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?
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.
