You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium. Next you isolate a mutation, designated MelB–, which gives uninducible melibiase activity. Mapping experiments show that MelB– is linked to Mel1. Using an F' factor that carries the chromosomal region surrounding Mel1, you perform the following genetic tests:

 

Describe the proposal for the type of regulatory functions affected by the MelB– mutation.

#Question id: 4542

#Unit 3. Fundamental Processes

Repression of the GAL1 gene in yeast by Mig1, in the presence of glucose follows those steps;

I- Deacetylation of local nucleosomes

II-Recruiting the Tup1 repressing complex

III- Mig1 represses expression of GAL1

IV- Mig1 binds a site between the UASG and the GAL1 promoter

#Question id: 4543

#Unit 3. Fundamental Processes

Control of the activator NtrC- In that case, the signal (low ammonia levels) induces a kinase that phosphorylates NtrC. This is type of

A. Indirect signaling

B. Direct signaling

C. Is an example of a signal transduction pathway

#Question id: 4544

#Unit 3. Fundamental Processes

How is the binding of ligand to the extracellular domain communicated to the intracellular domain?

#Question id: 4545

#Unit 3. Fundamental Processes

Through which signal transduction pathway- controls the activators such as Jun, one of the activators that works at the interferon-beta enhancer

#Question id: 4546

#Unit 3. Fundamental Processes

In eukaryotes, transcriptional regulators are not typically controlled at the level of DNA binding (although there are exceptions). Regulators are instead usually controlled in one of the following two basic ways.

I. Unmasking an Activating Region

II. Transport into and out of the Nucleus

III. Mediated through proteolysis of an inhibitor or tethering region or by allosteric changes.

IV. Also is itself (or recruits) a deacetylase,

#Question id: 4547

#Unit 3. Fundamental Processes

Transcription always done in