BILD 1 Chapter Notes - Chapter 15: Noncoding Dna, Transgenerational Epigenetic Inheritance, Rna Splicing

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greyserval924

9 Mar 2018

School

UCSD

Department

Biology/Lower Division

Course

BILD 1

Professor

Rachel Dutton

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Document Summary

Bacteria tune their metabolism to changing environments by regulation of tryptophan. Operon model: basic mechanism that controls gene expression in bacteria. Coordinately controlled genes have a single on-off switch that can control the whole cluster of functionally related genes. Operator: the on-off switch that controls the access of rna polymerase to the genes they control; within the promoter. Operon: the entire stretch of dna required for enzyme production for the tryptophan pathway. Repressor: binds to the operator and blocks the attachment of rna polymerase to the promoter, preventing transcription of the genes; specific. Regulatory gene: located by operon and has own promoter. Corepressor: a small molecule that cooperates with a repressor protein to switch an operon off. Repressible operon: transcription is usually on but can be repressed when a specific small molecule binds allosterically to a regulatory protein. Inducible operon: transcription is usually off but can be stimulated when a specific small molecule interacts with a regulatory protein.

Related Questions

Complete the following to describe the role that an operon plays in the synthesis of enzymes in prokaryotes.

An operon consists of an operator gene, a promoter gene, and the structural genes. When a repressor is bound to the operator, RNA polymerase cannot bind to the _________operatorpromoterstructural genes to start transcription of the _________operatorpromoterstructural genes. When a(n) _________helicaseinducerrepressorribosome is present, it binds to and inactivates the _________helicaseinducerrepressorribosomeRNA polymerase. This inactive _________helicaseinducerrepressorribosomeRNA polymerase can no longer bind to the operator. As a result, _________helicaseinducerrepressorribosomeRNA polymerase can bind to the promoter, leading to eventual transcription of the _________operatorpromoterstructural genes that encode the enzymes to be synthesized.

-operator

-promoter

-structural genes

carminechinchilla384

Fill in the blank:

promotor, induction, presence, will not, will, operon, repressor, repression, overabundance, operator, control region,

1. If the repressor is bound to the operator, then RNA polymerase______ transcribe the structural genes.

2. The ________ controls whether RNA polymerase can advance along the DNA strand or not.

3. The _______ operates differently depending on whether the operon is inducible or repressible.

4. An _________ controls the expression of functionally related genes and consists of a control region and structural genes.

5. ______ decreases expression of the structural genes. This typically occurs in response to an _____ of a substrate.

6. The _____ contains a promoter and an operator.

7. If the repressor is not bound to the operator, then RNA polymerase _____ transcribe the structural genes.

8. ______ increases expression of the structural genes. This typically occurs in response to the _______ of a substrate.

9. The ______ is the region of DNA where RNA polymerase initially binds.

In the following points, I have summarized Lac operon in Ecoli. I need to check if this is on the right track? and where does 'cleavage of disaccharides' fit into this picture?

Lactose is a disaccharide and the bacteria need specific genes to manage catabolism

1) The lacl promotor gene synthesis the repressor protein which binds to the operator gene stopping the RNA polymerase from coding the lac operon genes

2)But when lactose is present, it needs the specific genes to catabolise lactose

3) So, When allolactose (a derivative of lactose)is present, it binds to the repressor protein, the repressor releases from the operator gene

4) This allows the RNA polymerase can attach to the DNA control region

5) And drive down the operon for transcription and induction of the enzyme lacZ(beta-galactosidase) lacY and lacA which breaks lactose down into glucose and galactose

6) When the lactose is all gone, the repressor returns to the operator in a feedback loop system

BILD 1 Chapter Notes - Chapter 15: Noncoding Dna, Transgenerational Epigenetic Inheritance, Rna Splicing

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