A scientist isolates mRNA from the cytoplasm of some mouse cells. She separately isolates the DNA from mouse cells and heats the DNA to make it single-standard. She mixes the single-stranded DNA with the mRNA and allow hybrid (DNA-mRNA) double-stranded molecules to form. She observes long loops of single-stranded nucleic acid in the hybrid molecules. Are the single-stranded regions in the DNA strand or in the mRNA strand? What part of the gene do these loops represent? Would your expect to find these same loop structures if the scientist used RNA and DNA from bacteria rather than from mice?

Answer is explained below.

Explanation:

A. The  observed  single  stranded  regions  are  found  in  the  mRNA.

B. The  loops  represent  introns  (Non-coding  portions  of  the  mRNAin primary  transcript ).  The  intron  sequences  are  removed  to  form  a mature mRNA  by  splicing.

C. If  the  scientist  use  RNA  and  DNA  from  bacteria,  loops  cannot be seen. Because introns are produced in only eukaryotes but not in prokaryotes.

single-stranded regions are found in the messenger RNA structure.

As for the looped structure those are called INTRONES.

And regarding the comparison between a eukaryotic cell (animal) and a prokaryotic cell (Bacteria), the prokaryotic cells do not present INTRONS.

Explanation:

Introns are structures that are then isolated to form mature mRNAs through the splicing process.

the sphincter muscles at the end of the digestive tract is the anus.