NCERT Class XII Chemistry
Chapter - Biomolecules
Questions with Solutions
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Question : 24
Total: 33
Write the important structural and functional differences between DNA and RNA.
Solution:
Difference between DNA and RNA.
| DNA | RNA | |
|---|---|---|
| 1. | It usually occurs inside nucleus and some cell organelles. | Very little RNA occurs inside nucleus. Most of it is found in the cytoplasm. |
| 2. | DNA is the genetic material. | RNA is not the genetic material except in certain viruses, e.g., TMV, Reovirus. |
| 3. | It is double stranded with a-helix structure in which two strands are coiled spirally. | RNA is single stranded with the exception of some viruses (e.g., double stranded in Reovirus). |
| 4. | DNA shows regular helical coiling. | There is no regular coiling except in parts of tRNA. |
| 5. | DNA is of only two types, nuclear and extra-nuclear. | There are at least three types of RNA-mRNA, rRNA and tRNA. |
| 6. | It contains deoxyribose sugar. | It contains ribose sugar. |
| 7. | Nitrogen base thymine occurs in DNA along with three other -adenine, cytosine and guanine. | Thymine is replaced by uracil in RNA. The other three are adenine, cytosine and guanine. |
| 8. | It has a unique property of replication. | It does not replicate. |
| 9. | DNA transcribes genetic information to RNA. | RNA translates the transcribed message for forming polypeptides. |
| 10. | DNA controls heredity, evolution, metabolism, structure and differentiation. | RNA controls only protein synthesis. |
| 11. | DNA controls metabolism and genetics including variations. | It only controls metabolism under instructions from DNA. |
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