list when, during the flow of genetic information, bacterial cells can regulate
ID: 42193 • Letter: L
Question
list when, during the flow of genetic information, bacterial cells can regulate gene expression compare and contrast housekeeping, constitutive, inducible, and repressible genes summarize how negative transcriptional control and positive transcriptional control can be used to regulate both inducible and repressible genes compare and contrast regulation of transcription elongation by attenuation and riboswitches explain why the coupling of transcription and translation in bacterial cells is important to the regulatory mechanisms they use distinguish translational riboswitches from transcriptional riboswitches discuss regulation of translation by antisense RNAs list the nucleotides that are used by bacteria as second messengers explain how alternate sigma factors can be used to initiate transcription of distinct sets of operons summarize how CAP, cAMP, and the lac repressor work together to cause diauxic growth as well as other outcomes related to regulation of the lactose operon Define quorum sensing What is the regulatory mechanisms used by Bacillus subtilis to control endospore formationExplanation / Answer
The flow of genetic information is from DNA to RNA (transcription) to protein (translation). In bacteria transcription and translation occurs simultaneously and the genes are expressed only when they are required by the cells.
The housekeeping genes are those genes that are required for the maintainnance of basic cellular functions. These are constitutive genes. The constitutive genes are those that are always expressed in a cell. An inducible operon is a cluster of genes that undergo transcription when an inducer binds to the operator of the operon and the genes are expressed.
A repressible operon is a cluster of genes whose transcription is turned off when the repressor molecule binds to the operator and the genes are not exressed.
An inducer when initiates the transcription when the cell requires the genes and the repressor turns off the genes when the cell does not require them. This is the example of positive control of gene expression. Catabolite repression or an intermediate product represses the gene expression is tye negative control of gene expression.
An inducer or repressor act as riboswithches and initiate or terminate the transcription depending on the cellular requirement of gene products. Attenuation is premature stopping of transcription process. The segment of DNA acts as an attenuator that either stops or proceeds transcription depending on the cellular requirement.
The coupling of transcription and translation in prokaryotic cells like bacteria is key regulatory point because, depending on the cellular needs either a gene product is transcribed and translated or stopped.
The transciptional and translational riboswithches are the transciptional factors (initiation, elongation and termination) and translational factors (initiation, elongation and termination) whose binding or dissociation starts, continues or stops the transcription and translational processes respectively.
In bacteria single stranded complementary RNA is synthesized from mRNA participates in the gene expression. Sometimes this RNA interferes with transcription and translation processes to stop them.
The CAP and cAMP are the cyclic nucleotides used as second messengers in bacteria.
Several promoters (sigma factors ) are required for transcription of specific operons.
When the CAP binds the lac repressor is turned off because of the presence of Glucose in the medium. When all the glucose is used up, the cell synthesizes the cAMP and the lac operon is turned on to utilise the lactose present in the medium.
quorum sensing is the coordinated gene expression in prokaryotic cells like bacteria depending on the cellular density. The chemical stimulations triggers the gene expression in all cells simultaneously.
When the cellular density is high and the bacterial cells are under the starvation conditions the transcriptional factors stimulate the cells express the sporulation genes and the cells undergo sporulation. Several genes of B. subtilis are directly or indirectly will be under the control of spo0A transcriptional factor and the cells undergo sporulation.
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