MCB 3023 Exam 1 questions with
verified answers latest update
In Type III secretion, which protein seems to mimic flagellin?
A. the protein being exported
B. the cytoplasmic component of the Type III secretion complex
C. the transmembrane component of the Type III secretion complex
D. the syringe-like component of the Type III secretion complex
E .none is a comparable protein - correct answer A
Which is the correct distinction between a heterotroph and an autotroph?
A. An autotroph utilizes carbon dioxide as an energy source and a heterotroph utilizes organic
compounds as an energy source.
B. An autotroph utilizes carbon dioxide as a carbon source and a heterotroph utilizes organic
compounds as a carbon source.
C. An autotroph utilizes organic compounds as an energy source and a heterotroph utilizes carbon
dioxide as an energy source.
D. An autotroph utilizes complex organic compounds as a carbon source and a heterotroph utilizes
simple organic compounds as a carbon source.
E. An autotroph utilizes organic compounds as a carbon source and a heterotroph uses carbon
dioxide as a carbon source. - correct answer B
,Which best describes a photoautotroph?
A. Utilizes sunlight for energy and organic molecules as a carbon source
B. Utilizes sunlight as an energy source to fix carbon dioxide
C. Emits light from the fixation of carbon dioxide
D. Emits light from the breakdown of organic carbon
E. Uses organic compounds as a source of carbon and energy. - correct answer B
Given the size of a typical ribosome, how many would you expect to find inside a typical bacterium of
1-5 µm size?
A. 1000 - 5000 ribosomes
B. 100-200 ribosomes
C. 20 ribosomes
D. single ribosome
E. 100,000 - 1,000,000 ribosomes - correct answer A
Which of these constitute valid reasons why actin polymer formation by Shigella should be
considered as a strong virulence factor?
A. Actin can propel bacterial cells from one side of a host cell to another
B. Actin polymers allow bacteria to invade an epithelial sheet without immune cell exposure
,C. Actin polymer formation adheres bacterial cells to host cells
D. Actin polymers trigger the expression of host defenses
E. None is a valid reason to consider actin polymer formation as a virulence - correct answer B
Phospholipid structure in archaeal cells suggests relatedness to:
A. Bacteria
B. Prokaryotes
C. Eukaryotes
D. All other life forms
E. No other life forms; their structure is unique - correct answer E
Which of these gene expression errors will result in heritable genetic change?
A. DNA polymerase error introducing an incorrect base
B. RNA polymerase error creating a mutated mRNA
C. RNA polymerase creating a mutated rRNA
D. RNA polymerase creating a mutated tRNA
E. All will lead to heritable changes - correct answer A
, When would you speculate that the extinction of most eukaryal life forms without mitochondria
would have begun?
A. 3.5 billion ybp
B. 3 billion ybp
C. 2 billion ybp
D. 1 billion ybp
E. 500 million ybp - correct answer C
During ammonification, microorganisms convert:
A. Amino acids to ammonia
B. Ammonia to dinitrogen gas
C. Ammonia to nitrates
D. Dinitrogen gas to ammonia
E. None is a correct choice - correct answer A
Which of these gene products appears to confer a survival advantage on bacteria living in a
competitive environment?
A. TonB dependent receptors
B. TonB
verified answers latest update
In Type III secretion, which protein seems to mimic flagellin?
A. the protein being exported
B. the cytoplasmic component of the Type III secretion complex
C. the transmembrane component of the Type III secretion complex
D. the syringe-like component of the Type III secretion complex
E .none is a comparable protein - correct answer A
Which is the correct distinction between a heterotroph and an autotroph?
A. An autotroph utilizes carbon dioxide as an energy source and a heterotroph utilizes organic
compounds as an energy source.
B. An autotroph utilizes carbon dioxide as a carbon source and a heterotroph utilizes organic
compounds as a carbon source.
C. An autotroph utilizes organic compounds as an energy source and a heterotroph utilizes carbon
dioxide as an energy source.
D. An autotroph utilizes complex organic compounds as a carbon source and a heterotroph utilizes
simple organic compounds as a carbon source.
E. An autotroph utilizes organic compounds as a carbon source and a heterotroph uses carbon
dioxide as a carbon source. - correct answer B
,Which best describes a photoautotroph?
A. Utilizes sunlight for energy and organic molecules as a carbon source
B. Utilizes sunlight as an energy source to fix carbon dioxide
C. Emits light from the fixation of carbon dioxide
D. Emits light from the breakdown of organic carbon
E. Uses organic compounds as a source of carbon and energy. - correct answer B
Given the size of a typical ribosome, how many would you expect to find inside a typical bacterium of
1-5 µm size?
A. 1000 - 5000 ribosomes
B. 100-200 ribosomes
C. 20 ribosomes
D. single ribosome
E. 100,000 - 1,000,000 ribosomes - correct answer A
Which of these constitute valid reasons why actin polymer formation by Shigella should be
considered as a strong virulence factor?
A. Actin can propel bacterial cells from one side of a host cell to another
B. Actin polymers allow bacteria to invade an epithelial sheet without immune cell exposure
,C. Actin polymer formation adheres bacterial cells to host cells
D. Actin polymers trigger the expression of host defenses
E. None is a valid reason to consider actin polymer formation as a virulence - correct answer B
Phospholipid structure in archaeal cells suggests relatedness to:
A. Bacteria
B. Prokaryotes
C. Eukaryotes
D. All other life forms
E. No other life forms; their structure is unique - correct answer E
Which of these gene expression errors will result in heritable genetic change?
A. DNA polymerase error introducing an incorrect base
B. RNA polymerase error creating a mutated mRNA
C. RNA polymerase creating a mutated rRNA
D. RNA polymerase creating a mutated tRNA
E. All will lead to heritable changes - correct answer A
, When would you speculate that the extinction of most eukaryal life forms without mitochondria
would have begun?
A. 3.5 billion ybp
B. 3 billion ybp
C. 2 billion ybp
D. 1 billion ybp
E. 500 million ybp - correct answer C
During ammonification, microorganisms convert:
A. Amino acids to ammonia
B. Ammonia to dinitrogen gas
C. Ammonia to nitrates
D. Dinitrogen gas to ammonia
E. None is a correct choice - correct answer A
Which of these gene products appears to confer a survival advantage on bacteria living in a
competitive environment?
A. TonB dependent receptors
B. TonB
