Lecture Exam 2 Flashcards
(95 cards)
1
Q
Mesophiles
A
25 degree C to 40 degrees C
2
Q
Thermophiles
A
50 degrees C to 60 degrees C
3
Q
Extreme thermophile
A
Greater than 90 degrees C
4
Q
Hyper thermophiles
A
Greater than 100 degrees C
5
Q
Psycrotrophs
A
20 degree Celsius to 30 degrees Celsius
Can sometimes cause issues with food storage
6
Q
Psychrophiles
A
-10 degrees Celsius to 15 degrees Celsius
7
Q
Bacteria optimum pH
A
6.5-7.5
8
Q
Acidophiles
A
Bacteria that like the pH of below 4.0
9
Q
Fungi pH
A
More tolerant to 5.0-6.0
10
Q
Plasmolysis
A
Shrinkage of the cell’s cytoplasm
11
Q
Halophiles
A
Salt loving organisms
12
Q
Carbon
A
The structural backbone of living matter
Half the dry weight of a typical bacterial cell
Growth medium needs a carbon source
13
Q
Nitrogen
A
Required for protein synthesis
Source- organic= protein
Inorganic = nitrate or ammonia
14
Q
Nitrogen fixation
A
Use gaseous nitrogen directly from the atmosphere
Can only be performed by prokaryotes (rhizobium and Cyanobacteria)
15
Q
Sulfur
A
Used to synthesize sulfur-containing amino acids and vitamins such as thiamine and biotin
Source: sulfate and hydrogen sulfide
16
Q
Phosphorus
A
Essential for synthesis of nucleic acids and phospholipids of the cell membrane.
Found in ATP
Source: phosphates
17
Q
Oxygen
A
About 20% of the environment
18
Q
Obligate aerobe
A
Require oxygen to live
19
Q
Facultative anaerobes
A
Can grow with or without oxygen
20
Q
Obligate anaerobes
A
Only grow without oxygen
21
Q
Aerotolerant anaerobes
A
Doesn’t need oxygen but can grow with it
22
Q
Microaerophiles
A
Just enough oxygen
Low concentration of oxygen
23
Q
Superoxide O2- (extra electron)
A
Oxidizes organic molecules
“Burns” them
24
Q
Superoxide dismutase
A
Enzyme produced to destroy superoxide
25
Catalase
An enzyme that breaks down hydrogen peroxide
26
Vitamins
Any organic compound that the microbe (or you) cannot synthesize
Vitamin C is needed and we get it from citrus and other foods
27
Solidifying agent
Agar
28
Agar
Polysaccharide from seaweed
Most bacteria cannot digest it
Melts at 100 degrees C and solidifies at 45 degrees C
29
Defined media
Composition is known exactly (because you mix it)
Useful for nutritional studies
Some microbes are “fussy” (fastidious)
30
Complex media
Based on extracts from plants, yeast, or animal tissues.
| Composition varies, unknown (tryptophan soy agar)
31
Anaerobic methods
Air tight jars (anaerbe jars)
| CO2 goes up, O2 goes down
32
Obligate parasites
Only grow on host
33
Selective media
Promotes growth of one kind of microbe, while inhibiting others
34
Differential media
Many kinds of microbes will grow, but you can tell them apart
35
Preserving microbes
Short term: 1-3 months, grow on slants, into fridge at 4 degrees Celsius
Long term: years, deep freeze (-80 degrees Celsius, liquid nitrogen), lyophilization (freeze drying) (stored at room temp)
36
Binary fission
Reproduction of bacteria
37
Generation time
The time required for a cell to divide
E. Coli=20 minutes
Most species: 1-3 hours
38
Exponential curve
‘J shaped’ curve
39
Plate counts
Known volume of innoculum
Spread it uniformly over a plate
Incubate it for 24 hours
Count colonies (each colony represents 1 cell from innoculum)
Measures live cells only
Colony forming units- what plate counts are reported as
40
Serial dilution
A process of diluting the original innoculum several times
41
Bacterial growth curve
Shows growth of cells over time
42
The lag phase
Period of little or no cell division
43
The log phase or exponential growth phase
The cells begin to divide and enter a period of growth
44
The stationary phase
Period of equilibrium
45
Carrying capacity
The number of of organisms that an environment can support
46
The death phase or logarithmic decline phase
The number of deaths eventually exceeds the number of new cells formed
47
Direct counts
A measured volume of a bacterial suspension is placed within a defined area on a microscope slide
48
Hemacytometer or Petroff-Hausser
Used in direct microscopic counts
| Disadvantage: counts love and dead cells
49
Indirect methods
Measures turbidity
50
Spectrophotometer
The instrument used to measure turbidity
51
Dry weight
Don’t worry about the cell number, just measure the weight
52
Metabolic activity
Measures oxygen consumption
Measures CO2 production
Measures glucose consumption
Measures ATP production
*requires standard curve
53
Bacteriocidal
Killing growth
54
Bacteriostatic
Stopping growth
55
Disinfectant
Apply to inanimate objects (bleach on the tables)
56
Antiseptic
Apply to living tissue (washing hands)
57
Sterilization
An absolute or complete destruction of all life
58
Degerming
Mechanical removal, rather than killing, of most microbes in a limited are
59
Sanitized
Lower microbial counts to safe public health levels and minimize the chances of disease transmission from one user to another
60
How to kill?
- disrupt plasma membrane
- denature proteins
- denature DNA and RNA
- heat: wet heat is more effective(autoclave) standard: 121 degrees Celsius at 15 psi for at least 20 minutes. (Media, solutions, glassware and tools)
Dry heat: ovens at 170 degrees Celsius for at least 2 hours (glassware and tools)
61
Pasteurization
HTST- High Temperature Short Time (doesn’t sterilize) 72 degrees Celsius for 15 seconds, classic
UHT- Ultra High Temperature (close to sterile) newer, 140 degrees Celsius for 3 seconds (74 to 140 to 74 degrees Celsius(5 seconds))
62
Filtration
Very small pore size in plastic membrane
0.5 nanometers to 0.01 nanometers
Used to sterilize Heat sensitive fluids
63
Radiation
Kills microorganisms of two types: ionizing and nonionizing
64
Ionizing radiation
Gamma rays, X-rays, and high energy electron beams
| Has a wave length shorter that that of nonionizing
65
Nonionizing radiation
Has a wave length longer than ionizing radiation
| Best example is UV light
66
Heavy metals
Silver and mercury- poison enzymes (bind to protein)
| They put silver nitrate on infants eyes
67
Phenolics
Joseph lister
- Phenol: disrupts plasma membrane and denatures proteins, mostly used as a disinfectant since its harsh on living tissue; can be an antiseptic
- “Quats”: quaternary ammonium compounds
- cepacol: disinfectant in hospitals
68
Halogens
```
Iodine
Bromine: can be an outdoor water purifier
Chlorine
Oxidizers
Antiseptic or disinfectant
```
69
Oxidizers
Denature proteins
Oxygen containing compounds
O3: Ozone (water treatment)
H2O2: hydrogen peroxide
Very effective against anaerobic microbes
Benzoyl peroxide: common ingredient in acne medications
70
Aldehydes
```
Highly effective disinfectants
Denature proteins
Not used on living tissue
Most common: formaldehyde
Sterilize instruments
```
71
Alcohol
Denature proteins
Disrupt plasma membrane
Mainly used as a disinfectant
Not good in wounds
72
Gas sterilants
Ethylene oxide
Used on some plastic medical equipment
Used on plastic petridishes
Used on the rovers sent to Mars
73
Antibiotics
Drugs: internally take (most of the time with the exception of Neosporin)
Inhibit growth or kills it
Effective in low concentration
Considered a natural substance (originally)(strict)
Broad: include synthetic
74
Central dogma
DNA to RNA to Protein to Phenotype
75
Genetics
All your cells have the same DNA even though they are all very differnet
76
Jacob and Monad
Worked with E. Coli
Discover Lac Operon
Monad was a member of the French resistance during WWII
77
Phenotype
Ability to digest lactose
E. Coli lives in the intestines and may or may not see lactose
The lactose digesting enzymes take a lot to make so they are not constantly in the intestines
78
Structural genes
Z, Y, A are lactose digestive enzymes
79
Operator
DNA sequence
80
Promoter
DNA sequence, but it is the binding site for RNS polymerase
81
RNA polymerase
Synthesizes RNS from DNA template
| Enzyme looks for recognition sites
82
Regulator
A gene for depressor protein
83
Genetic recombination
Combing DNS from different individuals
No sex in bacteria
Bacteria can do genetic recombination
3 kinds: transformation, conjugation, and transduction
84
Transformation
The direct uptake of DNA from an environment
Griffith 1928-
Worked with streptococcus pneumoniae
Some strains of s. pneumoniae had a capsule (virulent, severe disease)
Other strains didn’t have a capsule (avirulent, didn’t cause disease)
85
Conjugation
Plasmid- small circular strands of DNA. (Accessory chromosome)
Allows the exchange of plasmids from one cell to another
Can bring unique genes. (Antibiotic resistance)
86
Transduction
Virus transfer of DNA
Bacteria get viruses (bacteria phage)
Protein shell and DNA
87
Taxonomy or systematics
Science of naming and classification
88
5 kingdoms
```
Animalia (eukaryotes)
Fungi (eukaryotes)
Plantae (eukaryotes)
Protista (eukaryotes)
Monera (bacteria)(prokaryotes)
```
89
Luca
The last universal common ancestor
90
Latin bionomial
Genus name (capitalized)
Species name (lower case)
Each one has to be a unique combo
The binomial is always italicized
91
Classification
References: “Bergey’s Manuel of Determinative Bacteriology” 2600 species described in it
92
Criteria
Morphology- shape, size, flagella, capsule
Differential staining- gram and acid fast
Biochemical- fermentation?. Carbon sources
93
Serology
From serum, which is another word for blood plasma and contains antibodies
94
Phage typing
‘Phage’ is short for bacteriophage, which are a category of virus that attacks bacteria
Host specificity- means virus don’t infect all species
95
DNA anaylsis
It’s becoming routine
DNA sequencing
More commonly- DNA identifying with polymerase chain reaction
