Question

Which of the following is not true regarding mRNA splicing and mRNA export from the nucleus?

A. Spliced mRNA are exported with the assistance of the Ran pathway.
B. An mRNA that undergo splicing is exported more rapidly than an identical mRNA which has the intron genetically removed.
C. All of the given answers are true.
D.Exon junction complexes assist in mRNA export.
the answer for this is not C.

The CRISPR/Cas system used in labs to modify many different organisms includes (select all that apply):
A. DNA from a bacteria virus
B. an sgRNA molecule
C. The nuclease domain of Cas9
D. The polymerase domain of Cas9

Answer for this is not all of the above.

Answer 1

1. Correct ans is A

Basically, Ran pathway is stimulated by Ran GAP (GTPase activating protein). Ran independent pathway is required for the export of spliced mRNA. Ran GAP is involved in export of tRNA nad U1 snRNA and its activity is increased by RanBP1.

Splicing is required and mRNA that undergoes splicing are more rapidly exported than identical mRNA which has been intron genetically removed.

Nucleotides upstream of mRNA that are a part of exon-exon junctions are basically required for assisting in mRNA export.

2. Correct ans is a,b and c

CRISPR are derived from DNA from bacteria and hence this system includes DNA from bacteria virus. It specifically contains DNA from bacteriophage i.e a virus that infects the bacteria.

sgRNA is single guide RNA. Cas-9 forms a complex with sgRNA where Cas-9 is anchored with target ssDNA. This gives aconformation in alpha helical lobe which forms a tight inteaction between sgRNA and ssDNA complex.

The nuclease domain of cas-9 is involved in this system. This cas-9 nuclease forms a complex with gRNA (synthetic guide RNA). This basically helps to cut the specific genomes at specific location and removal and existing genes and replaced with the new ones. It basically open the strands of the desired specific DNA that is targeted.