Question

The list of events below describes intron removal and splicing during pre-mRNA processing. Please select the choice that lists the events in correct sequential order.

1. Attachment of snRNP U1 to the 5′ splice site
2. Transcription of the DNA template into the pre-mRNA molecule
3. Release of lariat structure
4. Splicing together of exons
5. Transesterification reaction at the branch point adenine

a. 1, 2, 3, 4, 5
b. 4, 1, 3, 5, 2
c. 2, 1, 5, 3, 4
d. 3, 5, 1, 2, 4
e. 5, 3, 4, 1, 2

Answer 1

The correct order for intron removal and splicing events in pre-mRNA processing is transcription of the pre-mRNA, attachment of snRNP to the splice site, transesterification at the branch point adenine, release of the lariat structure, and finally splicing together of exons.

Step-by-step explanation:

The question asks for the correct sequence of events for intron removal and splicing during pre-mRNA processing. Let's arrange the given events in the order they occur during splicing:

1. Transcription of the DNA template into the pre-mRNA molecule.
2. Attachment of snRNP U1 to the 5′ splice site.
3. Transesterification reaction at the branch point adenine.
4. Release of lariat structure.
5. Splicing together of exons.

Therefore, the correct sequence of events is option c: 2, 1, 5, 3, 4.