Question

DNA is not present in which one of the following.
A) Mitochondria
B) Chloroplast
C) Bacteriophage
D) Tobacco mosaic virus

Answer 1

Hint: DNA stands for Deoxy ribonucleic acid. It is the molecule which carries genetic information in a living organism.

Complete Answer:
- DNA is the carrier of genetic information. It is transmitted from one generation to another. It is the largest molecule in the living cell. It is the double stranded helical structure. It is composed of a carbon sugar base, a phosphate molecule and nitrogenous base. It is present inside the nucleus of the cell. DNA is responsible for protein synthesis.
- Several organelles in the eukaryotic cells also have DNA. For example- mitochondria and chloroplast that’s why they are called the semi autonomous system. They have single stranded circular DNA. The mitochondrial and chloroplast DNA are inherited from mother to daughter cells without change in genetic composition.
- Bacteriophage is a type of virus that infects bacteria. The bacteriophage has a protein capsid which encloses the genetic material. It may have both DNA and RNA as genetic material.
- TMV or tobacco mosaic virus infects a wide range of plants like tobacco and other pulses. They have RNA as the genetic material.

Thus the correct answer is (D). Tobacco mosaic virus does not have DNA as the genetic material.

Note: DNA is the carrier of hereditary. It is present in the nucleus of the cells. Cell organelles like mitochondria, chloroplast has a single stranded circular DNA which is transmitted to daughter cells.