes without allowing paper towel to dry out.

4. H2O rinse

5. Counterstain with safranin for 1 minute

6. H2O rent and blot dry

Front 36

Staphylococcus aureus

Back 36

Gram positive, cocci bracteria

Front 37

Mycobacterium smegmatis

Back 37

Acid fast, bacillus

Front 38

Pseudomonas aeruginosa

Back 38

Encapsulated, gram negative, rods

Front 39

Escherichia coli

Back 39

Gram negative, rods, encapsulated

Front 40

Serratia marcescens

Back 40

Rods, gram negative

Front 41

Proteus vulgeris

Back 41

Rod, gram negative

Front 42

Bacillus megaterium

Back 42

Rods, gram positive, spore forming

Front 43

Micrococcus letus

Back 43

Gram positive cocci

Front 44

Gram positive rod shaped bacteria

Back 44

Bacillus magaterium

Front 45

Gram positive cocci bacteria

Back 45

Micrococcus letus

Staphylococcus aureus

Front 46

Gram negative rod shaped bacteria

Back 46

Proteus vulgeris

Serratia marcescens

Escherichia coli

Pseudomonas aeruginosa

Front 47

Acid Fast rod bacteria

Back 47

Mycobacterium smegmatis

Front 48

Streptococcus pneumoniae

Back 48

A gram positive bacteria that causes the majority of community acquired pneumonia