Prokaryotic Gene Regulation via Operons quiz #2 Flashcards
Prokaryotic Gene Regulation via Operons quiz #2
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Which gene transfer method involves the uptake of free DNA by competent bacterial cells?
The gene transfer method that involves the uptake of free DNA by competent bacterial cells is transformation. Which of the following are the three main methods of gene transfer in bacteria? A) Transformation, B) Transduction, C) Conjugation, D) Replication
The three main methods of gene transfer in bacteria are A) Transformation, B) Transduction, and C) Conjugation. What is the purpose of operons in protein synthesis?
The purpose of operons in protein synthesis is to regulate the expression of related genes in prokaryotes, allowing for coordinated control of gene expression in response to environmental changes. Which of the following is constitutively (always) expressed in a prokaryotic cell? A) Structural genes, B) Regulatory genes, C) Housekeeping genes, D) Inducible genes
C) Housekeeping genes are constitutively expressed in a prokaryotic cell. What is the advantage of operon organization in bacteria?
The advantage of operon organization in bacteria is that it allows for the coordinated regulation of genes that are involved in the same metabolic pathway, enabling efficient and rapid responses to environmental changes. The operon model for the control of gene expression was discovered by which of the following? A) Watson and Crick, B) Jacob and Monod, C) Mendel, D) Darwin
The operon model for the control of gene expression was discovered by B) Jacob and Monod. How do bacterial regulatory proteins mediate negative control of transcription?
Bacterial regulatory proteins mediate negative control of transcription by binding to the operator region of an operon and blocking RNA polymerase from initiating transcription. Which of the following is an example of positive control in operons? A) Lac operon activation by CAP, B) Trp operon repression, C) Lac operon repression by LacI, D) Trp operon activation
A) Lac operon activation by CAP is an example of positive control in operons. What is the consensus sequence for the Pribnow box from these sequences?
The consensus sequence for the Pribnow box, also known as the -10 region in prokaryotic promoters, is typically TATAAT. Which of the following RNA processing mechanisms occur in prokaryotes? A) Capping, B) Polyadenylation, C) Splicing, D) None of the above
D) None of the above. Prokaryotes generally do not undergo RNA processing mechanisms such as capping, polyadenylation, or splicing. Control of gene expression in prokaryotic cells occurs at which level(s)? A) Transcriptional, B) Post-transcriptional, C) Translational, D) All of the above
A) Transcriptional. Control of gene expression in prokaryotic cells primarily occurs at the transcriptional level. What controls transcription in prokaryotes?
Transcription in prokaryotes is controlled by regulatory proteins that bind to the operator region of operons, influencing RNA polymerase's ability to initiate transcription. Which is a correct statement about rho-independent termination?
Rho-independent termination involves the formation of a hairpin loop in the RNA transcript followed by a series of uracil residues, causing the RNA polymerase to dissociate from the DNA. Which of the following must occur in order for a repressible operon to be transcribed? A) Repressor must be inactive, B) Corepressor must bind to repressor, C) Inducer must bind to repressor, D) Activator must bind to operator
A) Repressor must be inactive. For a repressible operon to be transcribed, the repressor must be inactive, allowing RNA polymerase to bind to the promoter and initiate transcription. What is an operon in prokaryotic gene regulation, and what are its main components?
An operon is a group of related prokaryotic genes controlled by a single promoter. Its main components are the promoter (where RNA polymerase binds), the operator (a DNA sequence where regulatory proteins bind), and the structural genes. The operator regulates transcription by interacting with regulatory proteins such as repressors or activators. Describe the mechanism of repressible operons and the function of a corepressor.
Repressible operons are usually on, allowing gene expression. However, when a corepressor molecule is present, it binds to the inactive repressor protein, activating it. The active repressor then binds to the operator, blocking transcription and turning the operon off. What is the role of the operator in an operon, and how do regulatory proteins affect transcription?
The operator is a DNA sequence within the operon where regulatory proteins bind. Repressors binding to the operator block RNA polymerase and inhibit transcription, while activators can promote RNA polymerase binding and stimulate transcription.
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