- Following statements were made about mitochondria:
(A) The D loop of the mitochondrial genome is required for replication, but not for the
regulation of transcription.
(B) The L strand of mitochondrial genome possesses more cytosine.
(C) In plants, most mitochondrial tRNAs are encoded by the nuclear genome and then imported into the mitochondrion.
(D) Cycloheximide inhibits protein synthesis by mitochondrial ribosomes, but does not affect eukaryotic cytosolic ribosomes.
(E) Some organisms have been found to carry linear mitochondrial DNA.
Which one of the following options represents a combination of the correct statements?
(1) A, B, C (2) B, D, E
(3) A, C, D (4) B, C, E
Analysis of Each Statement
(A) The D loop of the mitochondrial genome is required for replication, but not for the regulation of transcription.
-
Incorrect. The mitochondrial D-loop region is involved in both replication and transcription regulation. It contains promoters for transcription initiation and plays a role in controlling mtDNA replication.
(B) The L strand of mitochondrial genome possesses more cytosine.
-
Correct. The light (L) strand is relatively rich in cytosine compared to the heavy (H) strand, which is guanine-rich [general mitochondrial genome knowledge].
(C) In plants, most mitochondrial tRNAs are encoded by the nuclear genome and then imported into the mitochondrion.
-
Correct. Unlike animals, many plant mitochondrial tRNAs are encoded in the nuclear genome and imported into mitochondria to supplement mitochondrial translation [general mitochondrial biology].
(D) Cycloheximide inhibits protein synthesis by mitochondrial ribosomes, but does not affect eukaryotic cytosolic ribosomes.
-
Incorrect. Cycloheximide inhibits eukaryotic cytosolic ribosomes but does not inhibit mitochondrial ribosomes, which resemble bacterial ribosomes [general knowledge of cycloheximide].
(E) Some organisms have been found to carry linear mitochondrial DNA.
-
Correct. While most mitochondrial genomes are circular, some species (including certain fungi and protists) possess linear mitochondrial DNA [general knowledge].
Correct Combination of Statements
(4) B, C, E
Summary Table
| Statement | Correctness | Explanation |
|---|---|---|
| A | Incorrect | D-loop involved in both replication and transcription regulation |
| B | Correct | L strand is cytosine-rich |
| C | Correct | Plant mitochondria import many tRNAs encoded by nuclear genes |
| D | Incorrect | Cycloheximide inhibits cytosolic, not mitochondrial, protein synthesis |
| E | Correct | Some organisms have linear mitochondrial DNA |
Keywords
mitochondrial D-loop, mitochondrial L strand, cytosine-rich strand, plant mitochondrial tRNAs, tRNA import, cycloheximide inhibition, mitochondrial ribosomes, linear mitochondrial DNA, mitochondrial genome structure
Conclusion
The correct statements about mitochondria are that the L strand is rich in cytosine, many plant mitochondrial tRNAs are nuclear-encoded and imported, and some organisms possess linear mitochondrial DNA. The D-loop region participates in both replication and transcription regulation, and cycloheximide inhibits cytosolic ribosomes but not mitochondrial ribosomes. Therefore, the correct combination is B, C, and E.
Final answer:
(4) B, C, E
25 Comments
Soniya Shekhawat
July 29, 2025Yes 4 option BCE is correct l loop is rich in cytosine and some organisms have a linear mitochondrial replication, plant mitochondrial import many trna encoded by nuclear gene
Alec Joseph
July 31, 2025Correct ans is 4 because mitochondrial d loop region is involved in both replication and transcription and L strand is rich in cytosine, many plant mitochondrial tRNAs are nuclear encoded and some organisms possess linear mitochondrial DNA.
Anisha jakhar
July 29, 2025The correct option is 4, BCE as the l strand is C rich, in plants most of the mit. tRNA is encoded by nuclear genome and some organisms carry linear mit. DNA.
Savita Garwa
July 29, 2025Yes sir 4 option BCE is correct answer
Shivani Panwar
July 29, 2025Ans is 4
Deepika sheoran
July 30, 2025Yes option 4(BCE) is right.The l Loop has a lot of cytosine, some organisms use linear mitochondrial replication, and plant mitochondria take trna from genesin the nucleus..
Deepika sheoran
July 30, 2025Yes option 4(BCE) is right.The l Loop has a lot of cytosine, some organisms use linear mitochondrial replication, and plant mitochondria take trna from genes in the nucleus..
Kajal
July 30, 2025Option 4 is right
Because l loop is c rich and some organisms have linear mitochondrial dna replication and plants mitochondria take trna from genes in the nucleus
anurag giri
July 30, 2025Ans 4 L strand is rich in cytosine in plant mitochondrial tRNAs are nuclear-encoded and imported into mitochondria and some organisms have linear mitochondrial DNA
Vijay kumar Meena
July 30, 2025Done ✔️
Mansukh Kapoor
July 30, 2025The correct answer is option 4th because the mtDNA have cytosine rich L strand and the tRNAs are nuclear encoded and transferred into mitochondria and some mtDNA can be in linear form also.
Pratibha Sethiya
July 30, 2025Correct option is option (4)
L strand is rich in cytosine
In plant trna is transported to the mitochondria
Mit.DNA are in linear form in some organisms
Niti tanwar
July 30, 2025Answer is 4
Mahima sharma
July 30, 2025Explain pls
Komal Pareek
July 30, 20254 is correct
Anjali
July 31, 2025Yes sir option 4 (bce) is correct answer.
Dharmpal Swami
August 1, 2025B C E are write statement
SHOBHA SHARMA
August 1, 2025Answar B , C and E
L strand is cytosine rich
plant mt. import many t-rna encoded by nuclear gene
some organism have linear mt. dna
Varsha tatla
August 2, 2025Option a,d is incorrect bcz mitochondrial d loop involve in regulation of replication n transcription both
In Option d cyclohexamide inhibits by cytoclsolic eukaryotic ribosomes
Varsha tatla
August 2, 2025Option a,d is incorrect bcz mitochondrial d loop involve in regulation of replication n transcription both
In Option d cyclohexamide inhibited by cytoclsolic eukaryotic ribosomes
Manisha choudhary
August 3, 2025Mitochondria ki L strand cytocine rich and H strand guanine rich hoti h , D loop replication and transcription regulations dono k liye important h kyoki isme promoter hota h jo transcription initiation krwata h
Cycloheximide eukaryotic cytosolic ribosomes ko inhibit krti h mitochondrial ko nhi kyoki y bacteria k genmone s resemble krta h
Kuch organism (certain protista and fungi )m mitochondrial genome linear hota h
Anita choudhary
August 22, 2025Option BCE is correct because l strand is cytosolic rich.
Some organism have mirtrochondrial dna .
Plant mitochondria import many tRNAs encoded by nuclear genes.
Aafreen Khan
August 23, 20254) B, C, E
Mitochondrial DNA strands are in Heavy and Light. The L strand is typically richer in cytosine.
Plant mitochondria is a significant number of tRNAs encoded by the nuclear genome
Most mitochondrial genome are circular but some species like fungi have linear mitochondrial genome
vishal saini
September 18, 2025correct answer 4th
Deepika Sheoran
November 7, 2025Option 4 th is correct