Lecture Final Flashcards
(120 cards)
0
Q
Why is the incidences of food poisoning increasing today even though there is more sterile techniques?
A
More reported cases, stronger bacteria
1
Q
What is the infective dose?
A
The number if bacteria required to cause an illness
4
Q
What is the term for inflammation of the stomach, small intestines, or large intestines?
A
Gastroenteritis
5
Q
What is one ya to treat E. Coli?
A
Clostridium difficile
7
Q
What is a differential medium?
A
Allows all growth but causes a color changes where target bacteria is present
9
Q
What is a selective medium?
A
Only allows the growth of a specific strain of organisms
10
Q
What are the properties of MSA (mannitol salt agar)?
A
Selective and differential medium
Salt only allows halophiles to grow
Some use them manninol to produce acid-changes pH
11
Q
What strain of E. Coli can cause kidney failure in small children?
A
E. Coli 0157:H7
12
Q
What does HAACP do?
A
Increases food safety in production lines by aiming to prevent contamination rather than detect contamination
13
Q
Bacteria is ubiquitous, true or false?1
A
True, it can never be completely eliminated
14
Q
What does HACCP stand for?
A
Hazard analysis critical control points
16
Q
What is the effective dose of E. Coli 0157:H7?
A
50 organisms
17
Q
When was the sanitary revolution?
A
Early 1900s
18
Q
What are the two types of medium used to identify the presence of a specific pathogen?
A
Selective medium, and differential medium
19
Q
What are steps that are crucial to food safety?
A
Critical control points
20
Q
What are critical control points?
A
Steps that are crucial to food safety
21
Q
What is a DNA probe
A
Short strands of DNA that are complementary to the genes present in the microbe
22
Q
What is hybridization?
A
The annealing of complementary strands
23
Q
What must be done before probes are added
A
Microbe cells must be lysed to release their DNA
24
Q
What is the gene track system used for?
A
Detecting pathogens in food samples
25
Q
How long does do gene trak system take to compete?
A
24-48 hours
26
Q
What does NaOH do?
A
Separates the DNA from two strands into one (like helicase)
27
Q
What is done after probes are added?
A
A dipstick with a poly T sequence is added
28
Q
What does the poly T sequence do if bacteria is present?
A
Removes DNA strands that have hybridized to both probes
29
What does the ploy T sequence do if no bacteria is present?
Captures unhybridized probes
30
What are the advantages to the Gene Trak System?
Very specific and reduces The time requires for microbe identification
31
What are there disadvantages to Th Gene Trak System?
Requires a lot of time for enrichment and can provide false positives
32
What does real time PCR do?
Combines amplification and probing in one process.
33
What does the quencher flourophone do .
Reduces flouroscence from the reporter when the two are in close proximity
34
What are the two types of flouroscence molecules attached to e probes in TaqMan PCR?
Quencher and reporter
35
What are the problems with PCR?
Does not distinguish between live an d dead cells
36
What does a microarray do?
A technique that allows for the simultaneous detection of expression of thousands of gene
37
What is cDNA and how is it made?
DNA with the introns- copied directly from mRNA
38
How are antibodies produced?
By the immune system
39
What does IgG stand for?
Immoglobulin
40
What are antibodies that are obtained from different B cells
Polyclonal antibodies
41
What are antibodies produced from a cloned hybrid cell?
Monoclonal antibodies
42
What is a hybridoma?
A B cell fused with a myeloma cell
43
What happens to the B cells which remain unfused?
They die
44
The rate of ________________ affects whether or not transcription is completed.
The rate of translation affects whether or not transcription is completed.
45
What are there three levels of regulation of amino acid production in E. coli?
1. Regulation of enzyme activity through feedback inhibition
2. Regulation of transcription
3. Attenuation
46
When does attenuation regulate?
During transcription
47
How many regions does the mRNA transcript contain?
4
48
What happened if the ribosome incorporates trp at section 1 quickly, what happens?
Sections 3 and 4 form a loop and stop transcription
49
What happens if the ribosome stalls at section 1?
Section 3 will bind with section 2 and allow transcription to complete
50
Why can't LAB be be transformed with a pUC plasmid .
1. Because in the pUC plasmid the ampicillin gene cannot be removed and is growing continually in the presence of the ampR gene. This is not allowed by the FDA
2. We do not want an ori site
51
What are stereoisomers?
Molecules that have the same molecular formula and sequence of bonded atoms, but differ in their 3D orientation of atoms.
52
What happens if an excess of proline is present?
Transcription will shut off
53
What are some reasons for the overproduction of amino acids?
1. Flavor enhancers
2. Supplements
3. Sweeteners
4. Parenteral nutrition
5. Industry uses
6. Pharmaceuticals
54
Why don't researchers synthetically create amino acids?
Stereoisomers
55
Why don't microbes produce excess amounts of amino acids?
Waste of energy
56
what is substantial equvalence?
d
57
What is the ci region on the pEM76:ci plasmid?
Is it is the gene we are targeting
58
What does attenuation do?
Controls the rate translation and can either slow it down or speed it up depending on the amount of tRNA
59
What color does S. Marcescens turn on agar?
Red
60
How does S. Marsescens regulate amino acid production?
Feedback inhibition
61
Why does E. Coli need three levels of regulation while S. Marsescens only uses one?
1. Where they grow
| 2. Environments each must adapt to
62
What are osmoprotectants?
Small molecules that help organisms survive extreme osmotic stress
63
Why is S. Marsescens grown in the presence of high salt concentrations?
To make the bacteria produce excess proline in reeder to avoid dehydration
64
What is an isotonic solution?
Equal pressure
65
What is an hypotonic solution?
Higher pressure outside than inside. Water moves into the cell
66
What is hydroponic solutions?
Higher pressure inside the cell than outside. Water moves out of the cell
67
What do the bacteria cells do under conditions of low oxygen?
Produce more glut amine
68
What type of cycle do many bacteria use under aerobic conditions?
TCA cycle
69
No is aspartame produced?
Fumarate + ammonia + asparate =asparate
70
why are the benefits to making aspartate chemically?
1. Fumarate and ammonia are cheap
2. Purification of aspartate is easy
3. No growth media
71
What's are osmoprotectants and how do thy work?
Overproduce an amino acid in order to equal out osmotic pressure in and out of cell to prevent dehydration
72
What conditions are required to overproduce glutamine from C. Glutamicium
Low oxygen and low biotin levels while growing colony on molasses
73
what is epigenetics?
the study of changes in phenotypes or gene expression caused by factors other than the DNA
74
what is genetic imprinting?
the genetic phenomenon in which certain genes are expressed in a parent-of-origin-specific manner
75
what is maternal imprinting?
the gene from the mom is inactive
76
what is paternal imprinting?
the gene derived from the dad is inactive
77
if is gene is only expressed if inherited from the father, the gene is ___________________
if is gene is only expressed if inherited from the father, the gene is maternally imprinted
78
what is monoallelic inheritance?
when genes are expressed as if there is only one copy of the gene present even though there are two
79
what does DNA methylation do?
adds a methyl group to the DNA and reduces gene expression
80
ICR stands for...
imprinting coding region
81
what does the ICR site do?
its the binding site for a protein which inhibits imprinting
82
what is the protein which binds to the ICR site?
CTCF
83
what happens when CTFC binds to the ICR site in maternal germ cells?
it blocks igf2 leaving H19 on
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what happens when CTFC binds to the ICR site in paternal germ cells?
CTFC cannot bind to the ICR site in paternal germ cells
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what happens to the ICR site in males?
it becomes methylated, inhibiting CTFC from binding
86
what does the methylation of the ICR site do to the igf2 and H19 sites?
igf2 is on, H19 is off
87
what was the difference between the yellow and brown mice in the example?
In yellow mice, the agouti gene is unmethylated and turn on all the time. In brown mice, the agouti gene in completely methylated and shut down.
88
how did the amount of BPA fed to a pregnant mouse relate to the offspring?
higher increase of yellow mice, DNA methylation was decreased resulting in high health risks.
89
what is heterochromation?
domains of the chromosome that are bundled to be highly condensed. No expression
90
what is euchromatin?
domains of the chromosomes that are less condesned. Expression.
91
what is genetic silencing?
a process which genes are turned off due to a position effect that depends on the neighborhood in which the gene is located
92
what is position effect variegation (PEV)?
when heterochromatin from the centromere region spreads into the euchromatin region and silences the white eyed gene
93
how are calico cats made?
through dosage compensation
94
what is the term used to describe inactive chromosomes?
Barr body
95
what is a Barr body?
inactive chromosomes
96
how is dosage compensation achieved in mammals?
through X-inactivation
97
What can protect bacterial DNA from restriction enzymes?
methylation
98
What are starter cultures of LAB used for?
inoculating milk
99
What do calcium chelators do?
suppress the growth of bacteriophages
100
What are starter cultures sometimes grown in the presence of to prevent the growth of pages?
calcium chelators
101
what are three methods used to prevent the growth of phages?
Phage resistant strains of LAB Phage inhibitory media Recombinant LAB
102
How Is there ampicillin resistance gene removed for the pEM76:cl plasmid?
the B-recombinase gene from PEM68
103
what region is the pEM76:cI plasmid missing and why?
The original site because it is being inserted into a chromosome and we do not want this plasmid to replicate independently.
104
what are the main differences between the PBR322R plasmid and pUC plasmid?
pUC has better ori site pUC has MCS site instead of BamH1 pUC has lac-z gene instead of tetracycline gene
105
what does BIM stand for?
Bacteriophage-insensitive mutants
106
what percentage of our DNA is actually coding?
less than 5%
107
what are transposable elements (TEs)?
sequences of DNA that move from one location in the genome to another
108
who discovered transposons?
Barbara McClintock
109
what were the two factors that McClintock noticed in Indian corn?
the Ds region and Ac region
110
what are autonomous elements?
segments that require no other elements for their mobility
111
what are non-autonomous elements?
segments of DNA that do not encode the functions necessary for their own movement
112
what causes spotted kernels in corn?
autonomous regions, or non-autonomous regions with with an activator
113
what does transposase do?
allows non-autonomous sequences to move. It is the activator.
114
what's a composite transposon?
they contain a variety of genes that reside between two nearly identical IS sequences that are orientated in opposite direction
115
what is an insertion sequence (IS)?
segments of bacteria DNA that can move from one position on a chromosome to a different position on the same chromosome or a different chromosome.
116
what are simple transposons?
regions that contain several genes which are flanked by IR sequences.
117
what are the two mechanisms of transposons?
replicative-makes a copy and stays sending the copy elsewhere
conservative-transposon completely moves from one site to another
118
what are the two classes of transposons in eukaryotes?
tetrotransposons, and DNA transposons
119
what are the three genes of retroviruses?
gag, pol, and env
120
what is hybrid dysgenesis?
refers to the high rate of mutation in germ cells when wild type males are mated with laboratory strain females
121
m strain females + p strain males = ?
sterile flies with frequent mutations
122
p strain females + m strain males = ?
normal flies
123
what is a C-value?
the amount of DNA content in a genome
124
what are the two transposons in humans?
1) long interspread elements (LINES's)-move like a retrotransposon
2) short interspersed elements (SINE's)-non-autonomous LINE's that do not encode a reverse transcriptase
