An explanation that makes reference to the following:
- post-transcriptional \{modification/change\} (to pre-mRNA) (1)
- (all) introns are removed by \{enzymes / spliceosomes\} (1)
- (some) exons removed (to form each strand) (1)
- some strands have had more exons removed / strand 1 contains \{fewer / 9\} exons / strands 2 and 3 contain \{more / 10\} exons (1)
- all three mRNA strands have {1 / 4 / 5 / 6 / 8 / 9 / 10 \}(exons) (1)
ACCEPT alternative splicing
ACCEPT introns are spliced
IGNORE exons are rearranged ACCEPT active mRNA has few exons than pre-mRNA
ACCEPT correct description of any exon removal differences ACCEPT different strands have different combinations of exons ACCEPT strand 1 has fewer mRNA \{nucleotides / bases\} than strands 2 and 3
ACCEPT all do not have \{7 / 13\} (exons)