Microbiology Final Part 3

Question 1

Basidiomycota

Answer 1

-Filamentous or yeasts
-Production of basidiospores on basidium
Production of complex fruiting bodies

Question 2

Ectomycorrhizae

Answer 2

-“Outside fungus root”
-Specific mycorrhizae that grown on actively growing fine roots
-Dominate in temperate forests

Question 3

In what population is mushroom poisoning most common?

Answer 3

Incidents of mushroom poisoning have benn notable in people who are newly arrived in North America

Question 4

What is responsible for most mushroom-related deaths? What are they?

Answer 4

-Amanitins
-Cyclic peptides which are hepatotoxins, nephrotoxic, etc
-Leads to death

Question 5

What do amanitins do in the body?

Answer 5

-Potent inhibitors of RNA Polymerase II
-No true antidote. Best option is fluids and liver transplant
-Several genera produce amatoxins, most common in Amanita species

Question 6

What is the potential antidote for amanitins ?

Answer 6

-Milk thistle could help
-Silibinin may prevent uptake of amanitins (and other drugs) into cells

Question 7

Respiration

Answer 7

Externally-driven electron acceptor, either O2 or some other oxidant

Question 8

Fermentation

Answer 8

Redox reactions in the absence of an added electron acceptor

Question 9

What is the pathway for fermentation?

Answer 9

Glycolysis
Glucose → pyruvate→ lactic acid, ethanol, CO2, or ethanol + CO2

Question 10

Why are fermented foods so common?

Answer 10

-Preservation of food
-Improved digestibility
-Addition of nutrients and flavors

Question 11

How is chocolate produced?

Answer 11

-Complex fermentation process
-Cacao seeds are fermented by 1) yeasts, 2) lactic acid bacteria, and 3) acetic acid bacteria
-Essentially has the process of microbial succession, and the process depends entirely on indigenous microbial fermentation

Question 12

What is used to produce soy products?

Answer 12

Aspergillus oryzae

Question 13

Saccharomyces cerevisiae

Answer 13

-Baker’s yeast
-Brewer’s yeast
-Model organism for eukaryotic cellular biology

Question 14

What is the energy metabolism in S. cerevisiae?

Answer 14

sugar + O2 → CO2 + H2O + High energy
See flashcard for more metabolism

Question 15

How is bread made?

Answer 15

-Ethanol fermentation by Saccharomyces
-Alcohol is boiled off

Question 16

When was wine first made and why was it so popular?

Answer 16

-Evidence for wine making dates to ~6000 BC
-Safer to drink than water before filtration, refrigeration

Question 17

Primary Fermentation of Wine via Saccharomyces

Answer 17

-Sugar → Ethanol + CO2
-Fermentation is inhibited when ethanol reaches about 15%
-Amount of starting sugar determines sweetness of wine

Question 18

Secondary Fermentation of Wine

Answer 18

-Malolactic fermentation (2^0 fermentation)
-Malic acid → lactic acid + CO2
-Buttery mouthfeel
-Oenococcus oeni

Question 19

When was beer discovered?

Answer 19

-Mesopotamian pictogram, 4000 BC
-Beer was not invented, it was discovered

Question 20

What microbes are used to make sour beers?

Answer 20

-3 special microbes are used to make sour beer
-Brettanomyces (instead of Sacc.)
-Lactobacillus
-Pediococcus
-Acetic acid and lactic acid fermentation in addition to alcoholic fermentation

Question 21

How is cheese fermented?

Answer 21

1° fermentation:
-lactic acid bacteria
-Casein insoluble in acidic environment, results in curds and whey
-Rennet: proteolytic enzymes from 4th stomach of a calf
2° fermentation:
-Requires microbes such as bacteria and fungi
Ex:
-Propionbacter shermanii
-Penicillium camemberti
-Penicillium roqueforti

Question 22

Microbial communities of cheese

Answer 22

-Complex microbial communities
-The top layer of many chesses is considered a bofilm
-Microbial succession is also important in cheese, meaning that one microbe will take over after another

Question 23

How are pickled foods made?

Answer 23

Using acetic acid and lactic acid producing bacteria, which grow in a salty brine

Question 24

Spirulina

Answer 24

-Cyanobacterium
-Some consider it a “super food”
-Also fish food

Question 25

Fusarium venenatum

Answer 25

-Ascomycota fungus
-Mold
-Meat substitute

Question 26

Agaricus bisporus

Answer 26

-Cremini, portobello, baby bella, button mushroom, champignon mushroom
-Basidiomycota fungus
-More than $800 million produced per year