1
Q
Define bacterial growth?
A
increase in number of cells in population - reproduction
2
Q
Why is bacterial growth important?
A
while one pathogenic bacterium cant hurt you a large growing population can
3
Q
What environmental factors effect the rate of bacterial growth?
A
temperature O2 Ph osmotic pressure
4
Q
What effects the rate of bacterial growth?
A
generation time of species / availability of resources / interactions with other organisms
5
Q
Define generation time?
A
amount of time it takes from completion of one cell division until completion of the next (genetically defined for each species and ranges min- hrs) bacteria reproduce via asexual binary fision
6
Q
Where do Psychrophiles thrive?
A
Very COLD temps
7
Q
Where do Mesophiles thrive?
A
Moderate temp (body temp)
8
Q
Where do Thermophiles thrive?
A
HOT temps
9
Q
Where do Hyperthermophiles thrive?
A
VERY HOT (near boiling) temp
10
Q
If temp exceeds optimal what happens to bacterial growth?
A
proteins denature and lose their function causing bacteria to die (easy to do and die fast)
11
Q
If temp drops below optimal what happens to bacterial growth?
A
growth slows or stops but death does not always occur
12
Q
Explain “bacteria are also classified by O2 requirements”
A
O2 is a “toxic” compound due to oxidation effect / organisms that “detoxify” O2 can tolerate but those that cannot are inhibited or killed
13
Q
If a bacteria likes a low PH (<6) they are classified as?
A
Acidophiles
14
Q
If a bacteria likes a medium PH (6-8) they are classified as?
A
Neutrophiles
15
Q
If a bacteria likes a HIGH PH (>8) they are classified as?
A
Alkaiphiles
16
Q
Why are bacteria classified by salinity?
A
the solute’s effect on osmotic pressure so there is a range where they thrive and struggle
17
Q
What salinity do halophiles thrive in?
A
high salt concentrations (usually ocean)
18
Q
What salinity do halotolerant bacteria thrive in?
A
don’t need salt but can survive a lot of salt (everywhere)
19
Q
What is the element C used for?
A
Proteins lipids nucleic acids carbohydrates ATP
20
Q
What is the element H used for?
A
Proteins lipids nucleic acids carbohydrates ATP
21
Q
What is the element O used in?
A
Proteins lipids nucleic acids carbohydrates ATP
22
Q
What is the element N used in?
A
amino acids nitrogen bases ATP
23
Q
What is the element S used in?
A
some amino acids
24
Q
What is the element P (phosphorus) used in?
A
Nucleic acids membrane lipids ATP
25
What is the element K used in?
Enzyme function
26
What is the element Mg (magnesium) used in?
Enzyme function
27
What is the element Ca (calcium) used in?
Enzyme function
28
What is the element Fe used in?
enzyme function and electron transport
29
be able to identify what elements are needed for for bacterial conditions
30
Distinguish between growth in nature and growth in the lab
lab is controlled nature is not
31
As
32
What kind of data does bacterial growth in the lab provide?
easy to analyze but “unnatural”
33
What kind of data does bacterial growth in nature provide?
observation but often confounded
34
Population difference between lab and nature
nature has mixed population (interspecies interactions and competition for food) lab is isolated
35
What factors cause variable bacteria growth in nature?
Type /amount nutrients / removal of waste / temp/ presence of competition or preditors/ host immunity
36
Why is there less variable bacteria growth in the lab?
because the conditions can be controlled (temp
37
What is the bacterial growth curve in the lab?
amount of time will vary but all will lag
38
What is a closed system?
bacterial culture in lab where no new nutrients added and waste is not removed
39
What is an open system?
bacterial culture in lab where nutrients are added and waste is neutralized
40
What determines whether a system is open or closed?
media’s consistency (agar or broth) container (plate or tube) purpose (differential media)
41
What goes into selecting a growth media?
type of microbe and what kind of growth desired
42
What are the characteristics of general purpose media?
supports wide variety of growth
43
What are the characteristics of complex media?
complex mix of growth nutrients
44
What are the characteristics of selective media?
ingredients that prevent growth of certain microbes
45
What are the characteristics of Differential media?
provide visual indication that reaction has happened
46
What are the characteristics of Enriched media?
used for microbes found in low numbers esp fastidious microbes
47
Bacterial growth is a ____ system that follows a _____ progression shown on a ______
closed system / standard progression / bacterial growth curve
48
Bacterial growth chart
49
What happens during lag phase?
bacteria prepare for division ( no increase in cell number / ATP and enzymes synthesized / cells grow slightly / media is conditioned by enzyme release)
50
What happens during log phase?
Cell numbers increase exponentially (most susceptible to antibiotics / length of phase determined by ability to synthesize ATP )
51
What happens during stationary phase?
cell division slows (cells die / nutrients limited / waste accumulates)
52
What happens during death phase?
cells die at an exp rate (no more cell division / involution makes identification hard but persistor cells cling to life)
53
Be able to match the vents to specific phase of growth
54
What is the formula for predicting bacterial growth?
Nt=N0 x 2n
55
Explain each part of bacterial growth equation
Nt= total cells over given time / N0= original cell number at start time / 2= number of cells produced with each division/ n= number of divisions over given time
56
How many variables do you need to be able to use the bacterial growth?
two bc you can use it to solve for the missing variable
57
What are the main ways to measure bacterial growth?
direct cell counts
58
59
Response to math 1
000 cells
60
Know steps to doing viable cell count on slide 45 (response or answer is Cfu’s/mL)
61
62
LECTURE 8 - NOVEMBER 6th be able to label bacterial growth curve
63
Why is it important to control microbial growth
prevention and treatment of infectious disease / food industry to prevent spoilage and food-borne illness
64
What are the two main approaches to control microbial growth?
kill the microbes / inhibit growth
65
What is “childbed fever”?
19th century death during childbirth . 30% b/c of poor hygiene (non-sterile practice
66
What did Dr. Ignaz Semmelweis contribute?
observed difference in morality between birthing clinics due to med students (higher- surgery
67
What did Dr. Joseph Lister contribute?
championed the germ theory (made by koch and pasteur) using carbonic acid as antiseptic revolutioning surgery
68
What did Nicolas Appert contribute?
french confectioner basic canning technique for food preservation (sealed containers and heat application)
69
How does the ubiquity of microbes relate to the importance of control?
microbes can easily get into pounds
70
What are the options for controlling microbes?
killing is preferred not always possible/ inhibit growth / stop attachment/ block matrix synthesis - causing them to loose the protective coating /disrupt communication / promote detachment / mechanical removal
71
72
Define Disinfection
reduces microbial movers on inanimate objects through heat or chemical
73
What is the application of disinfection?
medical facilities including lab benches or clinical surfaces and bathrooms
74
Define Sanatization
reduces on inanimate objects to safe public health # vis heat or chemical
75
What is the application of sanitization?
food industry EX: commercial dishwashing
76
What is the difference between disinfection and sanitation?
disinfection used in medical facility/ Sanitization used in food industry
77
Define degerming
reduces microbial numbers on skin through scrubbing with mild chemicals
78
What is the application of Degerming?
handwashing
79
Define antisepsis
reduces microbial numbers on skin or tissues through chemical agents
80
What is the application of antisepsis?
cleaning skin broken through injury and handwashing prior to surgery
81
What is the difference between degerming and antisepsis?
antisepsis is a higher level of degerming
82
Define disinfectant
chemical agent used to disinfect or sanitize inanimate objects
83
What are the characteristics of disinfectant?
not to be used on living tissues / stronger than antiseptics
84
Define antiseptic
chemical agent used for antisepsis or degerming of skin or tissues
85
What are the characteristics of antiseptic?
weaker than disinfectants but can be used on internal tissues
86
Define Germacidal
chemical agent that kills
87
What are the characteristics of germicidal agents?
bactericidal / viricidal and fungicidal agents that target specific microbial groups
88
Define germistatic
chemical genet that inhibits growth
89
What are characteristics of germistatic agents?
bacteriostatic and fungistatic agents that target specific microbial groups
90
Most to least resistant microbes (larger numbers harder to kill than lower numbers)?
Prions
91
92
How do you select an antimicrobial control procedure?
Area to be treated (size location use) / types of microbes present / risk of infection /composition of material to be treated (surgical equipment needs to be sterile so its stainless steel and can go into autoclave or disposable)
93
Why are stethoscopes NOT required to be sterile?
they are non-invasive (they don't go into body and sterilization would destroy them)
94
How does a control agent effect cell walls?
damage cell wall by blocking synthesis or digesting cell wall
95
How does a control agent effect cytoplasmic membrane?
disrupt lipid bilayer of membrane opening it up and allowing destructive chemicals to enter cell and ions to exit cell
96
How does a control agent effect cellular synthesis?
interrupt protein synthesis by ribosomes and those for growth and metabolism preventing reproduction and sometimes causing mutation
97
How does a control agent effect proteins
? Denature proteins removing their function or attach to active sites blocking activity
98
What two categories are antimicrobial procedures divided into?
physical and chemical
99
List physical methods for antimicrobial control procedures
washing / heat/ cold / drying / radiation / filtration
100
Lost chemical methods for antimicrobial control procedures
antiseptics and disinfectants and antimicrobial medications
101
SLIDE 25 -26
102
What are the characteristics of phenolics?
denatures proteins / good for floors but toxic for tissues/ provides residual effect
103
What are the characteristics of heavy metals?
inhibits enzyme activity (silver mercury copper) / some toxic in concentration
104
What are the characteristics of formalin and formaldehyde?
inactivates enzymes / used to preserve specimens / toxic and carcinogenic (causes cancer)
105
What are the characteristics of ozone?
oxidizing agent / used for drinking water treatment / corrosive to metals
106
What is considered to be one of the most effective physical / chemical methods of microbial control?
hand washing with soap because of physical (washing) and chemical (soap) because it is cheap easy and accessible
107
Describe the CDC handwashing procedure
1. Wet hands with running water then turn off tap and apply soap / 2. Lather hands by rubbing hands backpacks between fingers and under nails / 3. Scrub hands for at least 20 seconds / 2. Rinse hands well / 5. Dry hands using clean towel or air
108
How are chemical microbial control methods assessed for effectiveness?
exposing specific microbes to agents soaked into disks which are then incubated and the “zone of inhibition” is examined
109
What determines the type and concentration of chemical methods of microbial control?
application (are they for wounds
110
Why is special care required for food preservation?
food is full of nutrients favoring microbial growth and the methods can’t be toxic (if microbes can choose between you the wall or food they will choose the food because it does not have an immune system like you and has endless fuel)
111
What are chemical preservatives in food (natural or chemical)?
acids (low pH inhibits growth) / salt or abundant sugar (creates hypertonic environment by disrupting osmolarity) / chemicals (inhibits sporulation
112
What physical condition can help preserve food (cold)?
Refrigeration: Low temp (0-5°C) storage SLOWS growth but does not kill the microbes / Freezing (-20°C) STOPS growth and kills ~50% microbes but once food is thawed growth resumes
bio 150
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