Microbiology Exam 4

All Parts

Exogenous electron acceptor (fermentation or respiration?)

Respiration

Pyruvate or derivative as electron acceptor (fermentation or respiration?)

Fermentation

Fermented foods

Chocolate, dairy products, meat products, vegetables and vegetable products, and yeast bread

Fermentation in food used for...

Food preservation

Fermentation in food may involve...

A succession of microbes

Fermentation in food is a \___ process

Self-limiting

Self-limiting process

Fermentation products inhibit fermenters

Fermentation in food changes \___ of the food

The flavor, odor, and texture

Dairy products are fermented using \___ bacteria

Lactic acid (LAB)

Characteristics of lactic acid bacteria

Acid-tolerant, aerotolerant, Gram-positive, non-spore forming, and strictly fermentative

Examples of lactic acid bacteria genus

Lactobacillus, lactococcus, leuconostoc, and streptococcus

Probiotics in yogurt are not necessarily...

The fermentative bacteria

Probiotics

Live microorganisms which, when administered in adequate amounts, confer a health benefit to the host

Sources of probiotics

Dietary supplements, fermented food, and non-oral supplements

Prebiotics

Substances (such as food) that promote the growth of probiotics

Probiotics must have \___ in order to survive inside one's body

Prebiotics

Can protect probiotics against stomach acid

Fat in yogurt

Pros of probiotics (5)

Considered safe for healthy individuals (nonpathogens), immunomodulation, improve general intestinal balance and health, improve oral health, and may lower blood pressure and serum cholesterol

How can probiotics improve general intestinal balance and health? (5)

Anticancer effects, colonization resistance, control of diarrhea, improve lactose intolerance, and treatment of enteric disease

Area of immunomodulation

Intestines

Cons of probiotics (3)

Difficult to accurately assess effectiveness, may cause mild side effects and systemic infection in severely immunocompromised individuals, and not regulated by FDA

Why is the effectiveness of probiotics difficult to accurately assess?

Each individual and each probiotic is different

How can the fact that probiotics are not regulated by the FDA be problematic?

Misleading advertising, most yogurts have relatively low CFU counts, and voluntary "Live Active Culture" seal

Voluntary "Live Active Culture" seal at time of...

Manufacture

Probiotics may becomes \___ in severely immunocompromised individuals

Opportunistic pathogens

Alcoholic beverages produced by...

Yeast from fermentation of sugar to CO2 and ethyl alcohol

Production of alcoholic beverages begins with...

Formation of liquid containing carbohydrates in readily fermentable form

Wine

Fermentation of grape juice

Beer

Fermentation of malted grain

Distilled beverages

Distillation of fermented solutions

Distilled beverages to make...

More concentrated alcohol

The science of wine production

Enology

Steps of wine production (4 - in order)

Must preparation, fermentation, aging, and racking

Steps of must preparation (2 - in order)

Grapes are crushed to yield must, must treated with sulfur dioxide fumigant, and Saccharomyces cerevisiae or S. elliposideus added

Types of wine fermentation

Primary and secondary

Primary wine fermentation

3-5 days at 20-28 degrees C

Secondary wine fermentation

1-3 weeks at ~20 degrees C

Secondary wine fermentation is also called...

Malolactic wine fermentation

Wine aging allows...

Bitter components to dissipate

Racking removes...

Sediment during fermentation

Alcohol content of wine

10-14%

How is sweet wine produced?

Fermentation is stopped before the fermentation of sugar can occur

How is sparkling wine produced?

CO2 byproduct is trapped

First two steps of ale and beer production (in order)

Mash and wort

Mashing

Process used to release fermentable sugars from grains

How to yield mash

Activation of enzymes and germination of grains to yield malt, and malt transferred to mash tun and mixed with water

Steps of wort production

Mash heated with hops in brew kettle and then hops are removed

Purpose of hops

Assist in clarification (i.e., serves as an antimicrobial) and provide flavor

Heating of mash to produce wort...

Inactivates hydrolytic enzymes

Wort

Clear liquid containing fermentable carbohydrates

Latter four steps of ale and beer production (in order)

Wort pitched, fermentation, storage, and bottling

Pitch

To inoculate wort with desired yeast

Types of yeasts used to pitch wort

Bottom yeast and top yeast

Bottom yeast

Sit on bottom and used in production of lager beers

Lagering

Storage (of ale and beer)

Top yeast

Float to top and used in production of ales

More CO2 (bottom yeast or top yeast?)

Top yeast

More foam (bottom yeast or top yeast?)

Top yeast

Higher pH (bottom yeast or top yeast?)

Bottom yeast

Fermentation of lager beer

7-12 days at 6-12 degrees C

Fermentation of ale

5-7 days at 14-23 degrees C

Usually added at bottling of ale and beer

CO2

How is CO2 added at bottling of ale and beer?

Using sugar

At bottling, beer can be...

Pasteurized or sterilized by filtration

Alcohol content of ale and beer

2-25%

Not supposed to be aged

Ale

Supposed to be consumed warm

Ale

Scotch

Whiskey made in Scotland

Bourbon

Whiskey made in Kentucky that is 25-50% corn

Extension of beer-making process

Whiskey

Distilled spirits

Liquor

Whiskey and bourbon begin with...

Sour mash

Sour mash (of whiskey and bourbon) is inoculated with...

Homolactic bacteria

Following fermentation, sour mash (of whiskey and bourbon) is...

Distilled to concentrate alcohol

Color of fresh distillate

Colorless

Color development of distillate occurs during...

Aging

Virus

Genetic elements that replicate independently of a cell's chromosome but require a living host in order to reproduce

Viruses are \___ parasites

Obligate intracellular

Viruses infect \___ cell types

All

Viruses are \___ infectious agents

Acellular

Viruses contain...

DNA or RNA

DNA or RNA segments in viruses

Circular, double or single stranded, linear, or segmented

Extracellular form of a virus

Virion

Virion

The complete virus particle

Virion composed of...

Nucleic acid surrounded by a protein coat and possibly external layers

Virion size range

10-2300 nm in diameter

Virion contains...

Nucleocapsid

Nucleocapsid

Nucleic acid (DNA or RNA) + protein coat (capsid) (some have additional components)

Types of virus symmetry

Complex, helical, and icosahedral

Purpose of nucleocapsid

Protect the nucleic acid

Capsomeres

Protein subunits that make up capsid

Helical symmetry

Virus RNA coiled and surrounded with capsomeres

Icosahedral symmetry

Geometric shape

Types of complex symmetry

Binal and vaccinia

Example of binal symmetry

T4 bacteriophage

Why is binal symmetry called binal symmetry?

Has both helical and icosahedral symmetry

Even though viruses are not living, they are still classified using...

Genus and species

Capsid \= \___ symmetry

Helical

Types of ssRNA viruses

Negative sense and positive sense

Positive sense viruses

Genome and mRNA are the same, plus strand, and positive