Unit 5 Quiz 3

1. Compare and contrast genome structure in prokaryotes and eukaryotes. With regard to arrangement of genes, size of genes, coding vs. non coding DNA

Prokaryotes: Singular circular chromosome, Does not contain a large amount of non-coding DNA

Eukaryotes: Multiple long strands, Contain quite a bit of non-coding DNA

• At what points during the production of proteins can gene expression be controlled (i.e. stopped/started/modified)?

Eukaryotes: 

• Transcription: when are they are transcribed and which ones 

• Post transcriptional: Doesn't splice, doesn’t get a cap or tail, maybe it gets degraded

• Translation: Can stop initiation 

• Post-Translation: if it doesn’t need the protein it can degrade it, if it does then it activates it.

Prokaryotes: Operons control protein production during the transcription phase. Different operons will 

3. Why is it important for organisms to control whether their genes are active or inactive?

   In order to not use valuable resources and waste time doing so, being able to control when genes are active or not ensures that proteins are being created that actually need to be

4. What is an operon? 

   As they way genes can be turned on and off in prokaryotic cells, they allow for the management of transcriptions, and therefore management of the production of proteins

5. Describe the features common to all operons. What is the function of each of these features?

Containing an operator, repressor protein corepressor/coreducer, promoter, and regulator and structural genes.

The Operator: The Operator is where the repressor protein will bind when active which will inactivate transcription.

Repressor: The repressor when active and binded to the operator will inactivate the transcription process The coInducer will bind to an active repressor protein and cause it to be inactive allowing transcription to occur

Compressor: The Corepressor will bind to an inactive repressor protein in order for the protein to bind to the operator site and inactivate the transcription process

6. Describe the way that bacteria control production of tryptophan (trp operon). Why is the trp operon considered a repressible operon? How is this an example of feedback inhibition?Bacterial control production of tryptophan acts exactly like as an example of feedback inhibition because when enough tryptophan is produced on of the molecules will go back and as an corepressor to deactivate transcription

   
   

7. What is the relationship between glucose and lactose? What is the function of B-galactosidase? Lactose can be broken into allolactose and then into glucose as a source of energy for bacteria.

8. Describe how the lac operon works to control breakdown of lactose.Why is this operon considered inducible?