a. A translation stop codon is added at the 3' end of the pre-mRNA.
c. A poly-A tail (50-250 adenine nucleotides) is added to the 3' end of the pre-mRNA.
d. Coding sequences called exons are spliced out by ribosomes.
Explanation:
In eukaryotes, during protein synthesis, the RNA must exit nucleus through the pores on the nuclear membrane and enter into the cytoplasm to undergo translation.
The exit processes of mRNA are: the 5’ capping, 3’ Poly-A tail, and pre-mRNA splicing.
The 5’capping is the initial step with addition of 7-methylguanosine cap to the 5’ end of the mRNA by phosphate linkage. This process protects the mRNA from degrading and helps to initiate translation processes.
The 3’ Poly-A tail step is the cleaving of pre-mRNA and addition of addition of around 200 A nucleotides or the 3’poly (A) tail to the mRNA by the poly (A) polymerase enzyme protein complex. This prevents pre-mRNA degradation, facilitates movement of mRNA to the cytoplasm, and initiates translation.
Pre-mRNA splicing is done to remove the introns from the mRNA because they are not part of function protein coding. The exons which take part in protein coding sequence are spliced once the introns are excised.
Finally, the resultant mRNA will exit the nucleus and enter the cytoplasm to undergo translation
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A risk behavior is a behavior that carries some form of risk. In the case of teenagers and health risk this can include habits that can be particularly dangerous toward their and other now and future health. protected sex for example is a risky behavior which could cause STD infections.
Being knowledgeable about risk behaviors is a requirement in order to keep teens safe, and develop solutions to such dangers.
I think B makes the most sense
Answer:
On a mid-level shelf in the storage room
