Regulation of gene expression Flashcards
What is the role of the lactose and the lac operon
What is the cAMP
gene expression
Transcribing and translating a gene
Gene regulation
Controlling of and when a gene is expresses, how much RNA / protein products will be produced
Inducer
A substance that causes the expression to begin
Inducible proteins
Starts when the protein is present.
Enhancer
DNA sequences that bind transcription factors to activate
Silencer
binding transcription factor that represses( reduces) transcription
Negative feedback loops vs positive feedback loops
Negative feedback gives a a reduced production of the product
Does prokaryotic have less steps …. WHY
Because mRNA can be rapidly translated as soon as it being transcribed
Negative regulation
On and constitutive blocks transcription
Positive regulation
Off and is inducible. Stimulates transcription
Operon
non transcribed DNA its a line of protomer and operator followed by two or more genes. Stops at the terminator
Advantages and disadvantages of Operons
Advantages- Have a good set of produced genes. Efficient
Disadvantages- Only come in sets so its difficult to just get a copy of 1.
B galactoiclase
is one enzyme that can digest one lactase molecule into two glucoses.
Talk about lactose
It’s not always present and doesn’t always have to produce.
Sigma factors
Bind polymereases and direct them to promoters
What happens if glucose levels are low
Produce cyclic adenosine monophosphate cAMP
Absense of lactose
Binds to a lac operon and prevents RNA synthase from binding to the promoter
B galactosidase is
is a channel protein
How many genes are transcribed per RNA polymerase.
3 genes transcribed each time on the lac
Why is trp operon repressible
to build up extra trp
What kind of feedback loop is trp
hint: on and off
