Question

Which of the following statements about group I and group II introns is NOT true?

1) Both group I and II introns form elaborate and characteristic secondary structures with loops.
2) The splicing mechanism of group II introns is similar to that of spliceosome mediated nuclear pre-mRNA splicing.
3) The length of group I and group II introns is much longer than the exons within the structures.
4) Group I and group II introns are exclusively found in mitochondrial and chloroplast encoded genes.
5) Both Group I and group II introns are both found in bacterial genes.

Answer 1

Group I and group II introns are not exclusively found in mitochondrial and chloroplast encoded genes.

Step-by-step explanation:

The statement that is NOT true about group I and group II introns is number 4) Group I and group II introns are exclusively found in mitochondrial and chloroplast encoded genes.

Group I and Group II introns are actually found in several different types of genes. Group I introns are found in mRNA and tRNA genes in bacteria, mitochondrial genes, chloroplast genes, and occasionally in bacteriophage genes. Group II introns are found in chloroplast and mitochondrial rRNA, mRNA, and tRNA genes, as well as some bacterial mRNAs. Therefore, statement 4) is not true.