Biol 240 - UW - Final Exam Questions and
Correct Answers
Question 1
Endpoint Assay
Correct Answer
Tissue culture infectious dose 50 (TCID50) is the amount of virus needed to induce a
CPE in 50% of cultured cells. CPE is Cytopathic Effect. Lethal dose 50 (LD50) is the
amount of virus needed to kill 50% of test animal subjects. This is not an absolute
number like it is with counting the plaque assay
Question 2
Growth Rate
Correct Answer
Number of generations/unit of time (inverse of the generation time)
Question 3
Disinfectants
Correct Answer
Used on non-living surfaces to kill potentially infectious microbes
Question 4
What binds to the TATA box?
Correct Answer
RNA Polymerase
Page 1 of 110
,Question 5
2D-Page
Correct Answer
Allows separation of proteins on a gel based on isoelectric point (i.e. charge, pH
where the protein has no charge). Mass spectrometry can determine amino acid
sequences of the polypeptides from 2D-PAGE. Comparison of sequence to known
protein sequences can help determine identity
Question 6
What is the Escherichia coli (from your digestive tract) metabolism?
Correct Answer
Chemoorganoheterotroph
Question 7
Temperature
Correct Answer
Can affect macromolecular structure, membrane fluidity, and enzyme function.
Different microbes have different optimal temperature growth ranges
Question 8
Gene Transfer by Hfr
Correct Answer
You start with a F+ cell, then the F plasmid integrates into the chromosome by
homologus recombination to make Hfr. Then the DNA starts to transfer through the
mating bridge into an F- cell. At different periods of time you have different
sequences of DNA transferring (lac operon DNA for eample). So we can map the
genome because we know where each "thing" is on the DNA. We stop the mating
bridge at specific times to see what has made it through to the other cell by seeing
if it can perform the relative function. With this process we can tell if a sequence for
a function is behind or in front of another
Page 2 of 110
,Question 9
·Agrobacterium - Crown-Gall Disease
Correct Answer
The crown gall is where the stem of the plant connects with the roots of the plant.
Causes tumours, parasitism. THIS IS BAD, we don't want this one. Agrobacterium is
the only one that can use opine as a carbon and nitrogen source. It robs the plant
of organic carbon. We can use agrobacterium to introduce new genes into plants
Question 10
All of these would increase the generation time (slower generation) except for?
Correct Answer
Providing oxygen to a facultative anaerobe, this would accelerate division. Remeber
that introducing something into a new medium will have you re-enter the lag phase
which will slow you down
Question 11
Microbial Genetics
Correct Answer
Grew from microbiology 1940s-1950s. Led to molecular biology. Required
development of model systems for genetic investigations (Escherichia coli and
Salmonella typhimurium)
Question 12
Paramecium ingesting algae and using them for photosynthesis.
Correct Answer
It hosts them and allows them to continue with photosynthesis has they are
exposed to the light. They take CÓ and release sugars for paramecium. When the
light is gone and sugar stops being produced, the paramecium will break down the
algae and digest it
Page 3 of 110
, Question 13
Obligate Anaerobes
Correct Answer
Cannot grow when oxygen is present
Question 14
Virus Structure
Correct Answer
Intracellular obligate parasites. Typically between 10 and 100nm. Genome typically a
few thousand to 200,000 nucleotides long (pretty small)
Question 15
Step One - Response to Signal
Correct Answer
Methyl-Accepting Chemotaxis Proteins (MCPs) sense specific attractants/repellants
(initiates signal transduction or not)
Question 16
What is the human metabolism?
Correct Answer
Chemoorganoheterotroph
Question 17
Viral Quantification
Correct Answer
Not easy of straight forward. Usually measured as a titer, or concentration of a virus
preparation. Methods include direct count, hemagglutination assay, plaque assay,
and endpoint assays
Page 4 of 110
Correct Answers
Question 1
Endpoint Assay
Correct Answer
Tissue culture infectious dose 50 (TCID50) is the amount of virus needed to induce a
CPE in 50% of cultured cells. CPE is Cytopathic Effect. Lethal dose 50 (LD50) is the
amount of virus needed to kill 50% of test animal subjects. This is not an absolute
number like it is with counting the plaque assay
Question 2
Growth Rate
Correct Answer
Number of generations/unit of time (inverse of the generation time)
Question 3
Disinfectants
Correct Answer
Used on non-living surfaces to kill potentially infectious microbes
Question 4
What binds to the TATA box?
Correct Answer
RNA Polymerase
Page 1 of 110
,Question 5
2D-Page
Correct Answer
Allows separation of proteins on a gel based on isoelectric point (i.e. charge, pH
where the protein has no charge). Mass spectrometry can determine amino acid
sequences of the polypeptides from 2D-PAGE. Comparison of sequence to known
protein sequences can help determine identity
Question 6
What is the Escherichia coli (from your digestive tract) metabolism?
Correct Answer
Chemoorganoheterotroph
Question 7
Temperature
Correct Answer
Can affect macromolecular structure, membrane fluidity, and enzyme function.
Different microbes have different optimal temperature growth ranges
Question 8
Gene Transfer by Hfr
Correct Answer
You start with a F+ cell, then the F plasmid integrates into the chromosome by
homologus recombination to make Hfr. Then the DNA starts to transfer through the
mating bridge into an F- cell. At different periods of time you have different
sequences of DNA transferring (lac operon DNA for eample). So we can map the
genome because we know where each "thing" is on the DNA. We stop the mating
bridge at specific times to see what has made it through to the other cell by seeing
if it can perform the relative function. With this process we can tell if a sequence for
a function is behind or in front of another
Page 2 of 110
,Question 9
·Agrobacterium - Crown-Gall Disease
Correct Answer
The crown gall is where the stem of the plant connects with the roots of the plant.
Causes tumours, parasitism. THIS IS BAD, we don't want this one. Agrobacterium is
the only one that can use opine as a carbon and nitrogen source. It robs the plant
of organic carbon. We can use agrobacterium to introduce new genes into plants
Question 10
All of these would increase the generation time (slower generation) except for?
Correct Answer
Providing oxygen to a facultative anaerobe, this would accelerate division. Remeber
that introducing something into a new medium will have you re-enter the lag phase
which will slow you down
Question 11
Microbial Genetics
Correct Answer
Grew from microbiology 1940s-1950s. Led to molecular biology. Required
development of model systems for genetic investigations (Escherichia coli and
Salmonella typhimurium)
Question 12
Paramecium ingesting algae and using them for photosynthesis.
Correct Answer
It hosts them and allows them to continue with photosynthesis has they are
exposed to the light. They take CÓ and release sugars for paramecium. When the
light is gone and sugar stops being produced, the paramecium will break down the
algae and digest it
Page 3 of 110
, Question 13
Obligate Anaerobes
Correct Answer
Cannot grow when oxygen is present
Question 14
Virus Structure
Correct Answer
Intracellular obligate parasites. Typically between 10 and 100nm. Genome typically a
few thousand to 200,000 nucleotides long (pretty small)
Question 15
Step One - Response to Signal
Correct Answer
Methyl-Accepting Chemotaxis Proteins (MCPs) sense specific attractants/repellants
(initiates signal transduction or not)
Question 16
What is the human metabolism?
Correct Answer
Chemoorganoheterotroph
Question 17
Viral Quantification
Correct Answer
Not easy of straight forward. Usually measured as a titer, or concentration of a virus
preparation. Methods include direct count, hemagglutination assay, plaque assay,
and endpoint assays
Page 4 of 110
