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MCB4403 Ch. 10 Homework Questions
with Detailed Verified Answers
Question: In E. coli, eight enzymatic steps are involved in the biosynthesis of
arginine from glutamate. The synthesis of the required enzymes is subject to
control by the ArgD protein, which, on its own, binds weakly to a regulatory
sequence just downstream of the promoter regions for these genes. Upon the
addition of excess arginine to the growth medium, the respective mRNA
molecules are no longer produced. What is the likely role of arginine in the
control of these genes?
Answer: corepressor
Question:
Genes for which of the following functions would be constitutively expressed
in a bacterial cell such as E. coli?
Answer: DNA replication
Question:
Which of the following are features of operons? Select all that apply.
Answer: operator, promoter, protein-coding genes
Question:
What is the role of the first structural gene (lacZ) in the lac operon? Select all
that apply.
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Answer: it isomerizes lactose into allolactose, it breaks down lactose into
glucose and galactose
Question:
Increased synthesis of _____ is a direct result of decreasing glucose levels.
Answer: cAMP
Question:
Which of the following elements must be present for attenuation of the trp
operon to occur? Select all that apply.
Answer: charged tRNA Trp, RNA polymerase, ribosomes
Question:
When intracellular levels of tryptophan are low, the _________ stem loop
forms, which results in ___________ of transcription.
Answer: 2:3 / progression
Question:
What are the primary mechanisms by which E. coli regulates the amount and
activity of its heat-shock sigma H? Select all that apply.
Answer: translational control, proteolysis by chaperones
Question:
MCB4403 Ch. 10 Homework Questions
with Detailed Verified Answers
Question: In E. coli, eight enzymatic steps are involved in the biosynthesis of
arginine from glutamate. The synthesis of the required enzymes is subject to
control by the ArgD protein, which, on its own, binds weakly to a regulatory
sequence just downstream of the promoter regions for these genes. Upon the
addition of excess arginine to the growth medium, the respective mRNA
molecules are no longer produced. What is the likely role of arginine in the
control of these genes?
Answer: corepressor
Question:
Genes for which of the following functions would be constitutively expressed
in a bacterial cell such as E. coli?
Answer: DNA replication
Question:
Which of the following are features of operons? Select all that apply.
Answer: operator, promoter, protein-coding genes
Question:
What is the role of the first structural gene (lacZ) in the lac operon? Select all
that apply.
, Page | 2
Answer: it isomerizes lactose into allolactose, it breaks down lactose into
glucose and galactose
Question:
Increased synthesis of _____ is a direct result of decreasing glucose levels.
Answer: cAMP
Question:
Which of the following elements must be present for attenuation of the trp
operon to occur? Select all that apply.
Answer: charged tRNA Trp, RNA polymerase, ribosomes
Question:
When intracellular levels of tryptophan are low, the _________ stem loop
forms, which results in ___________ of transcription.
Answer: 2:3 / progression
Question:
What are the primary mechanisms by which E. coli regulates the amount and
activity of its heat-shock sigma H? Select all that apply.
Answer: translational control, proteolysis by chaperones
Question:
