Answer:
D.) repressor DNA-binding site mutation
Explanation:
lacl prevents the repressor polypeptide is a mutant that prevent operon from binding lactose, and thus will bind to the operator and be non-inducible.. This mutant will represses the lac operon whether lactose is present or not and the lac operon will not be expressed. It is also called“super-supperesor".
The lacI locus – One type of mutant allele of lacI (callled I-) prevents the production of a repressor polypeptide or produces a polypeptide that will not allow to bind to the operator sequence.
This is also a constitutive expresser of the lac operon because absence of repressor binding permits transcription.
Answer:
A. The tails do not interact with the DNA
Explanation:
The acetylation refers to the transfer of the acetyl group from Acetyl-CoA to the N-terminal of the histone protein.
Lysine residues (positively charged amino acid) are present at the end of the N-terminal of the histone protein which is neutralized by the acetyl group.
This loses the compaction between the positively charged histone and the negatively charged DNA and the DNA becomes more relaxed. This relaxed state allows the transcription factors to easily bind the DNA and therefore the DNA becomes transcriptionally active.
Thus, Option-A is correct
The cell divides and grows in the organ of origin, causing a localized tumor. Cancer cells then spread to adjacent tissues or regional lymph node drainage areas, and then advance to distant organs or structures, creating metastatic tumors.
The heart is a muscle, therefore, if the cardiac muscles stopped contracting, the result would be the ceasing of heart function. That would lead to death, as blood wouldn't be pumped throughout the body. Homeostasis would therefore be interrupted.
The cycle that is described in the problem is called the water cycle. in this cycle, the water from a lake is evaporated through the heat of the sun and the water is accumulated in the clouds. When the clouds are saturated, then water condenses and precipitates to fall as rain.
