Question

MRNA decay occurs in these cellular foci - contain DECAPPING ENZYMES, HELICASES, AND EXORIBONUCLEASES. RNA-protein complexes that hold non-translating mRNAs, store until they need to be translated or they're sent for decay. Always there, but the size of these depends on the number of non-translating mRNAs and stress state. mRNAs can also leave this place and resume polysome-associated translation.

A. Ribosomes
B. P-bodies
C. Nucleosomes
D. Proteosomes

Answer 1

The correct answer is B. P-bodies, which are RNA-protein complexes in cells that manage the storage and decay of non-translating mRNAs and can influence protein synthesis through the regulation of mRNA decay.

Step-by-step explanation:

The cellular foci that mRNA decay occurs in and that contain decamping enzymes, helicases, and exoribonucleases are known as P-bodies. P-bodies are dynamic RNA-protein complexes that temporarily store non-translating mRNAs. They can either store these mRNAs until needed for translation or send them for decay. The existence of P-bodies is a constant within the cell, but their size fluctuates depending on the quantity of non-translating mRNAs and the stress state of the cell. Remarkably, mRNAs have the ability to exit P-bodies and resume active translation in association with polysomes.

Mature mRNAs are shielded from degradation by a 5' methylguanosine cap and a poly-A tail. These protective measures, along with splicing to remove introns and connect exons, prepare the mRNA for export from the nucleus to the cytoplasm. Here, the RNA stability determines how long an RNA molecule will reside in the cytoplasm, which, in turn, influences protein synthesis levels. RNA-binding proteins and microRNAs regulate this stability, which can lead to an increased or decreased rate of mRNA decay.