Lab Exam 2

Question 1

What does pH measure?

Answer 1

How acidic or basic a solution is based on how many hydrogen ions the solution contains

Question 2

Acidophilus

Answer 2

Microbes that grow well at or below pH 5.5

Question 3

Neutrophiles

Answer 3

Organisms that grow well between 5.5 and 8.5

Question 4

What group do most human pathogens fall into? Why?

Answer 4

Neutrophiles because the human body has a pH between 7.2-7.4

Question 5

Alkalophiles

Answer 5

Organisms that live above pH 8.5

Question 6

Why do medical laboratory facilities use media that contains buffers?

Answer 6

since the end product of many types of metabolism are acidic, this allows the pH of the media to stay stable as the microorganisms grow and divide

Question 7

What is an example of common buffer systems that can alternate between weak acids and their conjugate bases?

Answer 7

Phosphate systems and bicarbonate systems

Question 8

What are the biggest factors effecting which group the bacteria fall in?

Answer 8

1) Can they do respiration?
2) can they do an anaerobic method of energy production like anaerobic respiration and fermentation?
3) does the bacteria have the enzymes like catalase or superoxide dismutase to handle/breakdown O2, and its toxic derivatives?

Question 9

What are the oxygen conditions and bacterial growth for Obligate Aerobes?

Answer 9

O2 requirements: Needs
Metabolism Type: Aerobic Respiration
Enzymes to handle reactive oxygen: Yes

Question 10

What are the oxygen conditions and bacterial growth for Microaerophiles?

Answer 10

O2 requirements: Needs low level
Metabolism Type: Aerobic Respiration
Enzymes to handle reactive oxygen: Yes, but low level, can be damaged by high O2

Question 11

What are the oxygen conditions and bacterial growth for Faculative anaerobes?

Answer 11

O2 requirements: Grows better with O2, can grow without O2
Metabolism Type: Aerobic respiration, anaerobic respiration
Enzymes to handle reactive oxygen: Yes

Question 12

What are the oxygen conditions and bacterial growth for aerotolerant anaerobes?

Answer 12

O2 requirements: None, O2 can be present
Metabolism Type: Anaerobic method
Enzymes to handle reactive oxygen: Yes

Question 13

What are the oxygen conditions and bacterial growth of strict anaerobes?

Answer 13

O2 requirements: none! O2 is toxic
Metabolism Type: anaerobic method
Enzymes to handle reactive oxygen: no

Question 14

What is a nonselective enriched media that can grow a wide array of microorganisms?

Answer 14

Thioglycollate broth

Question 15

Media components of thioglycollate broth

Answer 15

1) Yeast extract, digested casein= nutrients for growth
2) Sodium thioglycolate and L-cystine= lowers the amount of oxygen in the media
3) Resazurin= color indicator that is pink when oxidized and colorless when reduced, so it shows there is oxygen when pink. The tube you get should be slightly pink at the top, indicating there is an oxygen gradient going down the media

Question 16

What happens if it is too cold for an enzyme?

Answer 16

It will slow down the rate of chemical reactions

Question 17

Psychrophiles temperature

Answer 17

Minimum C: -10
Optimum C: 15
Maximum C: 20

Question 18

Psychrotrophs temperature

Answer 18

Minimum C: 0
Optimum C: 20
Maximum C: 35

Question 19

Mesophpiles temperature

Answer 19

Minimum C: 15
Optimum C: 20-45 range
Maximum C: 45

Question 20

Thermophiles temperature

Answer 20

Minimum C: 45
Optimum C: 55-65 range
Maximum C: 85

Question 21

Extreme Thermophiles temperature

Answer 21

Minimum C: 55
Optimum C: 85-113 range
Maximum C: 113

Question 22

What is transformation used to describe?

Answer 22

When a microorganism can uptake DNA from its environment

Question 23

What is one mechanism by which bacteria do horizontal gene transfer?

Answer 23

Transformation

Question 24

Are every species of bacteria capable of doing the process of transformation?

Answer 24

NO

Question 25

What do you call cells that are capable of undergoing transformation?

Answer 25

Competent Cells

Question 26

What is an example of cells that do not normally do transformation?

Answer 26

Eukaryotic cells

Question 27

The most successful stable transformations involve genes that are coded for on a ______ because circular DNA is less likely to be degraded

Answer 27

Plasmid

Question 28

What is a plasmid?

Answer 28

A small piece of double stranded DNA that can autonomously replicate independent of the host chromosome1

Question 29

What is an Operon?

Answer 29

A group of features coded for within the DNA and is a functional genetic unit in a prokaryote

Question 30

What are the parts of the arabinose operon?

Answer 30

the promoter and the araC gene

Question 31

What is a promoter?

Answer 31

The DNA sequence/region where the RNA polymerase binds

Question 32

Possible outcomes for genetic engineering when cloning a gene: This is the outcome: Transformation did not take place What would a plate containing ampicillin look like?

Answer 32

No growth on the plate

Question 33

Possible outcomes for genetic engineering when cloning a gene: This is the outcome: Transformation did take place, but insertion of the gene into the multiple cloning site situated in the middle of the “color indicator” gene was faulty What would a plate containing ampicillin look like?

Answer 33

Growth will take place on the plate, and the colonies will have color/fluoresce

Question 34

Possible outcomes for genetic engineering when cloning a gene: This is the outcome: Transformation did take place, AND gene successfully inserted into the middle of the “color indicator” gene What would a plate containing ampicillin look like?

Answer 34

Growth will take place on the plate, but they will be white/cream colored and not fluoresce as the gene that produces color was interrupted

Question 35

Cardinal Temperature for Thermophiles

Answer 35

Adapted to temperature greater than 45 degrees C

Question 36

Cardinal temperature of Obligate Thermophiles

Answer 36

Will not grow at a temperature less than 40 degrees C

Question 37

Cardinal temperature of Faculative Thermophiles

Answer 37

Will grow below 40 degrees C

Question 38

Cardinal temperature of Extreme Thermophiles

Answer 38

Grow best above 80 Degrees C

Question 39

How does the internal environment of bacteria change based on their external environment conditions?

Answer 39

Regardless of their habitat, bacteria maintain a near-neutral internal environment

Question 40

Why are buffers added to growth media?

Answer 40

To maintain equilibrium

Question 41

Where will an obligate aerobe grow in a fluid thioglycollate medium?

Answer 41

Will grow at the top of the media where oxygen is most plentiful

Question 42

Where will facultative anaerobes grow in a fluid thioglycollate medium?

Answer 42

Will grow throughout the medium but will appear denser at the top

Question 43

Where will an obligate anaerobe grow in a fluid thioglycollate medium?

Answer 43

Will only grow in the lower regions of the medium (least amount of oxygen)

Question 44

Where will aerotolerants grow in a fluid thioglycollate medium?

Answer 44

Will grow uniformly throughout the medium

Question 45

(EMB plate) Selective and differential mediums have what effect on gram + organisms?

Answer 45

They inhibit their growth

Question 46

(EMB plate) In a Selective and differential medium, what is the enteric based on fermentation for Non-lactose fermenters?

Answer 46

Normal colored colonies

Question 47

(EMB plate) In a Selective and differential medium, what is the enteric based on fermentation for Vigorous lactose fermenters?

Answer 47

Dark purple to black colonies

Question 48

(EMB plate) In a Selective and differential medium, what is the enteric based on fermentation for less aggressive lactose fermenters?

Answer 48

Pink to dark purple colonies

Question 49

What does E. coli look on an EMB plate?

Answer 49

Dark colonies with metallic green sheen

Question 50

What does Enterobacter/Klebsiella look like on an EMB plate?

Answer 50

Pink to dark purple colonies

Question 51

(HEA plate) How does the selective and differential medium affect the growth of gram + organisms?

Answer 51

It inhibits the growth

Question 52

(HEA Plate) What color do enterics that ferment 1 or more carbohydrate turn?

Answer 52

Yellow or salmon colored

Question 53

What is an HEA plate designed to do?

Answer 53

Isolate salmonella and shigella from other enterics

Question 54

What color is Salmonella on a HEA plate?

Answer 54

Black colonies

Question 55

What color is Shigella on a HEA plate?

Answer 55

Green colonies

Question 56

What color is categorized as other coliforms on an HEA plate?

Answer 56

Yellow or salmon colored colonies

Question 57

What is araC?

Answer 57

A binding protein that attaches to the promoter and functions as an on/off switch

Question 58

What are the parts of the arabinose operon?

Answer 58

- Promotor (Pbad) - Three structural genes (araB, araA, and araD) - code for enzymes used to digest arabinose - araC

Question 59

Bacteriophage Tr4 and ΦX174 infect what?

Answer 59

E. coli

Question 60

What is Tr4?

Answer 60

A Double stranded DNA phage

Question 61

What is ΦX174?

Answer 61

A Single stranded DNA phage

Question 62

What is one of the largest phages and can only undergo a lytic lifestyle?

Answer 62

Tr4

Question 63

What is it called when you compare the bacteriophage sensitivities?

Answer 63

Phage typing

Question 64

What is Bioremediation?

Answer 64

The process of using living organisms to clean up pollution in the environment

Question 65

What color does the presence of Pseudomonas fluorescens turn the indicator? why?

Answer 65

It turns it pink because the byproducts from the reduction of the oil’s carbon compounds reduce the tetrazolium

Question 66

Why is type O the universal donor?

Answer 66

Because there are no antigens that can be recognized by the recipient

Question 67

Why is AB the universal recipient?

Answer 67

Because they have no Abs in their serum

Question 68

Transfusion of blood into a recipient possessing antibodies to one of the donor blood group antigens can result in a…

Answer 68

Transfusion reaction

Question 69

High levels of what may be toxic to the Kidneys causing acute tubular cell necrosis and renal failure?

Answer 69

Hemoglobin

Question 70

Epidemiology

Answer 70

The study of infectious diseases and non-infectious diseases

Question 71

What falls under the category of epidemiology?

Answer 71

Studying the cause of the disease, the prevalence of the disease, and the transmission of disease

Question 72

What is it called when a disease is transferred from animals to humans?

Answer 72

A zoonotic disease

Question 73

What are the routes of transfer of a diesease?

Answer 73

1) inhalation of airborne microbe via droplets nuclei 2) ingestion of contaminated food or water 3) through the bite of an animal 4) direct contact through sexual contact 5) through blood or tissue as in blood transfusion or transplants 6) by the bite of an insect- a vector organism like a tick 7) transfer via an inanimate object (fomite), like your phone or a door knob

Question 74

what does K represent in the prevalence rate and incidence rate equations?

Answer 74

The number of people

Question 75

Point Prevalence equation

Answer 75

Point Prevalence = [ number of existing cases at point to time/size of at risk population] * K

Question 76

Incidence Rate equation

Answer 76

Incidence rate = [ number of new cases in a time period/size of at-risk population at midpoint of time period]*K

Question 77

What are the largest majority of microbes found in the soil?

Answer 77

Saprophytes

Question 78

What are Saprophytes?

Answer 78

Beneficial microorganisms that can break down organic matter to enrich the soil

Question 79

What are some reasons to test the soil?

Answer 79

- To test for fungal plant pathogens - Health officials might want to know if there is contamination of an area by fecal bacteria or human pathogenic bacteria

Question 80

What is used to grow Actinomycetes bacteria?

Answer 80

Glucose Yeast Extract Agar (GYE agar)

Question 81

What is a genera non-selective type of media that can grow a wide variety of microorganisms?

Answer 81

Tryptic (Trypticase) Soy Agar (TSA)

Question 82

An agar used to grow fungi

Answer 82

Sabouraud Dextrose Agar (SDA)

Question 83

What is the second leading cause of death for children under the age of 5

Answer 83

diarrheal disease

Question 84

What are coliforms?

Answer 84

Rod-shaped gram-negative, non sore forming and motile or non motile bacteria that can ferment lactose with the production of acid and gas when incubated at 35-37 degrees C

Question 85

What are coliforms that live in the digestive tracts of animals?

Answer 85

Fecal coliforms

Question 86

What does the most probable number (MPN) test determine?

Answer 86

The number of total coliforms in a water sample

Question 87

What are the three parts an MPN test is divided into?

Answer 87

Presumptive, confirmed, and completed tests

Question 88

what type of bacteria is a lactose tryptose broth selective for due to the presence of lauryl sulfate?

Answer 88

Gram negative

Question 89

The more diluted the sample, the likelihood of the broth being inoculated ___________, resulting in no growth

Answer 89

Decreases

Question 90

The more ______ the sample, the less likely you are to have gas production from that subset of microorganisms

Answer 90

Dilute

Question 91

Why do we need to be able to test how sensitive a strain of bacteria is to a particular antibiotic?

Answer 91

Because not all antibiotics naturally work against all types of bacterial infections

Question 92

Are gram positive or gram negative bacteria harder to kill? Why?

Answer 92

Gram negative because of their outer membrane

Question 93

What is the Kirby-Bauer disk diffusion method?

Answer 93

Spread bacteria on an agar plate to grow a lawn and put an antibiotic-infused disk in the center

Question 94

Bacteriostatic definition

Answer 94

Inhibition of growth A substance that prevents the multiplying of bacteria without destroying them

Question 95

Bactericide definition

Answer 95

A substance which kills bacteria

Question 96

What are the clear rings around a Kirby-Bauer disk called?

Answer 96

Zones of inhibition

Question 97

What kind of agar is used for a Kirby-Bauer test?

Answer 97

Mueller-Hinton agar