Exam 2 Prep

Question 0

Define log or exponential growth phase

Answer 0

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

Question 1

Define lag phase of bacterial growth curve.

Answer 1

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

Question 2

Define stationary phase

Answer 2

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

Question 3

Define death/decline phase

Answer 3

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

Question 4

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

Answer 4

Chemostat, uniform growth.

Question 5

Viral one step growth curve cell life cycle basics

Answer 5

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

Question 6

Steps of the viral one step growth curve

Answer 6

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

Question 7

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

Answer 7

Concentrated,dilute

Question 8

Define CFU

Answer 8

Colony forming unit

Question 9

Bacterial pop equation

Answer 9

Number of colonies / dilution

Question 10

Standard plate count for viruses is called a….

Answer 10

Plaque assay

Question 11

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

Answer 11

Clear spot

Question 12

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

Answer 12

Live bacteria, viable bacteria

Question 13

Direct microscopic count of bacteria or viruses requires…..

Answer 13

Electron microscope

Question 14

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

Answer 14

Growth conditions, growth

Question 15

Psychro- prefix means

Answer 15

Cool or cold

Question 16

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

Answer 16

Cold to hot
Psychrophiles
Mesophiles
Thermophiles
Hyperthermophiles

Question 17

Microbes that make human sick generally are…

Answer 17

Mesophiles

Question 18

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

Answer 18

Listeria

Question 19

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

Answer 19

Archea bacteria

Question 20

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

Answer 20

Psychrophiles, hyperthermophiles

Question 21

What type of ocean food is bacterial overloaded

Answer 21

Shelfish or filter feaders

Question 22

Fibrogenious are….

Answer 22

Organisms bacteria that infects shellfish

Question 23

Pasteurization gets rid of what type of bacteria

Answer 23

Mesophiles, Bacteria that gets humans sick

Question 24

Disinfection versus sterilization depends on...

Answer 24

How hot it gets

Question 25

Define autoclave

Answer 25

Sterilization using steam under pressure | Similar to pressure cooker

Question 26

Define incineration.

Answer 26

Depends on temperature, thousands of degrees burn to ash Disinfection is heating not quite to ash

Question 27

Define pasteurization

Answer 27

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

Question 28

Defined refrigeration

Answer 28

Preservation that prevents growth

Question 29

Define freezing

Answer 29

Preservation or disinfection which prevents growth | -80°C

Question 30

40-140 rule

Answer 30

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

Question 31

Bacteria do not need ________ to grow.

Answer 31

O2

Question 32

True aerobes need _______ to grow

Answer 32

Oxygen

Question 33

Microaerophiles grow at....

Answer 33

Reduced oxygen concentrations

Question 34

Facultative anaerobes grow in the _______ or ________ of oxygen.

Answer 34

Presences, absence

Question 35

Define anaerobes

Answer 35

Obligate anaerobes cannot tolerate any oxygen | Aerotolerant anaerobes can tolerate oxygen but will not grow in its presence

Question 36

Metabolism creates ________ ________.

Answer 36

Oxygen radicals

Question 37

Superoxide dismutase, peroxidase, and catalase help....

Answer 37

Remove oxygen radicals to prevent cell damage

Question 38

Effects of pH on microbial growth

Answer 38

Acidophiles 8

Question 39

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+.

Answer 39

K+, Na+

Question 40

Things cannot live very well when this percentage goes down.

Answer 40

Water

Question 41

Define Osmotolerant bacteria

Answer 41

Bacteria that can survive higher elevations of salt in environment

Question 42

Define halophilic bacteria

Answer 42

Salt loving bacteria

Question 43

Define osmophilic/xerophilic molds

Answer 43

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

Question 44

Aw

Answer 44

Water activity, refers to the availability of water

Question 45

These channel proteins move water in and out rapidly

Answer 45

Aquaporins

Question 46

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

Answer 46

260-280 Low penetration levels makes it good for surfaces and thin layers

Question 47

Define dimerize

Answer 47

Kink in DNA caused by uv radiation

Question 48

UV radiation ultimately creates ________ in mRNA and DNA

Answer 48

Mutations

Question 49

UV light can only disinfect about the top ______ of water

Answer 49

Inch

Question 50

Ionizing radiation is known as....

Answer 50

Cold sterilization

Question 51

... Shatters DNA completely

Answer 51

Gamma rays or x-rays

Question 52

Bacteria have a good repair mechanisms that can fix...

Answer 52

Thymine dimers

Question 53

Bacteria have ____ chromosome.

Answer 53

One

Question 54

Td=In2/mu

Answer 54

Doubling time=natural log2/growth rate