Micro Lab Quiz 3

Question 1

TTC Deep

Answer 1

Triphenyl Tetrazolium Chloride

Question 2

TTC Deep is?

Answer 2

selective for olibgate aerobes and differential for motility (red/pink) E. coli (motile)

Question 3

TSI slant

Answer 3

Triple Sugar Iron agar (lactose, glucose, sucrose)

Question 4

TSI slant is?

Answer 4

non-selective, differential (enteric bacteria). black = H.S production, cracked agar = gas, pH indicator (phenol red, yellow = fermantation

Question 5

Tryptone Broth is?

Answer 5

non-selective, differential with kovac (Indole + E.coli), detects indole production, pink positive indole, yellow negative indole

Question 6

Bile esculin broth is?

Answer 6

selective and differential
Selective: bile salts inhibit streptococcus growth
Differential: tests abiity to hydrolyze esculin to grow clucose (black, enterococcus)

Question 7

MacConkey Agar is?

Answer 7

selective and differential
selective: crystal violet inhibits gram +, selects gram -
Differential: lactose with netural red dye; fermentors appear pink (E.coli) non (salmonella) coloress to yellow

Question 8

Ahbys nitrogen free agar

Answer 8

Selective for microbes that use atmospheric nitrogen for growth (nitrogen fixation)

Question 9

Tryptic soy agar and Luria Bertani

Answer 9

non selective, non differential

Question 10

CNA

Answer 10

Colistin-Nalidixic acid agar ( with blood)

Question 11

CNA is?

Answer 11

selective: gram +, colistin disrupts lipids and LPS in gram - outer membrane
Differential: blood detects differences in hemolytic activity

Question 12

Nalidixic acid (CNA)

Answer 12

quinolone targets gyrase for DNA replication

Question 13

Pseudomonas enrichment benzoate medium

Answer 13

Pseudomonas can convert hydroxybenzoate in the medium to Acetyl-CoA and succinate. used in TCA cycle

Question 14

PAF (Pseudomonas Agar F)

Answer 14

non-selective: differential: color change for pyoverdin (Fluoroscein) production
Green = P. aeruginose Yellow = P. fluorescens

Question 15

PAP (Pseudomonas Agar P)

Answer 15

non-selective, differential: color change for pyoxyanin production
Blue = P. aeruginosa

Question 16

MSA: Mannitol Salt Agar

Answer 16

selective: high salt selects for Staphylococcus
differential: mannitol fermnentation (yellow - acid)
Staphylococcus aereus = yellow, Staphylococcus epidermidis = red

Question 17

Blood Agar

Answer 17

differential: hemolytic activity, not considered selective
Beta hemolysis = complete (E. coli, S. aureus)
Alpha hemolyisis = partial, greenish (Streptococcus)
Gamma hemolysis = no hemolysis (S. epidermidis, enterococcus)

Question 18

DNase Agar

Answer 18

differential: violet/pink zone from DNase
DNase + (S. auereus)
DNase - (E. coli, S. epidermidis)

Question 19

Oxidase test

Answer 19

cytochrome oxidase (involved in electron transport)
oxidation of indicator - produces purple color
Pseudomonas, bacillus (+)
Escherichia, Staphylococcus , Enterococcus (-)

Question 20

Catalase test

Answer 20

hydrogen peroxide detects presence of catalase (Staphyloccocus, Azotobacter, E coli, BAcillus, serratia) (+)
(Streptococcus, enterococcus) (-)

Question 21

alfatoxins

Answer 21

carcinogenic compounds, flat-ringed planar compounds, intercalae between bases of DNA and act as mutagens
Produced by Aspergillus

Question 22

Myxobacteria

Answer 22

gram negative bacteria found in high-organic soils and in decomposing plant residues. Social bacteria

Question 23

Myxobacteria morphology

Answer 23

rod-shaped, flexible cell wall, flagella-independent gliding motility

Question 24

Myxobacteria ripples

Answer 24

groups of myxobacteria glide together on a solid surface, organize movement in form oc macroscopic traveling waves

Question 25

source of antibiotics?

Answer 25

Streptomyces members produce over 10,000 bioactive compounds

Question 26

photosynthesis

Answer 26

microbes capture light energy and convert to chemical energy

Question 27

Cyanobacteria

Answer 27

oxygenic photosynthesis, chlorophylls

Question 28

Green and purple bacteria

Answer 28

anoxygenic photosynthesis, bacteriochlorophylls, obligate anaerobes

Question 29

accessory pigments for photosynthetic bacteria

Answer 29

carotenoids, phycobiliproteins (absorb light energy of different wavelengths)

Question 30

purple nonsulfure are

Answer 30

facultative anaerobes (do not require oxygen but grow better with it)

Question 31

heterocysts

Answer 31

nitrogen fixing cells, anabaena

Question 32

Winogradsky column

Answer 32

illustration of how bacteria develop in certain habitats in response to appropriate enviromental conditions

Question 33

bacteria are commonly

Answer 33

autonomous, unicellular

Question 34

biofilm

Answer 34

many bacteria form multicellular, surface-attached communities called biofilms

Question 35

Biofilm formation stages

Answer 35

Attachment, colonization, maturation, and sipersal

Question 36

Attachment stage

Answer 36

individual bacteria transition from planktonic (free living) motile forms to adherent surface attached cells

Question 37

Colonization stage

Answer 37

attached cells will often lose their motility and synthesize and release polysaccharides, proteins, and DNA to formate a protective matrix

Question 38

The protective matrix

Answer 38

helps trap nutrients and provide protection from harmful agents, including antibiotics

Question 39

The matrix

Answer 39

helps to trap nutrients and provide protection from harmful agents

Question 40

quorum sensing

Answer 40

during colonization and maturation stages, bacteria sned and recieve chemical signals

Question 41

Dispersal stage

Answer 41

cells detach from biofil, regain motility, become planktonic