Question

Q. Which of the following bodies possess extranuclear genetic material?

Select the correct answer from the code given below:

• A. 1, 2 and 5 only
• B. 3 and 4 only
• C. 1, 2, 3 and 4 only
• D. 1, 2, 3, 4 and 5

Answer 1

The correct option is C 1, 2, 3 and 4 only

Explanation:

• Extranuclear inheritance (cytoplasmic inheritance) is the transmission of genes that occur outside the nucleus. It occurs in most eukaryotes and is common in cytoplasmic organelles such as mitochondria and chloroplasts or from cellular parasites like viruses or bacteria. There is no concept of the presence of the true nucleus as an organelle in the case of bacteria and viruses and their naked genetic material is present in the cytoplasm itself. Moreover, the bacterial cells also possess plasmids as extra genetic material which helps in various processes from reproduction to resistance against harmful agents.
• In eukaryotes, the extranuclear DNA is found in both Mitochondria and chloroplast. While mitochondria are present in both plant and animal cells, the chloroplast is exclusively present in plants. Mitochondria have a small circular extranuclear DNA, and they are also known as semi-autonomous organelles. Mitochondrial DNA is inherited from the mother to offspring.
• The nucleolus is part of the nucleus itself and is called the brain of the nucleus. It is the site of transcription and processing of rRNA and assembly of pre-ribosomal subunits. Therefore, it consists of ribosomal DNA, RNA, and ribosomal proteins, including RNA polymerases, imported from the cytosol.