Answer:
A
Explanation:
A.reserching the amount of sunscreen to apply to the skin
Scientific equipment has helped athletes gain a competitive edge in the Olympic winter games by improving their routine work-outs, and helps them achieve the level of athletic ability that they needed to.
The sympathetic nervous system can accelerate heart rate. Decreases the movement of the large intestine, constricts blood vessels. Can cause piloerection aka goosebumps and perspiration also known as sweating a lot of times.
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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