operon

in the lac operon model the genes within the operon will be expressed if:

lactose is present in the cell

what would happen if the positions of the promoter and operator were reversed

the repressor will not prevent the RNA polymerase from transcribing genes

what is the operator

-located between the promoter and structural genes -when repressor protein is bound to operator, it prevents RNA polymerase from transcribing the structural genes

The lac operon structural genes only become expressed if:

lactose binds to the repressor

what is the advantage to having one promoter and one operator associated with three structural genes that produce lactose metabolizing enzymes?

it will save energy and time with one switch because we can transcribe genes at one time

what is the role of operons in a prokaryote gene expression aka protein synthesis ?

it accounts for the regulation of gene activity in response to the needs of the cells

what is the role of the promoter

a DNA sequence that binds RNA polymerase to begin the process of transcription of the DNA strand to make mRNA

What is an operon?

a unit made up of linked genes that code for proteins needed to do a specific task

repressive negative control is when the gene is transcribed by the - of a specific molecule

absence

what is the role of the regulator gene

contains the genetic code for the repressor protein

what would happen if there was a mutation in one of the structural genes

enzymes will not be created. There will be no transcription of the structural gene and mRNA will not be produced. mRNa will not carry information correctly. Gene switches will not control multiple genes

what is the role of structural genes

has the code to build the enzymes needed to break down lactose

the "on/off" switch for an operon is called the

operator

inducible negative control is when the gene is transcribed by the - of a specific molecule

presence

operons are found in the cells of which of the following types of organisms?

prokaryotes (bacteria)

what is the name of the stretch of DNA where RNA polymerase binds

promoter

a protein that binds to the operator and blocks the RNA polymerase

repressor

what would happen if there was a mutation in the promoter

the DNA sequence will not bind to RNA polymerase. So, transcription would never start. Therefore, there will be no production of the enzymes

how can a person's muscle have the same exact DNA sequences as their nerve cells even though they look and perform completely differently

the proteins expressed in each cell are different

what would happen if there was a mutation in the operator

the represessorprotein will never bind to the operator. So, it won't prevent RNA polymerase from transcribing structural genes