What is hnRNA?Explain the changes the hnRNA undergoes during its processing to form mRNA?

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hnRNA (also known as Pre-mRNA) is a primary transcript formed after transcription of DNA.

hnRNA has both introns and exons. To form mature RNA (mRNA) hnRNA go through a process known as splicing to remove unwanted intron from it and also 5' and 3' ends of hnRNA are modified. 5' end is modified by the addition of cap of 7-methylguanosine and 3' end is modified by the addition of poly A tail.