Question

ctivity: protein synthesis -- rna processing
rt a - rna processing
g the correct labels under the diagrams to identify the events of rna processing.
extra adenine nucleotides are added to the end of the rna strand, forming a tail. the completed messenger rna (mrna) leaves the nucleus. segments of the rna that do code for the protein are reconnected. segments of the rna strand that do not actually code for the protein are removed. a modified guanine nucleotide is added to the beginning of the rna strand as a cap.
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Explanation:

Step1: Recall RNA processing steps

RNA processing has 3 main steps: capping (adding 5' cap), polyadenylation (adding poly - A tail), and splicing (removing introns and joining exons), then mRNA exits nucleus.

Step2: Analyze each diagram

• Diagram 1 (1st): Looks like adding a cap (modified guanine at start) → "A modified guanine nucleotide is added to the beginning of the RNA strand as a cap."
• Diagram 2 (2nd): Segments (introns) being removed → "Segments of the RNA strand that do not actually code for the protein are removed."
• Diagram 3 (3rd): After splicing, exons reconnected → "Segments of the RNA that do code for the protein are reconnected."
• Diagram 4 (4th): Adding adenine nucleotides (poly - A tail) → "Extra adenine nucleotides are added to the end of the RNA strand, forming a tail."
• Diagram 5 (5th): mRNA leaving nucleus → "The completed messenger RNA (mRNA) leaves the nucleus."

Answer:

1. A modified guanine nucleotide is added to the beginning of the RNA strand as a cap.
2. Segments of the RNA strand that do not actually code for the protein are removed.
3. Segments of the RNA that do code for the protein are reconnected.
4. Extra adenine nucleotides are added to the end of the RNA strand, forming a tail.
5. The completed messenger RNA (mRNA) leaves the nucleus.