Question

Check all of the statements that are true about micrornas (mirnas)

O The human genome contains genes that produce miRNAs.
O miRNAs are only synthetic; they are produced when scientists introduce transgenes into organisms. These so- called RNA-interference transgenes have promoters at each end of a CDNA, and thus produce double-stranded RNA, which is then processed into miRNAs.
O The targets of miRNAs are mRNAs of a specific genes.
O A single miRNA targets all mRNAs.
O Ribosomes are the targets of miRNAs; miRNAs bind to ribosomes to prevent translation.
O miRNAs prevent translation of their target genes by binding to their mRNAs, which can result in mRNA degradation by the RISC complex.
O miRNAs bind to their target RNAs by complementary base pairing and hide the ribosome binding site, thus preventing translation
O Some mRNAs produce both proteins and miRNAs; other mRNAs produce miRNAs only.

Answer 1

MicroRNAs (miRNAs) do not come from mRNA but are transcribed from miRNA genes within DNA. They regulate gene expression by targeting mRNAs for degradation or repressing their translation. mRNA, rRNA, and tRNA all have separate, distinct functions within the process of protein synthesis.

Step-by-step explanation:

When considering the various types of RNA and their functions, microRNAs (miRNAs) play a critical role in the regulation of gene expression. Unlike messenger RNA (mRNA), which carries the code from DNA for protein synthesis, miRNAs are involved in silencing mRNA by targeting them for degradation or inhibiting their translation. It's important to note that mRNAs do not produce miRNAs; rather, miRNAs are transcribed from specific miRNA genes within the DNA.

Ribosomal RNA (rRNA) is a structural component of ribosomes and is crucial for protein synthesis, while transfer RNA (tRNA) carries amino acids to the ribosome to be added to the developing protein strand. Each of these molecules has distinct roles, and none of the mRNAs produce both proteins and miRNAs. Some sequences in DNA are indeed transcribed into miRNAs, which then regulate the expression of mRNA strands, influencing the protein output of the cell.