Correct option is D
Explanation-
Statement A - The D loop of the mitochondrial genome is required for replication, but not for the regulation of transcription - Incorrect
The D-loop does play a role in both replication and transcription. It contains the origin of replication and the promoters for transcription. So, saying it is not involved in transcription regulation is false.
Statement B -The L strand of mitochondrial genome possesses more cytosine - Correct
The L (Light) strand is cytosine-rich, hence lighter than the G-rich H (Heavy) strand. This statement is true.
Statement C - In plants, most mitochondrial tRNAs are encoded by the nuclear genome and then imported into the mitochondrion - Correct
In plant mitochondria, many tRNA genes are missing. So, the nucleus encodes these tRNAs, and they are imported into mitochondria. This is true.
Statement D - Cycloheximide inhibits protein synthesis by mitochondrial ribosomes, but does not affect eukaryotic cytosolic ribosomes - Incorrect
This is reversed. Cycloheximide inhibits cytosolic (80S) ribosomes. It does not inhibit mitochondrial (prokaryotic-like, 70S) ribosomes. So this is false.
Statement E - Some organisms have been found to carry linear mitochondrial DNA - Correct
Yes, linear mitochondrial DNA has been observed in some fungi, protozoa, and yeasts. This statement is true.
Thus, the correct combination is: B, C, E
Hence, correct option is d - B, C, E
