Lec. 29 - Gene Expression

Question 1

Describe how gene expression can be controlled (where, how) for eukaryotes.

Answer 1

Regulation of gene expression for eukaryotes can occur at all stages of the process. Epigenetic, transcriptional, post-transcriptional, translational, and post-translational level.

Question 2

Describe the components of an operon. (POG = promoter, operator genes)

Answer 2

Promoter is where RNA polymerase attaches, Operator “on/off” controls the access of the RNA poly, and Genes has the code for related enzymes in a pathway.

Question 3

Explain the function of a repressor.

Answer 3

Repressors turn off or reduce gene expression.

Question 4

Differentiate between inducible and repressible operons. (Lac, Trp.)

Answer 4

Lac., (lactose) when present, removes the repressor and induces transcription.
Trp., (tryptophan) when present, causes the repressor to stay bound to DNA and repress transcription.

Question 5

Explain how the Lac. and Trp. operons work. (what is the substrate, does this turn the genes on/off, what is produced, etc.)

Answer 5

Lac., (lactose) when present, removes the repressor and induces transcription.
Trp., (tryptophan) when present, causes the repressor to stay bound to DNA and repress transcription.