Controlling Protein Synthesis Flashcards
what is transcription control?
controls which genes are transcribed
the transcription rate
what is post transcriptional control?
-controls modifications to the primary mRNA transcript prior to leaving the nucleus
-addition of the 5’ to 3’ caps
-the removal of introns and the splicing together of exons
what is the post-translational control?
act
a control mechanism that affects the rate at which proteins become active
controls the addition of various chemical groups
controls the time the protein remains functional
what are housekeeping genes?
these are genes always needed in the cell and are thus constantly being transcribed and translated
(the cell is the house and the genes are obtaining its maintenance)
when are genes translated to proteins and why?
it makes more sense to transcribe and translate genes only when they are needed. It’s inefficient for the body the translate genes into proteins at all times because protein synthesis would produce more proteins than the cell needs.
How are transcriptions factors used in eukaryotic cells?
They are used to turn genes on when required
How is transcription and translation regulated in prokaryotic cells?
Prokaryotes used special clusters of genes called operons to regulate transcription and ultimate translation
what is an example of a lac operon?
ecoli bacteria in the gut of mammals can digest lactose. It is economical for bacteria to produce the required enzyme when lactose is availible
which type of cell can use operons to regulate their genes?
only prokaryotes use operons to regulate their genes and products
what is a lactose repressor?
a protein that inhibits transcription of a lactose operon
how does a lactose repressor inhibit a lac operon?
it binds to the operator and partially overlaps with the promoter in such a way to get in RNA polymerase’s way and prevent it from transcribing the operon
how is allolactose created?
when lactose is availible some molecules will be converted into allolactose inside the cell
how does allolactose inhibit the lactose repressor? what does this allow to happen?
it binds to the lactose repressor and makes it change shape so it can no longer bind to DNA
-this allows RNA polymerase to bind to the promoter allowing transcription of the lac operon and production of enzymes needed for the use of lactose
how do researchers control gene expression?
-researchers design and build machines for operons to study the genes they want to investigate. this ultimately gives them the ability to control gene expression
-use of designed antibiotic resistant genes, the designed DNA will carry the desired genes well as an antibiotic resistant gene. Only organisms that express the antibiotic gene will be resistant and grow in the presence of an antibiotic. (like grows with like)
what is translational control?
controls how often and how rapidly mRNA transcripts are translated into proteins
