Viroids are naked DNA that cause disease in plants
True
False
The correct answer and explanation is:
The correct answer is False.
Viroids are not composed of DNA, but rather consist of small, circular RNA molecules that are capable of causing diseases in plants. Unlike typical viruses, viroids lack a protein coat, which is why they are considered “naked” RNA. These RNA molecules are much smaller than the average viruses and do not encode proteins. Instead, they replicate within plant cells and interfere with the normal cellular processes, often disrupting the plant’s ability to grow or function properly.
Viroids primarily cause diseases in plants by interacting with the host’s transcription and replication machinery. Their replication typically occurs in the nucleus or chloroplasts of the plant cells, depending on the species of the viroid. These RNA molecules are able to hijack the plant’s RNA polymerase, which is responsible for synthesizing RNA, and use it to replicate their own RNA genomes. The replication process can lead to the production of abnormal RNA molecules that interfere with the normal gene expression and biochemical processes in the plant.
The diseases caused by viroids are often characterized by symptoms such as stunted growth, yellowing of leaves, or deformation of the plant. These symptoms vary depending on the type of plant infected and the specific viroid strain involved. For example, the Potato spindle tuber viroid (PSTVd) causes diseases in potato plants, while other viroids affect species like citrus, tomatoes, and coconut palms.
In conclusion, viroids are not made of DNA but are instead composed of RNA. They are distinct from viruses and cause plant diseases by disrupting cellular mechanisms rather than by encoding proteins. This makes them unique in their structure and behavior in comparison to more traditional infectious agents.