THE MOLECULAR BASIS OF INHERITANCE
DNA MAKES RNA MAKES PROTEIN
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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5’ cap and 3’ poly A tail added, in nucleus
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3’ cap and 5’ poly A tail added, in cytoplasm
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introns cut out and exons reattached, nucleus
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introns cut out and exons reattached, cytoplasm
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Detailed explanation-1: -A 7-methylguanosine cap is added to the 5′ end of the pre-mRNA while elongation is still in progress. The 5′ cap protects the nascent mRNA from degradation and assists in ribosome binding during translation. A poly (A) tail is added to the 3′ end of the pre-mRNA once elongation is complete.
Detailed explanation-2: -Ribosomal RNA synthesis and processing occurs in a special structure within the nucleus called the nucleolus . The mature rRNAs bind to ribosomal proteins within the nucleolus and the assembled ribosomes are then transported to the cytoplasm to carry out protein synthesis.
Detailed explanation-3: -Both ends of a pre-mRNA are modified by the addition of chemical groups. The group at the beginning (5’ end) is called a cap, while the group at the end (3’ end) is called a tail.
Detailed explanation-4: -The processing of the 3’ end adds a poly-A tail to the RNA molecule. First, the 3’ end of the transcript is cleaved to free a 3’ hydroxyl. Then an enzyme called poly-A polymerase adds a chain of adenine nucleotides to the RNA.
Detailed explanation-5: -The 5’ cap protests the newly-synthesized mRNA from degradation. It also assists in ribosome binding to help initiating translation. 3’ poly-A tail protects mRNA from degradation, aids in exporting the mature mRNA to the cytoplasm, and is also involved in binding proteins to initiate translation.