-. In which phylum does a coelom first appear?

Which of the following environmental conditions would be MOST likely to result in transcription of the lac

Kruka [31]

Answer:

The correct answer is B high levels of lactose and high levels of cyclic AMP.

Explanation:

Lac operon contain 3 regulatory genes and 3 structural genes.In presence of lactose the repressor molecule that is encoded by Lac I gene cannot bound to the operator region.

Bacause the lactose interact with the repressor and change its conformation so that it cannot repress the expression of the structural genes of lac operon.

On the other hand cyclic AMP is a positive regulator of lac operon .The interaction of cyclic AMP with the promoter region of lac operon stimulates the binding of RNA polymerase in the promoter region to boost the expression of structural genes of lac operon such as Lac Z,Lac Y and Lac A.

4 0

3 years ago

In a lab about the activity series, a solution of copper(II)chloride is placed in a test tube with zinc metal. If zinc is higher

Tcecarenko [31]

Answer:

Option D, Zinc is higher on the activity series because there is clear evidence of a reaction.

Explanation:

It is very clear that a metal which is higher in activity will replace a metal having lower activity.

Since, Zinc has higher activity than copper, it is very sure that it in a copper chloride solution it will replace copper and produce zinc chloride solution leaving behind copper as residue.

Residues of copper is a clear evidence of reaction

The chemical equation for this reaction would be -

$CuCl_2 + 2Zn^+ -----> 2ZnCl + Cu^{2+}$