Ch 6 - Microbial Nutrition and Growth

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what does growth refer to in an organism

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101 Terms

1

what does growth refer to in an organism

increase in size of organism

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2

what does growth refer to in microbes

an increase in the population size

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3

how do bacteria reproduce

asexually through binary fission

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4

how do eukaryotic cells reproduce

through mitosis

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5

how do yeast cells reproduce

asexually through budding

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6

what is a a batch culture

it means theres only so much nutrients available for the bacteria to take in

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7

what are the phases, in order, for the bacterial growth curve

lag phase, log phase, stationary phase, and death phase

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8

what is the lag phase

the introduced number of bacterial cells are gearing up for replication

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9

what is the log phase

the bacterial cells are reproducing

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10

what is the stationary phase

the bacterial cells begin to run out of nutrients and are giving off by-products

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11

what is the decline phase

the cells die, but their are some viable cells for a few days

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12

what does the slope of the log phase tell us

the growth rate

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13

what does the slope of the death phase tell us

the death rate

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14

the slopes from the bacterial growth curve should be the ________, just one ___________ and one ________________

same, positive, negative

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15

what two ways do we get bacterial cells to a way that we can count

serial dilutions and a standard plate count (SPC)

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16

what is a serial dilution

diluting out concentrated bacterial cultures to get managable numbers or something we can count

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17

what is a standard plate count (SPC)

counting the number of colonies after a serial dilution

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18

what method do you use to determine the number of bacterial cells in a culture

a pour plate method

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19

what is the acceptable range of colonies per plate for a pour plate when counting large colonies

30-300 colonies per plate

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20

what is a viable count

the total number of live cells being counted at a given time

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21

what are the two ways to preform a direct or total cell count

counting the isolated colonies or doing a cell count through cytometry

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22

what is cytometry

it uses a machine that dilutes the cells so you can directly count them

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23

what does an indirect count mean

you’re not looking for a number just at the gowth of colonies

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24

what are the two ways you can indrectly count bacterial colonies

through turbidity or dry weight

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25

how is tubidity used to indirctly count colonies

if the tube is cloudy then their are micribes growing in it

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26

if their is not a lot of light shining through a tube that has tubidity in it what does that mean

their is high tubidity meaning the population size is larger

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27

if their is a lot of light shining through a tube with turbidity in it what does that mean

their is low turbidity meaning the population size is smaller

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28

what does dry weight measure in bacteria

the number of biomass in the colonies

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29

what is a physical influence of microbial growth

temperature

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30

what are the four types of microbes that grow at different temps

psychophiles, mesophiles, thermophiles, and extremthermophiles

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31

what is the temperature range of psychrophiles

less than 20 degrees C

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32

what type of microbes are psychrophiles

food spoilage because they live a fridge temperatures

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33

what is the temperature range for mesophiles

15-45 degrees C with 37 C being optimum

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34

what type of microbes are mesophiles

normal flora, pathogens, E. coli

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35

why are mesophiles medically important

because they live at room temperature

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36

what temperature do thermophiles live at

60 degrees C

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37

what temperature do extremthermophiles live at

65-100 degrees C (near the point of boiling water)

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38

what is an example of an extremthermophile

archaea

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39

why do many pathogens not like to be warm

they become denatured

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40

what is a chemical influence of growth

oxygen influences

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41

what are the two categories of oxygen influences

aerobes and anaerobes

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42

what is the difference between aerobes and anaerobes

aerobes is with oxygen anaerobes is without oxygen

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43

what is an obligate aerobes

it thrives in our oxygen levels

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44

what is a microaerophilic

likes smaller or lower amounts of oxygen

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45

what are the two types of aerobes

obligate aerobes and microaerophilic

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46

what are the three types of anaerobes

obligate anaerobes, facultative anerobes, and aerotlerant anaerobes

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47

what is an obligate anaerobe

oxygen is toxic to them

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48

what is a facultative anaerobe

it can grow without oxygen but can also grow with it

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49

what is an aerotolerant anaerobe

it tolerates oxygen and can go without but doesnt use oxygen for anything

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50

what are the two clinical anerobic bacteria

clostridium and bacteriocides

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51

what is thioglycolate medium used for

it is a reducing agent that decreases the amount of oxygen so we can determine what type of microbe is present

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52

where do obligate aerobes grow at in thioglycate medium

at the surface

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53

where do microaerophiles grow at in thioglycate medium

below the surface but not very deep

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54

where do obligate anaerobes grow at in thioglycate medium

only at the deep bottom part of the tube

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55

where do facultative anaerobes grow at in thioglycate medium

all throughout the tube

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56

what is a biofilm

a collection of mixed microbes trapped in the sticky solution called biofilm

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57

what are some examples of a biofilm

dental plaque, pseudomembranes, and necrosis or flesh eating disease

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58

what form of medication doesn’t normally work on biofilms

antibiotics

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59

what is sibling warfare

when two line inoculations are prefromed on a plate and the microbe sbegin to grow away from each other

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60

what is the point of using selective and differential media

to isolate and ID bacteria

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61

certain microbes can be selective for what ______ they grow at

pH

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62

fungi grow best at what pH levels

lower pH levels such as 5-6

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63

bacteria grow best at what pH levels

closer to nuetral or even a little alkaline/basic

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64

what type of medium is blood agar

enriched and differential

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65

what is blood agar enriched with

RBC’s from sheep

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66

how is blood agar differential

from hemolysis

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67

what is carbohydrate fermentation used for

to determine different types of bacteria/charcteristics

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68

what is glucose common in

many bacteria

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69

what is lactose common in

enterics

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70

what is mannitol common in

some staph bacteria

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71

acid fermentators cause a ___________

low pH

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72

if their is a low pH in the medium what is caused

a color change in the growth medium (ex from red to yellow)

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73

what is a durham tube

a test tube that is in a liquid broth medium and is inverted and filled with the same medium, it there’s CO2 the interior tube will start to bubble

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74

what is a candle jar used for

it reduces oxygen levels but doesn’t make the enviorment completely anerobic

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75

what is an anerobe jar

it makes the enviorment completely anaerobic

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76

what microbes is a candle jar used for

microaerophiles

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77

what type of microbe is an anaerobe jar used for

obligate anaerobes such as clostridium and bacteroides

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78

what does a candle jar, anaerobe jar, and thioglycate medium do

they control the oxygen levels in a microbes enviorment

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79

viruses can not be cultured on _________________________

artificial media because there’s no cells

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80

why do some bacteria require special growth media

because they are harder to culture

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81

many bacteria are fastidious meaning

they have complex nutrient requirements

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82

what type of media is used for fastidious bacteria

enriched media

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83

what are the two types of enriched media

choclate agar and blood agar

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84

what is chocolate agar

it is enriched with sheeps blood but the RBC’s are lysed and the released hemoglobin turns it a brown color

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85

major bacteria used on enrched media

haemophilus influenzae and neisseria gonorrheae

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86

what type of media is used for non-fastidious bacteria

general purpose media like nutrient agar

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87

multipurpose media is divided into

primary isolation media and diagnostic media

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88

what is primary isolation media used for

to isolate specific bacterial types, genera and species/strains

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89

what are the two types of primary isolation media

selective media and selective/differential media

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90

what is the function of selective media

it prevents the growth of some bacterial types while allowing growth of others

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91

what are the two types of selective/differential media

EMB and MAC

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92

what does EMB stand for

eosin methylene blue

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93

what is EMB selective for

gram negative bacteria

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94

what is EMB selective against

gram positive bacteria

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95

what is EMB differential for

lactose fermentation

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96

if their is a cloudy pink/red color on an EMB plate that means

the bacteria is lactose positive

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97

if there is a green, metallic sheen on an EMB plate that means

there is strong lactose fermentation (ex E.coli)

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98

what does MAC stand for

MacConkey

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99

an MAC plate has the _________________________ as an EMB plate

same properties

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100

what does lactose fermentation look like on an MAC plate

dark pink/red

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