Ch. 10 Regulating the Flow of Information Flashcards
(38 cards)
Why is gene expression regulated?
Because gene products of a cell are not always needed, or are not always needed in the same amounts.
Where does gene expression regulation occur and what does it cause?
Regulation of gene expression can occur at seven points of the gene expression process. Any of these points will affect the amount of active protein present in a cell or organelle?
What are the seven points where gene expression can be regulated?
Transcription initiation, postranscriptional processing, RNA stability, translation, protein modification, protein transport, and protein degredation.
What are activator and repressors?
They bind gene regulatory sequences and affect transcription rate.
What is DNA looping and what does it do?
DNA looping is when you loop the DNA. It can occur at a distance or locally and will induce or repress expression depending on the gene.
Where is DNA looping more common?
It is more common in eukaryotes.
What are coactivators and corepressors?
They can mediate the interaction between regulatory proteins and RNA pol.
What do insulator sequences do?
Accidental expression of other genes in an area is prevented by insulator sequences that prevent cross-signaling.
What is signal integration?
Signal integration occurs when activators and repressors control a single gene.
What does signal integration allow for?
It allows for control of expression in response to more than one environmental signal (e.g. lac operon).
What do feedback loops do?
Feedback loops control regulatory protein activity.
How are regulatory proteins controlled as it pertains to feedback loops? Compound control?
Regulatory proteins can be activated or inactivated by the presence of a compound. The concentration of that compound depends on the processes related to the gene being regulated?
What can effectors/SEMs be?
NOT proteins. They can be carbohydrates, amino acids, lipids, etc.
Where are operons common?
It is common in prokaryotes and very rare in eukaryotes.
What does transcription of an operon produce?
Transcription of an operon produces polycistronic RNA containing the coding regions for multiple proteins.
What does the grouping of genes into operons allow for?
It allows for the regulation of proteins that function together.
Do eukaryotes group genes together if they don’t use operons?
While eukaryotes rarely have operons, they have other mechanisms to regulate expression of proteins that function together.
What does the use of more regulators in eukaryotic genes allow?
It allows for integration of multiple signals and is related to cells having greater complexity and larger genomes.
How are protein binding sites distributed in eukaryotic genes?
More complex organisms have more protein binding sites in their genes, but the sites are used in multiple genes.
What is combinatorial control?
In eukaryotic genes; precise control of gene expression due to the combination of protein binding.
What is a recognition helix and what does it do?
A recognition helix of a protein interacts with the DNA helix and is often found as a dimer.
What is the typical structure of DNA binding sites?
DNA binding sites are often short inverted repeats.
What is a common structural theme of prokaryotic regulatory proteins?
helix-turn-helix motif
What is a common structural theme of multicellular organism regulatory proteins?
homeodomain similar to h-t-h motifs
