Microbio 303 Exam test assessment
with answers graded A+
A bacterium comes into contact with a negative chemical stimulus. In which way will its flagella
rotate to productively move the bacterium? - ANS✅✅Counter clockwise, this is the fastest most
productive form of movement
All of the following are true about evolutionary relatedness of organisms EXCEPT... -
ANS✅✅Cyanobacteria are related to mitochondrion because of their Gram-negative cell wall
You create a pool of mutants such that each one changes one base pair in the coding region of in the
gene glutamate synthase. About 33% of the changes do not cause a detectable change in the activity
of the enzyme. This is because - ANS✅✅The genetic code is redundant and many times a change
in the 3rd base of the codon still codes for the same amino acid.
Which of the following characteristics are similar across prions and viruses? - ANS✅✅Both are
disease-causing agents
What is the correct order of the steps involved in transcription- - ANS✅✅Recognition, Formation
of open complex, Elongation, Termination
A microbe exhibiting chemotaxis should do which of the following when a positive stimulus is
introduced into the environment? - ANS✅✅Move toward the positive stimulus in a series of runs
of random direction, runs toward the positive stimulus last longer than runs away from the stimulus
Major cellular differences between Archaea and Bacteria are - ANS✅✅Promoter start sites
(pribnow box in Bacteria vs. TATA box in Archaea
What is the main difference between DNA and RNA according to their pentose sugar structure? -
ANS✅✅DNA does not have an OH attached to its 2' position
In the process of a virus infecting a cell, the virus binds to the cell, invaginates, forms an endosome,
and the cell absorbs nutrients from the endosome. What kind of cell is this and which step comes
next in the viral infection pathway? - ANS✅✅Eukaryotic; Gene Expression
Process being described is the endocytic route of a virus entering a cell, entry process is only found
in eukaryotic cells
, Which of the following microbes were most essential to the evolution of eukaryotes and
subsequently most organisms? - ANS✅✅Cyanobacteria
What discovery allowed us to finally characterize microbes, despite them being discovered by Thonis
Philipszoon in the 17th century? - ANS✅✅Agar
Which of the following statement(s) is/are true regarding the structures of DNA and RNA. I. DNA has
a narrower/deeper major groove that makes it more rigid for protein access, because it lacks 2'OH II.
In eukaryotes, both 5' and 3' end of a mRNA imparts stability to the mRNA III. Archaea and bacteria
both have 16S small subunit rRNA which is different from eukarya IV. tRNA must be charged with the
correct amino acid for translation. The first charged amino acid in bacteria is methionine -
ANS✅✅II and III
Which bacteriophage(s) contain double-stranded DNA and can go thought a lytic cycle? - ANS✅✅λ
and T4
What is a MAJOR difference between prokaryotes and eukaryotes in the process of translation? -
ANS✅✅Shine-Dalgarno sequence
A microbe using chemotaxis changes its direction of motion by - ANS✅✅Rotating flagella clockwise
to enter tumble, then proceed in a random direction by rotating counterclockwise
In chemotaxis, microbes either run in a straight line or tumble. Tumbling causes the microbe to point
in a random direction. Microbes move in a desired direction by lengthening runs in the desired
direction and shortening runs away from the desired direction. There is no reverse gear.
Which of the following best summarizes the evidence that mitochondria and chloroplasts evolved
from bacteria and cyanobacteria respectively? - ANS✅✅Analysis of the 16S rRNA of the ribosomes
in chloroplasts and mitochondria reveals similar sequences to those found in the 16S rRNA of
bacteria and cyanobacteria. - correct - Your answer
If the CII protein of the &lamda; bacteriophage had a frameshift mutation, the λ virus would not
longer be able to - ANS✅✅Enter the lysogenic phase
You discovered a strange microorganism. You want to first examine the motile microorganism in its
natural state and then to determine the structure of the protein that forms the pili. What kinds of
microscopes you should use? - ANS✅✅Phase Contrast Microscope and X-Ray Crystallography
with answers graded A+
A bacterium comes into contact with a negative chemical stimulus. In which way will its flagella
rotate to productively move the bacterium? - ANS✅✅Counter clockwise, this is the fastest most
productive form of movement
All of the following are true about evolutionary relatedness of organisms EXCEPT... -
ANS✅✅Cyanobacteria are related to mitochondrion because of their Gram-negative cell wall
You create a pool of mutants such that each one changes one base pair in the coding region of in the
gene glutamate synthase. About 33% of the changes do not cause a detectable change in the activity
of the enzyme. This is because - ANS✅✅The genetic code is redundant and many times a change
in the 3rd base of the codon still codes for the same amino acid.
Which of the following characteristics are similar across prions and viruses? - ANS✅✅Both are
disease-causing agents
What is the correct order of the steps involved in transcription- - ANS✅✅Recognition, Formation
of open complex, Elongation, Termination
A microbe exhibiting chemotaxis should do which of the following when a positive stimulus is
introduced into the environment? - ANS✅✅Move toward the positive stimulus in a series of runs
of random direction, runs toward the positive stimulus last longer than runs away from the stimulus
Major cellular differences between Archaea and Bacteria are - ANS✅✅Promoter start sites
(pribnow box in Bacteria vs. TATA box in Archaea
What is the main difference between DNA and RNA according to their pentose sugar structure? -
ANS✅✅DNA does not have an OH attached to its 2' position
In the process of a virus infecting a cell, the virus binds to the cell, invaginates, forms an endosome,
and the cell absorbs nutrients from the endosome. What kind of cell is this and which step comes
next in the viral infection pathway? - ANS✅✅Eukaryotic; Gene Expression
Process being described is the endocytic route of a virus entering a cell, entry process is only found
in eukaryotic cells
, Which of the following microbes were most essential to the evolution of eukaryotes and
subsequently most organisms? - ANS✅✅Cyanobacteria
What discovery allowed us to finally characterize microbes, despite them being discovered by Thonis
Philipszoon in the 17th century? - ANS✅✅Agar
Which of the following statement(s) is/are true regarding the structures of DNA and RNA. I. DNA has
a narrower/deeper major groove that makes it more rigid for protein access, because it lacks 2'OH II.
In eukaryotes, both 5' and 3' end of a mRNA imparts stability to the mRNA III. Archaea and bacteria
both have 16S small subunit rRNA which is different from eukarya IV. tRNA must be charged with the
correct amino acid for translation. The first charged amino acid in bacteria is methionine -
ANS✅✅II and III
Which bacteriophage(s) contain double-stranded DNA and can go thought a lytic cycle? - ANS✅✅λ
and T4
What is a MAJOR difference between prokaryotes and eukaryotes in the process of translation? -
ANS✅✅Shine-Dalgarno sequence
A microbe using chemotaxis changes its direction of motion by - ANS✅✅Rotating flagella clockwise
to enter tumble, then proceed in a random direction by rotating counterclockwise
In chemotaxis, microbes either run in a straight line or tumble. Tumbling causes the microbe to point
in a random direction. Microbes move in a desired direction by lengthening runs in the desired
direction and shortening runs away from the desired direction. There is no reverse gear.
Which of the following best summarizes the evidence that mitochondria and chloroplasts evolved
from bacteria and cyanobacteria respectively? - ANS✅✅Analysis of the 16S rRNA of the ribosomes
in chloroplasts and mitochondria reveals similar sequences to those found in the 16S rRNA of
bacteria and cyanobacteria. - correct - Your answer
If the CII protein of the &lamda; bacteriophage had a frameshift mutation, the λ virus would not
longer be able to - ANS✅✅Enter the lysogenic phase
You discovered a strange microorganism. You want to first examine the motile microorganism in its
natural state and then to determine the structure of the protein that forms the pili. What kinds of
microscopes you should use? - ANS✅✅Phase Contrast Microscope and X-Ray Crystallography
