Unit 3-Molecular Genetics Lesson 6 1.0-2.0 Flashcards
What does lactose do for prokaryotes?
It is a potential source of energy for prokaryotes.
Lac Operon is what?
A cluster of three genes that code for the proteins involved in lactose metabolism.
What are the 3 components of Lac Operon?
Promoter Site
Operator
Coding Regions
What is the function of the Promoter Site?
where DNA transcription begins
What is the function of the Operator?
The sequence of the bases that controls transcription
What is the function of the Coding Regions?
Code for the various enzymes that metabolize lactose.
What is located upstream from the Lac Operon? Which does what?
A gene that codes for a repressor protein.
What does the Lac Operon do?
takes cues from the environment and regulates the production of the lactose metabolizing proteins
With regards to the Lac Operon, what is the repressor protein called?
lacI or lac repressor
What occurs in the absence of lactose?
the lac repressor is active and binds to the operator,
What does the Lac Repressor keep RNA Polymerase from doing?
binding to the promoter and stops the lactose metabolizing enzymes from continually being synthesized
What does the Lac Repressor do in the presence of lactose? (x2)
some of it binds to a site on the lac repressor, rendering it inactive,
this makes it unable to bind to the operator and block transcription
What does Trp Operon do?
Same thing as Lac Operon - except codes for the protein Tryptophan
What is tryptophan important for?
Building proteins
What does trp operon have that is the same as lac operon?
The same structure
What is the repressor protein called for Trp Operon?
trp repressor
What occurs in the absence of tryptophan? (x3)
the repressor protein is in the inactive state and does not bind to the operator,
RNA polymerase is able to bind to the promoter region and the transcription of the genes to produce tryptophan can proceed
What occurs in the presence of tryptophan?
the repressor protein is activated and is able to bind to the operator, and stop transcription
What is the unchecked growth and indefinite lifespan of cancer cells the result of?
Changes in gene expression/regulation
What is the effect that the usual mechanisms and signals that allows healthy cells to express their genes properly on cancerous cells?
Have little to no effect
What do healthy cells contain?
A set of genes that code for various proteins that stimulate cell growth.
What do cancerous cells contain/are?
Contain mutations/become mutated.
What are mutated cells/genes called?
Oncogenes
What do Oncogenes cause?
The constant cell division.
