POST LAB 2

Question 1

List some beneficial and harmful qualities of yeast and molds

Answer 1

✅Fermented food and beverages production
❌Opportunistic pathogens
✅Antibiotics and vitamin production
❌ Spoilage of food
✅Biodegradation and Bioremediation
❌ Mycotoxins

Question 2

In the Riddell slide culture method, to increase relative humidity inside the plate

Answer 2

Moistened Filter Paper

Question 3

In the Riddell slide culture method, prevents the contact with the moist paper which could disturb the growth of the mold

Answer 3

U-shaped rod

Question 4

Advantage of Riddell slide culture over LPCB

Answer 4

✅Observe live mold cultures ✅cost-effective and rapid ✅Morphology observation has less interference

Question 5

Plates are not inverted during incubation of fungi culture because…

Answer 5

Aerial hyphae and spores might fall on the lid and spread in the plate causing secondary growths

Question 6

Advantages of observing molds in agar surface.

Answer 6

✅Individual colonies can be observed without interference.
✅Obverse and reverse sides can be observed.
✅Different morphological characteristics can be distinguished (size, texture, presence of aerial hyphae etc.)

Question 7

How do we account for for mold preferring to grown in vitro rather than in vivo?

Answer 7

in vitro conditions (e.g. nutrient rich agar, controlled temperature) are conducive for the growth of filamentous mold. Moreover, in in vivo there exists competition between different microorganisms

Question 8

True hyphae; typically reproduce by spores or mitosis; mostly appear filamentous in in vitro culture; multicellular

Answer 8

Molds

Question 9

No hyphae or has pseudohyphae; typically reproduce by budding and cannot produce spores; mostly appear smooth in in vitro culture; unicellular

Answer 9

Yeast

Question 10

asexual spores produce from budding in yeasts such as Candida

Answer 10

blastospores

Question 11

asexual non-motile spores exogenously produced by mitotic division at the tip of conidiophores. These are found in ascomycetes, basidiomycetes and deuteromycetes

Answer 11

✅conidia

Question 12

specialized hyphal branch where conidia are produced and where they mature and break-off

Answer 12

✅conidiophore

Question 13

sac-like structures where sporangiospores are produced through cleavage

Answer 13

✅sporangium

Question 14

non-motile asexual spores produced in the sporangium. These are produced by zygomycetes.

Answer 14

✅sporangiospores

Question 15

a primitive form of asexual spores formed by the fragmentation of a hyphae. Typically produced by yeast-like fungi, dermatophytes and basidiomycetes

Answer 15

✅arthrospores

Question 16

thick-walled resting asexual spores whose function is for survival (perennation) found in various species such as Candida albicans, Panus and Motierellales

Answer 16

✅chlamydospores

Question 17

Fungal spores vs. Bacterial Endospores

1 cell:many spores, for reproduction, less resistant, asexual/sexual

Answer 17

Fungal spores

Question 18

Fungal spores vs. Bacterial Endospores

1 cell:1 endospore, for survival, very resistant

Answer 18

Bacterial endospores

Question 19

S. aureus with

Sulfamethoxazole
Imipenem
Trimethoprim
Ciprofloxacin

Answer 19

Sensitive
Resistant
Resistant
Sensitive

Question 20

E. coli with

Sulfamethoxazole
Imipenem
Trimethoprim
Ciprofloxacin

Answer 20

Sensitive
Intermediate
Intermediate
Intermediate

Question 21

P. aeruginosa with

Sulfamethoxazole
Imipenem
Trimethoprim
Ciprofloxacin

Answer 21

Resistant
Resistant
Resistant
Resistant

Question 22

MIC in broth vs MBC in agar

Answer 22

MIC - The absence of turbidity (growth) in broth when doing AST can either be a result of the inhibition or absence of viable cells.

MBC - After re-introduction in agar, The absence of colonies (growth) can be solely attributed to the absence of viable cells.

Question 23

Mode of actions of the antibiotics used

inhibits folic acid synthesis, inhibits purine synthesis

Answer 23

Sulfamethoxazole

Question 24

Mode of actions of the antibiotics used

inhibits cell wall synthesis

Answer 24

Imipenem

Question 25

Mode of actions of the antibiotics used

inhibits DNA gyrase

Answer 25

Ciprofloxacin

Question 26

Mode of actions of the antibiotics used

inhibits folic acid synthesis, inhibits purine synthesis

Answer 26

Trimethoprim

Question 27

Mueller Hinton Agar for AST?

Answer 27

MHA is nutrient rich medium devoid of inhibitors that affects the performance of antibiotics, ensuring that the results of AST is more accurate

Question 28

energy transfer/energy exchange through electrons transfers. These transfers have corresponding energy currencies which could dictate how a reaction is favored or if it is energy-generating, -neutral or -intensive.

Answer 28

Redox reaction

Question 29

Why is glucose not broken down in one step?

Answer 29

✅Energy intensive
✅Cells doesn’t need to produce energy all the time
✅Metabolic “checkpoints” are necessary in order to not produce too much product
✅Thus, some enzymes act as regulatory checkpoints through feedback inhibition.

Question 30

Cell respiration vs. fermentation

Answer 30

✅Glycolysis + Krebs Cycle + ETS = Respiration
Products: Higher no. of ATP, CO2, H2O

✅Glycolysis only = Fermentation
Products: Lower no. ATP, CO2, acids, ethanol

Question 31

What pathway is common among cellular respiration, ethanol fermentation, and lactic acid
fermentation? Explain this pathway briefly.

Answer 31

✅Glycolysis is common among the three pathways. It is the catabolism of glucose to produce pyruvate, 2 ATP and 2 NADH.

Question 32

Products of Ethanolic Fermentation

Answer 32

Ethanol and Carbon Dioxide

Question 33

Effect of the fruit in wine making

Answer 33

✅The type of fruit affects the wine product, ideally fruits with high sugar content and low pH are
preferred. The differences in sugar content and pH, presence of other phytochemicals can affect the
organoleptic properties of wines.

Question 34

study of wine-making, employing techniques in microbiology, horticulture, plant physiology and engineering which suggests that it can be an exact science.

Answer 34

Oenology

Question 35

Purpose of lime water trap

Answer 35

✅lime or Ca(OH)2 reacts with the CO2 (becomes CO3 2- when dissolved) to produce a milky white precipitate CaCO3 to indicate that fermentation is occuring.

Question 36

is a gram-positive, homofermentative rod-shaped bacteria capable of producing lactic acid using hexose sugars, which is why it used in fermenting yogurt to milk.

Answer 36

Lactobacillus delbrueckii subsp. bulgaricus

Question 37

Lactic acid fermentation products

Answer 37

2 lactic acid and 2 net ATP

Question 38

Will the type of milk affect the yogurt?

Answer 38

The thickness of the yogurt results from the coagulated proteins determined by the fat content of the milk, the yogurt starter, and amount of milk solids (protein). Adding nonfat milk powder (milk solids) to cold milk before heating will result in a firmer yogurt. However, adding nonfat milk powder to heated milk will cause some proteins to coagulate and form strings

Question 39

What is the purpose of adding powdered milk?

Answer 39

Powdered milk is a source of milk solids which contributes to the firmier or creamier texture of the yogurt.

Question 40

Why is it necessary to re-sterilize/reheat the milk-sugar-LAB culture mixture?

Answer 40

✅Kills competing bacteria
✅It denatures and coagulates whey protein increasing viscosity

Question 41

Why do we use indicator microorganisms instead of directly detecting pathogens?

Answer 41

✅Number of pathogens is at an undetectable level (low count).
✅Pathogens are unculturable in laboratory settings.
✅Other microorganisms may outcompete the pathogen when cultured.

Question 42

Characteristics of a good indicator microorganism?

Answer 42

✅Longer survival period and high survival rate
✅Easily detectable and culturable
✅Commensals that inhabit the mammalian gut w/c indicates fecal contamination

Question 43

A medium used for confirmatory testing in MTFT.

Contains lactose, lactose fermenting coliforms will produce gas.

Answer 43

BGLBB

Question 44

contains ox bile and brilliant green dye which inhibits gram positive bacteria and other
non-coliform gram negative

Answer 44

BGLBB