Prokaryotes and eukaryotes Gene_Regulation_Flashcards
What is gene regulation?
The process of controlling which genes are expressed and to what extent, dictating cell fate and function.
What are operons?
Clusters of genes in prokaryotes that are regulated together for a specific function.
At what level is prokaryotic gene regulation primarily controlled?
The transcriptional level.
What are repressors?
Proteins that bind to operator regions and inhibit transcription.
What are activators?
Proteins that bind to promoter sites and enhance transcription.
What are inducers?
Small molecules that can activate or repress transcription based on cellular needs.
What is the lac operon?
A system in E. coli regulating genes for lactose metabolism.
Name the structural components of the lac operon.
lacI gene, CAP binding site, promoter, operator, and structural genes (lacZ, lacY, lacA).
What happens to the lac operon in the presence of lactose?
Lactose is converted to allolactose, which binds to the repressor, allowing transcription.
How does low glucose affect the lac operon?
Low glucose increases cAMP, which binds to CAP, enhancing RNA polymerase binding and transcription.
What is the trp operon?
A repressible system regulating tryptophan biosynthesis.
How is the trp operon regulated when tryptophan levels are high?
Tryptophan binds to the trp repressor, which blocks transcription by binding to the operator.
Why is eukaryotic gene regulation more complex than in prokaryotes?
Due to a larger genome, separation of transcription and translation, and multiple regulation levels.
List the levels of eukaryotic gene regulation.
Chromatin accessibility, transcription, RNA processing, RNA stability, translation, and protein activity.
How does chromatin structure affect gene regulation?
Chromatin modifications influence gene accessibility for transcription.
What role do transcription factors play?
They bind to specific DNA sequences to regulate transcription initiation.
What processes are involved in RNA processing?
Splicing, capping, and poly-A tail addition.
How is RNA stability regulated?
By controlling the lifespan of mRNA molecules in the cytoplasm.
How is protein activity regulated post-translationally?
Through modifications like phosphorylation and ubiquitination.
What are cis-acting regulatory sequences?
DNA sequences like promoters, enhancers, and silencers that influence transcription of nearby genes.
What are transcription factors?
Proteins that regulate transcription by binding to DNA regulatory sequences.
What is alternative splicing?
The process of producing different mRNA isoforms from a single pre-mRNA by including or excluding exons.
What is the role of microRNAs (miRNAs)?
They target mRNAs for degradation or inhibit their translation.
What is mRNA editing?
The alteration of nucleotide sequences in mRNA molecules, affecting protein sequences.
What is phosphorylation?
Addition of phosphate groups to proteins to alter their activity, localization, or interactions.
What is ubiquitination?
Attachment of ubiquitin to proteins, marking them for degradation by the proteasome.
