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Multiple Choice
Which of the following components are removed from pre-mRNA during processing in the nucleus?
A
Exons
B
5' cap
C
Introns
D
Poly-A tail
Verified step by step guidance
1
Understand the structure of pre-mRNA: Pre-mRNA is the initial transcript that is synthesized from DNA during transcription. It contains both exons and introns, as well as a 5' cap and a poly-A tail.
Identify the components of pre-mRNA: Exons are sequences that code for proteins, while introns are non-coding sequences. The 5' cap is a modified guanine nucleotide added to the beginning of the mRNA, and the poly-A tail is a string of adenine nucleotides added to the end.
Learn about mRNA processing: During mRNA processing, introns are removed, and exons are spliced together to form a continuous coding sequence. The 5' cap and poly-A tail are added to protect the mRNA and aid in its export from the nucleus.
Focus on intron removal: Introns are removed from pre-mRNA through a process called splicing. This is carried out by a complex called the spliceosome, which recognizes specific sequences at the intron-exon boundaries.
Recognize the final processed mRNA: After processing, the mature mRNA consists of exons joined together, with a 5' cap and a poly-A tail, ready for translation in the cytoplasm.