Lecture 2

Question 1

Bacterial communities that secrete polysaccharides and other hydrophilic polymers. The mesh-like accumulation helps protect the bacteria from antibiotics and disinfectants. This slippery, grimy surface is called?

Answer 1

Bioflim

Question 2

A population descended from a single cell and therefore contains only one species

Answer 2

A Pure Culture

Question 3

A polysaccharide extracted from seaweed used to solidify culture media

Answer 3

Agar

Question 4

Qualities of a petri dish

Answer 4

It excludes airborne contaminants but is not airtight
two-part covered container made of plastic or glass
Culture medium in Petri dish is referred to as a plate of that medium

Question 5

The method of using a sterile loop to spread a small culture sample over a medium in a pattern that gradually thins out the sample, resulting in isolated colonies

Answer 5

Streak plate method

Question 6

Qualities of Batch culture

Answer 6

1. Nutrients are not renewed
2. Wasters are not removed
3. Typically involves growth of bacteria or Archean either on agar plates or in tubes of broth
4. It is a closed system

Question 7

A distinct mass of microorganisms which develop from a single cell growing on a solid medium

Answer 7

Colony

Question 8

Order of normal bacterial growth curve

Answer 8

1. Lag phase
2. Exponential or log phase
3. Stationary phase
4. Death phase
5. Prolonged decline phase

Question 9

the initial phase after bacterial cells are placed into a new environment and are gearing up for cell division, but their numbers have not yet increased

Answer 9

Lag Phase

Question 10

During what phase of the growth curve is generation time measured?

Answer 10

Log/exponential phase

Question 11

Phase of growth in which the number of new cells balance the number of declining cells

Answer 11

Stationary phase

Question 12

Phase in which the number of viable cells is decreasing

Answer 12

Death phase

Question 13

In what ways is microbial growth in a colony the same as growth in a liquid?

Answer 13

Both involve a lag phase followed by exponential growth
In both cases, cells compete with one another for available nutrients

Question 14

Device used to keep cells in a state of constant growth

Answer 14

Chemostat

Question 15

Term used to describe microorganisms that live in harsh environments that kill most other organisms

Answer 15

Extremophiles

Question 16

Environmental factors that have the most impact on microbial growth

Answer 16

Atmosphere, pH, water availability, and temperature

Question 17

Term for a microorganism that has an optimum temperature between -5 C and 15 C

Answer 17

Psychrophile

Question 18

Term for a microorganism that has an optimal temp between 15 C and 30 C but grows best on refrigerated foods

Answer 18

Psychrotroph

Question 19

E. coli and most other common bacteria are in what optimal temperature group?

Answer 19

Mesophiles

Question 20

Thermophiles would most likely be found where?

Answer 20

Hot springs and compost heaps

Question 21

Strictly aerobic organism, requires O2 for survival

Answer 21

Obligate aerobe

Question 22

Human pathogens, adapted to growth in the body belong to which temperature group?

Answer 22

Mesophiles

Question 23

Microorganisms that can grow without O2 but grow faster in the presence of O2

Answer 23

Facultative anaerobes

Question 24

Microorganisms that cannot multiply if O2 is present, often killed by brief exposure to air

Answer 24

Obligate anaerobes (anaerobes)

Question 25

Microorganisms that require small amounts of O2 for aerobic respiration. Large quantities of O2 inhibit their growth

Answer 25

Microaerophiles

Question 26

Microorganisms that are indifferent to O2, can grow in its presence but do not use O2 to harvest energy

Answer 26

Aerotolerant Anaerobes (aka obligate fermenters cus fermentation is their only metabolic option)

Question 27

Microorganisms that are indifferent to O2, can grow in its presence but do not use O2 to harvest energy

Answer 27

Aerotolerant Anaerobes (aka obligate fermenters cus fermentation is their only metabolic option)

Question 28

An aerobe that could be found on the surface of the skin, in the large intestine, or a deep wound

Answer 28

Facultative anaerobe

Question 29

Water diffuses out of a cell due to osmosis. This results in what?

Answer 29

Plasmolysis

Question 30

organism that requires organic compounds for its carbon and energy needs

Answer 30

Heterotroph

Question 31

Prokaryotes that grow in alkaline conditions bring what into the cell?

Answer 31

Protons to neutralize internal pH

Question 32

Organisms that use CO2 as a carbon source

Answer 32

Autotrophs

Question 33

Animals could not survive without autotrophs because without them the world would run out of ?

Answer 33

Organic carbon

Question 34

An organism that must consume organic matter is called a?

Answer 34

Heterotroph

Question 35

Some microorganisms convert nitrogen gas (N2) to ammonia in a process called?

Answer 35

Nitrogen fixation

Question 36

If an oil spill occurred in the ocean, what might we add to speed up the rate of microbial growth?

Answer 36

Nitrogen and phosphorus because they are often limiting nutrients in the ocean

Question 37

An organic compound that a microorganism cannot synthesize and therefore must be provided in the growth medium

Answer 37

A Growth Factor

Question 38

Process of autotrophs converting inorganic carbon to organic carbon

Answer 38

Carbon fixation

Question 39

An organism that gets its energy directly from sunlight

Answer 39

Phototroph

Question 40

A media containing ingredients like extracts of animals, plants, or yeasts, meat extracts, and blood and serum

Answer 40

Complex media

Question 41

A medium that contains an ingredient that inhibit is the growth of some bacteria while allowing others to grow

Answer 41

Selective medium

Question 42

Organism that uses light for energy and carbon dioxide as a carbon source

Answer 42

Photoautotroph

Question 43

Media that supports the growth of many microbes but contains substances that certain microbes change in recognizable way

Answer 43

Differential media

Question 44

How are liquid batch cultures most often aerated to support the growth of aerobic microbes?

Answer 44

They are grown in tubes or flasks that are continuously shaken

Question 45

Thayer-Martin agar is chocolate agar to which 3 or more antimicrobial drugs have been added. What type of medium is this?

Answer 45

Complex and selective

Question 46

Determines the number of total cells in a sample

Answer 46

Direct cell count

Question 47

Viable cell counts determine the number of?

Answer 47

Cells capable of multiplying

Question 48

A sample reduced in concentration through successive resuspension in the same volumes of diluent

Answer 48

Serial dilution

Question 49

Technique that uses a sterile tool, such as an L-shaped glass rod, to distribute a diluted sample evenly around the surface of a solid agar plate

Answer 49

The spread-plate technique

Question 50

Term that describes the appearance of a cloudy broth culture

Answer 50

Turbidity

Question 51

How many colony-forming units (CFUs) are presumed to result in a single colony using the viable plate method?

Answer 51

1

Question 52

A sterile object is free of?

Answer 52

All viable microorganisms and viruses

Question 53

The process of destroying or removing all microbes through physical or chemical processes is?

Answer 53

Sterilization

Question 54

Elimination of most or all pathogens on or in a material

Answer 54

Disinfection

Question 55

Antimicrobial chemical that is non-toxic enough to be used on skin

Answer 55

Antiseptic

Question 56

Chemical that kills harmful microbes

Answer 56

Germicide

Question 57

Chemical that kills bacteria

Answer 57

Bactericide

Question 58

Chemical that kills fungi

Answer 58

Fungicide

Question 59

Chemical that inactivates viruses

Answer 59

Virucide (notice “inactivate” because viruses are not living)

Question 60

The use of specific methods to prevent microbes from contaminating an environment is termed?

Answer 60

Aseptic technique

Question 61

Potentially harmful chemicals that form when chlorine and similar substances react with chemicals in the water

Answer 61

Disinfection by-products (DBPs)

Question 62

what 4 Microbial groups are the most resistant to Chemical control methods?

Answer 62

Protozoan cysts and oocysts, non-enveloped viruses, bacterial endospores, Mycobacterium species

Question 63

When selecting an appropriate chemical disinfectant, it is important to realize that the death rate is significantly influenced by _____ and _____

Answer 63

pH and temperature

Question 64

Prior to being used to grow cultures, media is ____ to ensure that the cultures remain pure

Answer 64

Sterilized

Question 65

What is the most highly resistant microbial structure?

Answer 65

Endospore

Question 66

3 categories of medical instruments according to their risk for transmitting disease

Answer 66

Critical, semi-critical, and non critical instruments

Question 67

Process that is an alternative to heat for sterilization and disinfection, but the process damages some types of plastics

Answer 67

Irradiation

Question 68

4 Physical ways to remove or destroy microbes

Answer 68

1. Filtration 2. Autoclaving 3. Incineration 4. Ultraviolet radiation

Question 69

A surgical scalpel is rated as a ____ instrument because it penetrates skin and mucous membranes and therefore must be sterile

Answer 69

Critical

Question 70

What methods of microbial control use moist heat to destroy microbes?

Answer 70

Pressurized steam (autoclave), boiling, and pasteurization

Question 71

Boiling water for at least ____ mins can be an effective means of killing vegetative cells and viruses

Answer 71

5 minutes

Question 72

The most highly resistant microbial structure is the bacterial _____

Answer 72

Endospore

Question 73

Goals of pasteurization

Answer 73

Destroy pathogens and reduce the number of microbes

Question 74

When boiling or pasteurizing a sample, microorganisms are destroyed because?

Answer 74

their proteins are irreversibly denatured

Question 75

Pasteurization protects against what pathogens in milks and juices?

Answer 75

Brucellosis, typhoid fever, and salmonellosis

Question 76

An instrument used to carry out sterilization at high temperature and pressure

Answer 76

Autoclave

Question 77

The destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes

Answer 77

Incineration

Question 78

Common parameters (settings) for an Autoclave

Answer 78

121C at 15psi for 15mins

Question 79

A retort is an industrial sized autoclave that ensure that ____ are destroyed

Answer 79

Endospores of Clostridium Botulinum

Question 80

Common dry heat sterilization method used in the microbiology laboratory

Answer 80

Flaming the inoculating loop

Question 81

Ionizing radiation causes indirect tissue damage by reacting with O2 to produce?

Answer 81

Reactive Oxygen Species (ROS)

Question 82

A form of electromagnetic radiation in wavelengths from 220-300nm that kills microbes via DNA damage

Answer 82

Ultraviolet light

Question 83

High pressure is thought to kill microbes by altering their?

Answer 83

Proteins and cell membranes

Question 84

What type of radiation has enough energy to remove electrons from atoms, thereby destroying DNA and damaging cytoplasmic membranes?

Question 85

What type of radiation has enough energy to remove electrons from atoms, thereby destroying DNA and damaging cytoplasmic membranes?

Question 86

What type of radiation has enough energy to remove electrons from atoms, thereby destroying DNA and damaging cytoplasmic membranes?

Question 87

What type of radiation has enough energy to remove electrons from atoms, thereby destroying DNA and damaging cytoplasmic membranes?

Answer 87

Ionizing

Question 88

What type of radiation has enough energy to remove electrons from atoms, thereby destroying DNA and damaging cytoplasmic membranes?

Answer 88

Ionizing

Question 89

_____ destroy all microbes including viruses and endospores

Answer 89

Sterilants

Question 90

Aqueous solutions of alcohol at a concentration of ____ are more effective than 100% alcohol

Answer 90

60-80%

Question 91

______ (HPP) is used to decrease the number of microbes in food while maintaining the color and flavor

Answer 91

High Pressure Processing

Question 92

______ (HPP) is used to decrease the number of microbes in food while maintaining the color and flavor

Answer 92

High Pressure Processing

Question 93

Alcohol-based solutions of certain antimicrobial chemicals like iodine are called?

Answer 93

Tinctures

Question 94

Chemical class that destroy microorganisms by forming chemical bonds that cross-link and inactivate proteins and nucleic acids?

Answer 94

Aldehydes

Question 95

Disinfectants that destroy all viruses and vegetative organisms but not endospores are referred to as ?

Answer 95

High-level disinfectants

Question 96

How do aqueous solutions of alcohol affect microbes?

Answer 96

By damaging lipid membranes and by denaturing proteins

Question 97

Formalin is 37% aqueous solution of _____ that is used as a potent chemical fixative and microbicide

Answer 97

Formaldehyde

Question 98

Chlorhexidine solutions are commonly used for?

Answer 98

Antisepsis of skin and skin wound care and mouthwashes

Question 99

Ethylene oxide is a gaseous agent used for?

Answer 99

Sterilizing heat or moisture-sensitive items

Question 100

Halogens are highly reactive ____ agents that _____

Answer 100

Oxidizing, cause damage to proteins

Question 101

Used to kill bacteria and inactive viruses in vaccines. It can also preserve biological specimens

Answer 101

Formaldehyde

Question 102

3 disadvantages of using chlorine to disinfect drinking water

Answer 102

At levels used, it does not kill cryptosporidium parvum oocysts and Giardia lamblia cysts , organic material disrupts its germicidal activity, It reacts with some organic compounds to form potential carcinogens

Question 103

Extremely useful gaseous sterilizing agent that destroys all microbes and is often used to sterilize fabric, equipment, and implantable devices

Answer 103

Ethylene oxide

Question 104

Chlorine and Iodine are common disinfectants that belong to a class of chemicals called?

Answer 104

Halogens

Question 105

Metal compounds typically kill microbes by ?

Answer 105

Inactivating enzymes and other proteins

Question 106

Hydrogen peroxide is a more effective germicide on living tissue or inanimate objects?

Answer 106

Inanimate objects