Answer to Question #58961 in Cell Biology for tracy guido

Question

After an mRNA strand has been transcribed from DNA, it must be processed before translation can take place. Which of the following statements are true about the RNA editing process?
Additional amino acids are added before translation occurs,
noncoding segments are removed and exons are joined together,
a cap is added to one end of the mRNA,
editing occurs in the cytosol as the new mRNA strand leaves the nucleus. (more than one answer)


Which statement describes an operon?
Heritable changes in gene expression that occur without altering the DNA sequence,
mRNA modifications, such as the addition of a 5\'-cap and 3\' poly-A tail and the removal of introns,
a gene cluster controlled by a single promoter that transcribes to a single mRNA strand,
the processing of exons in mRNA that results in a single gene coding for multiple proteins,
protein modifications, such as the addition of a functional group, or alternate folding of the protein

Answer 1

Question 1. Correct answers - noncoding segments are removed and exons are joined together,
a cap is added to one end of the mRNA. These two events occur during RNA maturation in nucleus. Amino acids cannot be added to mRNA.

Question 2. Correct answer - a gene cluster controlled by a single promoter that transcribes to a single mRNA strand. Operon consists of promoter, operator and structural genes. One mRNA is produced from it and it encodes for several proteins.