Which of the following does not occur before a eukaryotic mRNA is exported from the nucleus?(a) The ribosome binds to the mRNA.(b) The mRNA is polyadenylated at its 3â² end.(c) 7-methylguanosine is added in a 5â²-to-5â² linkage to the mRNA.(d) RNA polymerase dissociates.

a) The ribosomes binds to the mRNA

Explanation:

The binding of ribosomes to the mRNA happens during the process of translation, which takes place inside the nucleus. DNA is transcribed into messenger RNA (mRNA), and then it is translated into the nucleus, and it is here that mRNA binds to ribosomes and it directs protein synthesis with the help of transfer RNA (tRNA)

a) The ribosome binds to the mRNA.

Explanation:

When RNA transcript made in the nucleus of eukaryotic cells then a process known as pre-mRNA processing started. 7-methylguanosine or 5' cap is added to the start of RNA transcript and polyadenylated or 3' poly-A tail is added to the end of RNA transcript. After that, splicing of RNA transcript occurs in which introns are removed and exons are stuck back together. Then the mRNA matures and exported from the nucleus and reaches in cytoplasm and binds with the ribosome.

So, according to above scenario here the answer is (a).

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure

because of