Lab Quiz 9: Gram Positive Cocci Biochemistry, Microbial Symbioses, and Wastewater Treatment (Bio 286 - Microbiology)

Question 1

mannitol salt agar

Answer 1

selective and differential media; contains 6.5% NaCl, phenol red dye, and mannitol…. microbes that are able to grow may ferment mannitol or not (if they do, the acids they produce turn the indicator dyes in the media yellow)

Question 2

mannitol salt agar (MSA) growth positive result

Answer 2

GROWTH

Question 3

mannitol salt agar (MSA) growth negative result

Answer 3

no growth

Question 4

mannitol salt agar (MSA) fermentation negative result

Answer 4

red

Question 5

mannitol salt agar (MSA) fermentation positive result

Answer 5

YELLOW

Question 6

catalase

Answer 6

enzyme that decomposes hydrogen peroxide to water and oxygen gas– when H2O2 is placed on the microbes, the production of bubbles indicates a positive reaction

Question 7

catalase (H2O2) negative result

Answer 7

no bubbles

Question 8

catalase (H2O2) positive result

Answer 8

BUBBLES

Question 9

EF broth

Answer 9

media containing a fermentable sugar (glucose) and an acid indicator (bromcresol purple)– glucose fermentation results in acid end products, which cause the media to turn yellow… the media also contains a metabolic poison sodium azide, allowing only azide-resistant microbes to grow

Question 10

EF broth negative result

Answer 10

purple

Question 11

EF broth positive result

Answer 11

YELLOW

Question 12

NaCl broth

Answer 12

contains 6.5% NaCl, allowing only halotolerant microbes to grow and turn the media cloudy

Question 13

NaCl broth negative result

Answer 13

clear

Question 14

NaCl broth positive result

Answer 14

CLOUDY

Question 15

bile esculin slant

Answer 15

media used to detect the metabolism of a compound called esculin– if it is converted to esculetin, it will react with iron in the media and turn completely black… bile acids in this media inhibit the growth of most gram positive organisms

Question 16

bile esculin (BE) slant negative result

Answer 16

tan

Question 17

bile esculin (BE) slant positive result

Answer 17

BLACK

Question 18

bile esculin (BE) slant positive result

Answer 18

BLACK

Question 19

DNase

Answer 19

breaks down DNA to nucleotides by adding HCl to the DNA plate after microbes have been cultured– the low pH causes DNA to precipitate within the media, turning the late cloudy. any areas where DNA has hydrolyzed will not precipitate, leaving clear areas around growth of positive cultures

Question 20

DNase (HCl) negative result

Answer 20

no clearing

Question 21

DNase (HCl) positive result

Answer 21

CLEARING

Question 22

sheep blood agar

Answer 22

some bacteria break down blood cells using toxins called hemolysins… resulting in three patterns of hemolysis clearings- alpha, beta, and gamma… additionally, bacitracin and optochin are antibiotics used to determine susceptibility

Question 23

alpha hemolysis

Answer 23

partial breakdown of red blood cells– resulting in smoky green color (no longer red but no clearing)

Question 24

beta hemolysis

Answer 24

complete breakdown of red blood cells, resulting in complete clearing– can read text through the plates

Question 25

gamma hemolysis

Answer 25

no clearing, the plates have growth on them but are just as red

Question 26

hemolysis results

Answer 26

alpha (A), beta (B), or gamma (G)

Question 27

bacitracin

Answer 27

an inhibitor of peptidoglycan biosynthesis that group A streptococci are particularly susceptible to

Question 28

bacitracin negative result

Answer 28

no zone (R)

Question 29

bacitracin positive result

Answer 29

ZONE (S)

Question 30

optochin

Answer 30

a copper containing compound that pneumococci are particularly susceptible to

Question 31

optochin negative result

Answer 31

no zone (R)

Question 32

optochin positive result

Answer 32

ZONE (S)

Question 33

competition

Answer 33

a contest between organisms for territory, a niche, or resources; neither organism fully thrives as both are somewhat harmed; example: soil bacteria for carbon sources

Question 34

cooperation

Answer 34

process of groups of microbes working or acting together for their common/mutual benefit; both organisms can benefit from this interaction; example: quorum sensing

Question 35

predation

Answer 35

interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked); predator benefits but the prey does not; example: Paramecium consuming bacteria

Question 36

mutualism

Answer 36

relationship between two organisms in which individual benefits from the activity of the other; example: lichen, ruminants, and alfalfa

Question 37

commensalism

Answer 37

class of relationships between two organisms where one organism benefits without affecting the other; example: many members of the human microbiota that benefit from humans but the humans do not benefit

Question 38

amensalism

Answer 38

an interaction where an organism inflicts harm to another organism without any costs or benefits received by the actor; example: antibiotic production by a fungus

Question 39

parasitism

Answer 39

interaction where one species (the parasite) benefits at the expense of the other (the host); example: bacteriophage T4 (and all viruses in general)

Question 40

three main functions of the wastewater plant

Answer 40

1. physical removal of large and undesirable objects -> 2. Biological and/or chemical removal of excess organic material -> 3. disinfection to reduce the number of potential pathogens

Question 41

head works

Answer 41

facilities where wastewater enters a wastewater treatment plant

Question 42

screw pumps

Answer 42

efficient means of lifting large quantities of water or wastewater at low heads

Question 43

grit and grease removal

Answer 43

Horizontal flow velocity is reduced to allow heavy particles to settle while grease and other floating substances are allowed to rise to the surface to be separated. An aeration system is utilized to keep the majority of organic materials in suspension during this process.

Question 44

aeration basins

Answer 44

Aerobic bacteria and protists consume organic material of wastewater

Question 45

equalization basin

Answer 45

maintain a constant volumetric flow of wastewater from pretreatment to other downstream operations

Question 46

FeCl3 addition

Answer 46

remove impurities in water and for wastewater treatment.

Question 47

clarifiers

Answer 47

Tanks that allow solids in the water to settle to the bottom

Question 48

UV irradiation

Answer 48

another disinfection method for destroying disease-causing organisms in wastewater effluent in onsite wastewater treatment systems; destroys the genetic material of microorganisms which prevents them from reproducing.

Question 49

sludge thickener

Answer 49

to concentrate the solids, thus reducing the volume of sludge.

Question 50

aerobic digesters

Answer 50

The activated sludge from the final clarifiers comes here and is reduced by cannibalism.

Question 51

sludge storage

Answer 51

any combination of drying beds, lagoons, separate tanks and pad areas to store liquid, dewatered or dried sludge