Gene regulation Flashcards
Differences in cell regulation between bacteria and eukaryotic cells
Transcriptional-level control is the most common way for a prokaryotic cell to regulate gene expression, while in eukaryotic cells it occurs at all levels.
Operon
In bacteria. Is a gene complex consisting of a group of structural genes with related functions plus the closely linked DNA sequences responsible for controlling them.
Promoter
A part of a operon where RNA polymerasa first binds to DNA before transcription begins.
Operator
A part of an operon that serves as the regulatory switch for transcriptional-level control of the operon. The binding of a repressor protein to the operator sequence prevents transcription.
Inducible operon
It is an operon normally turned off and needs to be activated.
Repressible operon
It is an operon normally turned on and needs to be inactivated.
Constitutive genes (in bacteria)
Are neither inducible nor repressible, they are active all the times.
Posttranscriptional control in bacteria
A translational control regulates the rato of translation of a mRNA.
Feedback inhibition of key enzimes in some metabolic pathways.
Eukaryotic genes
Not organized into operons. Their regulation occurs at level of rtanscription, mRNA processing, translation and modifications of the protein product.
TATA box (Eukaryotic)
The promoter contains it and it has a regulatory function and facilitates expression of the gene.
Enhancers and silencers (Eukaryotic)
Located thousands of bases away from the promoter, they increase or decrease the rate of transcription.
Transcription factors
DNA-binding proteins that control gene expression.
Heterochromatin
Densely packed regions of chromosomes containing inactive genes.
Euchromatin
Loosely packed chromatin structure of active genes.
Epigenetic inheritance
It is an important mechanism of gene regulation that involves changes in how a gene is expressed. They provide a mechanism for epigenetic inheritance.
