Exam 2 Updated Flashcards
1
Q
What does the suffix static mean?
A
Reduction in the number of the organism but does not kill it completely
2
Q
What does the suffix cidal mean?
A
This type of agent will kill ALL bacteria
3
Q
What are physical agents?
A
- heat
- pressure
- steam
- radiation
4
Q
What is sterilization?
A
A type of decontamination that completely removes and destroys viable microorganisms on inanimate surfaces
5
Q
What is disinfection?
A
A type of decontamination that destroys vegetative microbes (not endospores) on inanimate surfaces
6
Q
What is antisepsis?
A
A type of decontamination that inhibits and destroys vegetative pathogens on living surfaces
7
Q
What is decontamination?
A
the process of decreasing antimicrobial presence in an area or on a surface.
8
Q
What is the most resistant “thing”?
A
A prion
9
Q
What is the least resistant “thing”?
A
A virus
10
Q
What factors should we think about when we want to kill bacteria?
A
- Death Rate
- Characteristics
- Growth
- Chemical environment
- Environmental Factors
- Duration of Exposure
- Mode of Action
- Resistance Factors
11
Q
What is a biofilm?
A
A community of bacteria that coat the surfaces of equipment
12
Q
What are broad spectrum antibiotics?
A
Antibiotics that act against a wide range of disease-causing bacteria
13
Q
What are narrow spectrum antibiotics?
A
Antibiotics that are only effective against a particular/specific group of bacteria
14
Q
What parts of the bacteria do antimicrobial agents target?
A
- Cell wall
- Cell membrane
- Proteins
- Nucleic Acids
15
Q
How is the cell wall affected by antimicrobial agents?
A
EITHER…
The agent will “punch holes” in it and cause it to disintegrate and spill contents
or it will attack the bonds that hold the cell wall together or prevent the wall from forming
16
Q
How is the cell membrane affected?
A
It is diffused which cause it to degrade
17
Q
Which type of soap is bacteria resistant to?
A
Antibacterial hand soap
18
Q
What type of shape are proteins?
A
They are 3D shapes and if they do not have the same 3D shape, they will not function properly.
19
Q
What is a native state protein?
A
A protein that is normal (correct 3D shape)
20
Q
How are proteins affected?
A
They can either be denatured (by heat, pH, etc) and cause it to unfold
They cant chemically interfere with the protein and cause it to have a different shape
Their active sites could also be blocked
21
Q
What can proteins help with?
A
Breaking down glucose, copy DNA, etc
22
Q
What is one indirect way to affect proteins?
A
We can target the ribosomes that make protein. THis is an example of selective toxicity because our ribosomes are larger.
23
Q
What are some physical methods of control?
A
- heat
- filtration
- cold
- dessication
- osmotic pressure
- radiation
24
Q
What is the appropriate temperature and time for sterilizing anything?
A
121 C for 15 minutes
25
Which type of heat is more effective?
Moist heat
26
What happens when we use cold temperatures to control microbial growth?
Microbes will not necessarily die, their growth will simply be slow. Those that benefit from spores may be in their endospore form
27
What is dessication?
The process of removing water from a substance (use it to preserve our foods. We can also combine this with lypholization to freeze dry food
28
What does Radiation do to control microbial growth?
It targets DNA of all organisms
29
What are the 2 types of radiation?
Ionizing (gramma and x rays) and non-ionizing (UV rays)
30
What is ionizing radiation?
When it forms an ion and causes breaks in the DNA
31
What is non-ionizing radiation?
When an ion is not formed but causes inappropriate bonds to form
32
How are UV rays related to nonionizing radiation?
It will cause 2 thymines to bond together (AKA thymine dimer). When enzymes read the DNA, it will cause it to stop because the strand will be lifted.
33
What are the 3 levels of germicides?
High, Intermediate, and Low
34
What is a high level germicide?
A chemical agent that will kill everything (including endospores). They are way too toxic for us.
35
What is an intermediate level germicide?
A chemical agent that is pretty effective but may not kill spores
36
What is a low level germicide?
A chemical agent that only kills vegetative cells.
37
What is the kirby bauer test?
A test that helps us determine the effectiveness of an antibiotic or cleaning agent
38
What are the steps for performing a kirby bauer test?
We take a type of bacteria and create a streak plate. We then insert disks that are infused with the test agent. After a few days, we check for signs of growth.
39
What are the 6 important elements that our bodies need?
CHNOPS
| Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and sulfur
40
What is glycolysis?
It is the first step in making energy for us and it breaks down glucose in order for the carbons to be transported into the mitochondria
41
What is Krebs Cycle?
The second step in creating energy for us. The carbons that are in the mitochondria are modified in order for it to harvest electrons from the carbon bonds.
42
What is the Electron Transport Chain?
The last step in creating energy for us. This is a series of reactions that work to produce ATP.
43
Where does the energy production cycle (glycolysis, krebs, electron transport) occur in bacteria?
Since they do not have membrane bound organelles (and mitochondria is one), all of this process occurs in their cell membrane
44
How much ATP do we produce in the energy production cycle?
36-38 ATP
45
Our cells use the energy production cycle when ____ is present
Oxygen
46
Bacteria that do not rely on oxygen require energy, what process do they use?
Lactic acid fermentation
47
What are the only ways we make energy?
Breaking down glucose (energy production cycle) OR lactic acid fermentation
48
What is an exergonic reaction?
Consuming food and releasing energy. Here, a substance is broken down and energy is released
49
What is an endergonic reaction?
In this case, energy is absorbed. 2 substances are put together
50
What are the 3 possible ways to make energy?
In aerobic respiration, we use the energy production cycle
In anaerobic respiration, we will still use glycolysis and Krebs cycle but we cannot use the electron chain because oxygen cannot be used a final electron acceptor. Instead the bacteria can use other elements
Finally, fermentation can be used regardless of oxygen presence/absence.
51
What is bacterial mutualism?
It is a relationship in which every organism benefits from. An example is bacillus polymyxa and p. vulgaris. B.polymyxa gives niacin to p.vulgaris and p.vulgaris gives biotin to b.polymyxa
52
How is nitrate fixed?
Some bacteria can fix nitrate. They take in nitrogen gas, convert it and it makes nitrogen accessible to plants. In return, they receive sugar (food)
53
What is an example of predation?
Bdellvibrio uses e.coli as a food source
54
How are bacteria related to methane?
Cows produce a great amount of methane and scientists have found that red algae has a substance that interferes with their methane production.
55
What factors affect bacterial growth?
- Temperature
- Gases
- PH
- Osmotic Pressure
- Radiation
- Hydrostatic Pressure
- Presence/Absence of other Microbes
56
What is the term for the peak of a graph?
Optimum (the best environment for the bacteria)
57
What is cardinal?
range of values (in a graph) where bacteria remain alive
58
What is a capnophile?
An organism that prefers high CO2 concentration
59
What are the 3 categories when discussing the relationship between bacteria and oxygen?
1. Bacteria that can use it and detoxify it
2. Bacteria that do not rely on oxygen (toxic) and cannot detoxify it
3. Bacteria that do not use it but can detoxify it
60
What are the2 harmful products that form when oxygen is present?
Superoxide anion and Hydrogen peroxide
61
How do bacteria get rid of superoxide anion?
To get rid of superoxide anion, they can use superoxide dismutase (SOD)
It takes the superoxide anion and either converts it into oxygen or h2O2. If it turns to h2o2, catalase can break it down to oxygen gas and water
62
How do bacteria get rid of hydrogen peroxide?
By using the catalase enzyme to break it into oxygen, gas and water
63
What is a free radical?
an uncharged molecule (typically highly reactive and short-lived) having an unpaired valence electron.
64
What is an obligate aerobe?
An organism that grows at the top of the media because it cannot survive with oxygen.
65
What is a possible risk of using oxygen as a final electron acceptor?
There is a possibility of free radicals (which can kill them). They can tear their cell membranes, and cause breakage in the DNA.
66
What can neutralize free radicals?
SOD and catalase
67
What is an obligate anaerobe?
An organism that grows at the bottom of the media because it cannot survive with oxygen.
68
What is a facultative aerobe?
An organism that grows throughout the media but is more concentrated at the top because it can use oxygen for energy (not required). It must be able to neutralize radicals because of possible oxygen exposure
69
What is microaerophile?
An organism that grows right below the surface. They
| prefer lower amounts of oxygen.
70
What is aerotolerant?
An organism that do not use oxygen but they can tolerate it. There is equal growth throughout the whole tube.
71
_______ ions make something acidic. ________ ions make something basic.
Hydrogen ions make something acidic. Hydroxide ions make something basic.
72
What is an acidophile?
An acidophile is an organism that lives in acidic conditions.
73
What is a halophile?
A salt loving organism
74
What is an osmophile?
An organism that likes sweet things
75
What is a barophile?
An organism that can withstand hydrostatic pressure
76
How do bacteria duplicate? What is the process called?
Bacteria will initially start with 2 circular chromosomes, then a septum (wall) will form in between the 2 chromosomes. Eventually, the septum will split and divide the bacteria in 2.
77
Why do we use log scale?
To measure the size of bacteria by population.
78
What are the 4 standard phases for bacterial growth?
1: Lag Phase: birth rate is barely greater than death rate.
2: Log Phase:bacteria begin to divide very rapidly
3: Stationary Phase: bacteria has reached its optimum
4: Decline/Death: bacteria begin yo quickly die
79
Will there ever be zero growth for bacteria (in the 4 phases)?
No, there is always SOME growth
80
What is hydrogen peroxide?
It is a radical produced during the breakdown of glucose. It damages bacteria and can kill them if they do not have the catalase enzyme.
81
What is DNA and RNA? What are they made of?
DNA and RNA are nucleic acids that are made of nucleotides
82
What makes up a nucleotide?
Each nucleotide consists of a 5-carbon sugar, phosphate and nitrogenous base
83
What are the DNA bases?
A, T, G, C
84
What are RNA bases?
A, U, G, C
85
What is central dogma?
It describes the process of transcription and translation
86
What is transcription?
When DNA is copied and turned into RNA (specifically mRNA)
87
What is translation?
When the mRNA (from transcription) is translated into a protein.
88
How is the amount of DNA different between eukaryotic and bacterial DNA?
Eukaryotic: 23 pairs of chromosomes
Bacterial: one piece of DNA
89
How is the structure of DNA different between eukaryotic and bacterial DNA?
Eukaryotic: linear
Bacterial: circular
90
How is the packaging of DNA different between eukaryotic and bacterial DNA?
Eukaryotic: have histones to wrap DNA
Bacterial: do not have histones
91
How is the replication process of eukaryotic DNA?
When eukaryotic DNA is replicated, it forms replication bubbles. Enzymes come in and begin to form copies at the bubbles. The bubbles are formed from ORI.
92
What is ORI?
Origin of Replication: a sequence of DNA that directs enzymes to their starting point.
93
How is the transcription/translation of DNA different between eukaryotic and bacterial DNA?
Eukaryotic: Transcription and translation are 2 different phases
Bacterial: Transcription and translation occur at the same time (more efficient)
94
Where do transcription and translation take place in us?
Transcription: nucleus
Translation: cytoplasm
95
What is a promoter?
DNA sequences that define where transcription of a gene begins
96
What is polymerase?
An enzyme that attaches at promoter site and will transcribe the gene
97
What is the difference between promoter in eukaryotes and bacteria?
Eukaryotes have one promoter, one gene. Bacteria have one promoter and multiple genes.
98
What is horizontal gene transfer?
When genetic material is exchanged during the lifetime of an organism
99
What are the 4 types of horizontal gene transfer?
- Conjugation
- Transformation
- Transduction
- Transposable Elements
100
What is conjugation?
The process where one bacterium transfers genetic material to another through direct contact
101
How does conjugation work?
A donor cell will have extra DNA (usually resistance genes). Between donor and recipient there will be a mating bridge connecting them. The donor will make a copy of the extra DNA and give it away.
102
Does conjugation have any species limitations?
No, this type of genetic transfer can occur in all microbes
103
What does conjugation result in?
Diversification because the recipient had a different genetic material than it did to begin with
104
What is transformation?
When nearby cells can accept a piece of DNA from a bacteria that had died (lysis).
105
What is a component cell?
A cell that can take up material from a lysis cell
106
Who is Fredrick Griffith?
A bacteriologist that performed an experiment about the transformation process
107
How was the transformation experiment performed?
Griffith had smooth bacteria (capsule) and gave it to a mouse (dead)
He also had rough bacteria (no capsule) and gave it to a mouse (survived)
He then heat fixed smooth bacteria and gave it to a mouse (lived)
However, once he mixed heat fixed smooth bacteria with rough bacteria, the mouse would die
108
Why did mice die when they were given a mix of heat fixed smooth bacteria and rough bacteria?
Because the rough cells picked up the virulence factor. In other words, they picked up the genes from the dead smooth cells to produce a capsule
109
Why do capsule bacteria kill us?
Because our immune cells cannot recognize it
110
What is bacteriophage?
Viruses that affect ONLY bacterial cells, not us.
111
What is the first step in viral infections of bacterial DNA?
A phage will land on a bacterial cell and inject its genetic information into the cell
112
What is the second step in viral infections of bacterial DNA?
Since the viral genome is in the cell, the bacterial cell will go into a synthesis phase. In other words, it will make new copies of viral DNA and of structural parts of the virus. Eventually, the virus parts will be assembled
113
What is the third step in viral infections of bacterial DNA?
The bacterial cells will either lyse or the viruses are going to be sent out through exocytosis
114
What is transduction
In step 2 of viral infections of bacterial DNA, an error of packaging viral genome, can cause bacterial genome to be packag5ed instead. If this occurs, it will stop the virus from doing it's job and cause an infection. It will still infect other cells but instead it will inject bacterial DNA. In other words it will is the process by which foreign DNA is introduced into an eukaryotic cell by a virus.
115
What is the main idea of transposable elements?
There are jumping genes (segments of DNA) that code for enzymes which will cut out the segments and insert them in other cells
116
Who proposed the transposable element theory?
Barbara McClintock
117
What is the similarity between conjugation, transduction, transformation, and transposable elements?
Each process results in the cell having a different genetic material than what they started with.
118
What is the ames test?
A useful tool that determines the toxicity of chemicals, antibodies, etc.
119
What bacterial element is traditionally used for the ames test?
Salmonella
120
What are histidines?
It is an alpha amino acid that is used in the biosynthesis of proteins
121
Does salmonella produce histidine?
No, they need histidine to be in their environment to survive
122
What is the steps of the ames test?
There is a control plate and a test plate. The control plate has a minimal media and no histidines. The test plate had the same contents but there will be a test agent to see it's ability for mutagenesis. Theoretically, salmonella should die because it need histidines and no media has it.
123
What is minimal media?
Media with no nutrients
124
What is mutagenesis?
a process by which the genetic information of an organism is changed, resulting in a mutation.
125
According to lecture, what occurred to salmonella in the control plate?
The control plate had 2 colonies. This means that 2 cells somehow survived the lack of histidines through a spontaneous mutation.
126
According to lecture, what occurred to salmonella in the test plate?
There are far more colonies and it means the test agent is a mutagen. This means it causes high rates of mutation for bacteria cells. If the test agent causes mutation, we will know NOT to use the product
127
What is trisphosphate?
A chemical that was used in kids pijamas and after tested (ames), it was a carcinogen
128
What is the overall main purpose of the ames test?
To tell us whether a substance is dangerous
129
What type of genetic material can viruses have?
It can have double stranded DNA, single stranded DNA, single stranded RNA, double stranded RNA, and +/- single stranded RNA
130
What was the very first virus to be characterized?
Tobacco Mosaic Virus
131
What is positive sense RNA?
It is RNA that just came from the virus and can directly go to the ribosome to make a protein
132
What is negative sense RNA?
RNA that came from the virus but is not readable. It must first become positive sense RNA so that it can then go into the ribosome
133
What are retroviruses?
Viruses that oppose central dogma
134
How do retroviruses work?
They start with RNA and convert it into DNA the DNA goes through transcription and translation and build new proteins/genomes.
135
What enzyme do retroviruses use?
Reverse Transcriptase
