Question: Describe a type of catabolite repression?

Answer: When glucose is present, the lac operon is inhibited.

Question: One reason that regulation of gene expression is important is that it saves energy and materials from being used when they are not needed. At which point would regulation be most efficient in conserving energy and materials if the product of a gene is not needed?

Answer: transcriptional regulation (regulation of whether transcription occurs

Question: Cells can regulate their metabolism by regulating enzyme activity or by regulating synthesis (i.e., by regulating whether they produce the enzyme for the reaction). Which of the following examples would be best when an enzyme needs to be available very rapidly?

Answer: An enzyme is activated by the binding of a molecule to its allosteric site.

Question: How can DNA binding proteins (DBP) regulate transcription?

Answer: DNA binding proteins can activate transcription.

DNA-binding proteins can catalyze transcription.

DNA-binding proteins can block transcription.

Question: What would be the most likely effect of a mutation in the operator of a lac operon?

Answer: The genes would be constitutively expressed

Question: Regulation by induction and repression are called negative control because __________.

Answer: Transcription proceeds in the absence of the repressor protein.

Question: Define what an effector is in genetic regulation.

Answer: Effectors are small molecules that induce or repress transcription of a specific gene.

Question: What is the inducer molecule in the lac operon?

Answer: Allolactose

Question: With which genetic region does the repressor protein interact?

Answer: The operator region

Question: When the cell is not in the presence of lactose,

Answer: the repressor proteins bind to the operator.