Exam 2 Prep Flashcards

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0
Q

Define log or exponential growth phase

A

Cultures are accustomed to environmental conditions
Rapid growth/shortest generation time
Cells tend to be their largest.
Drugs are most effective.

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1
Q

Define lag phase of bacterial growth curve.

A

Little to no growth
cells need time to detect environment
turn on/off genes necessary to use nutrients available in the environment
Length of legacies waries depending on differences between old and new environments

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2
Q

Define stationary phase

A

Growth rate equals death rate as nutrients decrease and waste products accumulate.
Approximately 1 billion cells per milliliter.
Sporulation phase begins.

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3
Q

Define death/decline phase

A

Without nutrients, all cells begin to die. Death rate is exponential.

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4
Q

What is the apparatus called in which a continuous culture is produced?

A

Chemostat, uniform growth.

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5
Q

Viral one step growth curve cell life cycle basics

A

Attachment, penetration, synthesis(transcription/translation), release of virus, building of the virus if it is enveloped

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6
Q

Steps of the viral one step growth curve

A

Decline phase-virus attaches and penetrates the cell
Eclipse phase-synthesis
Rise phase-being released from cell and are budding
Burst size=final-initial

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7
Q

Serial dilutions are used for ________ samples; filtration will be used on __________ samples.

A

Concentrated,dilute

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8
Q

Define CFU

A

Colony forming unit

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9
Q

Bacterial pop equation

A

Number of colonies / dilution

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10
Q

Standard plate count for viruses is called a….

A

Plaque assay

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11
Q

Plaque assays-area of dead cells that appears as a ________ _______ on the petridish

A

Clear spot

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12
Q

Plaque assay tells us about _____ _____ and measures ______ ______.

A

Live bacteria, viable bacteria

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13
Q

Direct microscopic count of bacteria or viruses requires…..

A

Electron microscope

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14
Q

All microbes have _______ _______ conditions, by altering those conditions one can control the ________.

A

Growth conditions, growth

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15
Q

Psychro- prefix means

A

Cool or cold

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16
Q

Name the four subdivisions of microbial growth as far as temperature is concerned.

A
Cold to hot
Psychrophiles
Mesophiles
Thermophiles
Hyperthermophiles
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17
Q

Microbes that make human sick generally are…

A

Mesophiles

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18
Q

________ (deli meat) causes diarrhea or miscarriage of a child for a woman.

A

Listeria

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19
Q

Hyperthermophiles are typically ________ and live in volcanic vents at the bottom of the ocean.

A

Archea bacteria

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20
Q

________ have less saturated fatty acids ________ have more saturated fatty acids.

A

Psychrophiles, hyperthermophiles

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21
Q

What type of ocean food is bacterial overloaded

A

Shelfish or filter feaders

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22
Q

Fibrogenious are….

A

Organisms bacteria that infects shellfish

23
Q

Pasteurization gets rid of what type of bacteria

A

Mesophiles, Bacteria that gets humans sick

24
Q

Disinfection versus sterilization depends on…

A

How hot it gets

25
Q

Define autoclave

A

Sterilization using steam under pressure

Similar to pressure cooker

26
Q

Define incineration.

A

Depends on temperature, thousands of degrees burn to ash

Disinfection is heating not quite to ash

27
Q

Define pasteurization

A

LTLT/HTST Low temperature low time 65 C, high-temperature short time 75 C

Sanitation

28
Q

Defined refrigeration

A

Preservation that prevents growth

29
Q

Define freezing

A

Preservation or disinfection which prevents growth

-80°C

30
Q

40-140 rule

A

Food should be kept below 40°F or above 140°F

31
Q

Bacteria do not need ________ to grow.

A

O2

32
Q

True aerobes need _______ to grow

A

Oxygen

33
Q

Microaerophiles grow at….

A

Reduced oxygen concentrations

34
Q

Facultative anaerobes grow in the _______ or ________ of oxygen.

A

Presences, absence

35
Q

Define anaerobes

A

Obligate anaerobes cannot tolerate any oxygen

Aerotolerant anaerobes can tolerate oxygen but will not grow in its presence

36
Q

Metabolism creates ________ ________.

A

Oxygen radicals

37
Q

Superoxide dismutase, peroxidase, and catalase help….

A

Remove oxygen radicals to prevent cell damage

38
Q

Effects of pH on microbial growth

A

Acidophiles 8

39
Q

In acid cells can prevent influx of hydrogen by exchanging ____ for intracellular H. In acid cells can use Na+/H+ transporters to exchange internal ____ for H+.

A

K+, Na+

40
Q

Things cannot live very well when this percentage goes down.

A

Water

41
Q

Define Osmotolerant bacteria

A

Bacteria that can survive higher elevations of salt in environment

42
Q

Define halophilic bacteria

A

Salt loving bacteria

43
Q

Define osmophilic/xerophilic molds

A

Molds that love Osmonic pressure from anything like salts, spices or sugars

44
Q

Aw

A

Water activity, refers to the availability of water

45
Q

These channel proteins move water in and out rapidly

A

Aquaporins

46
Q

UV radiation between _____-_____ nanometers damages DNA through the formation of thymine fibers.

A

260-280

Low penetration levels makes it good for surfaces and thin layers

47
Q

Define dimerize

A

Kink in DNA caused by uv radiation

48
Q

UV radiation ultimately creates ________ in mRNA and DNA

A

Mutations

49
Q

UV light can only disinfect about the top ______ of water

A

Inch

50
Q

Ionizing radiation is known as….

A

Cold sterilization

51
Q

… Shatters DNA completely

A

Gamma rays or x-rays

52
Q

Bacteria have a good repair mechanisms that can fix…

A

Thymine dimers

53
Q

Bacteria have ____ chromosome.

A

One

54
Q

Td=In2/mu

A

Doubling time=natural log2/growth rate