Viroids differ from viruses in having RNA molecules without protein coat.

Viroids:
- Viroids are small, infectious RNA molecules that are devoid of a protein coat.
- They are the smallest known infectious agents and are composed solely of a short, single-stranded RNA molecule.
- Viroids do not possess any protein-coding genes and rely on the host cell's machinery for their replication.
- They cause various diseases in plants, interfering with the normal growth and development of the infected plant.

Viruses:
- Viruses are infectious agents that contain genetic material (either DNA or RNA) enclosed in a protein coat called a capsid.
- Viruses can infect a wide range of organisms, including animals, plants, and even bacteria.
- They are obligate intracellular parasites, meaning they require a host cell to replicate and carry out their life cycle.
- Viruses can have either DNA or RNA as their genetic material, but they always have a protein coat.
- The protein coat, or capsid, protects the genetic material and aids in the virus's attachment to host cells.

Difference between Viroids and Viruses:
1. Genetic Material:
- Viroids: Viroids contain only RNA as their genetic material.
- Viruses: Viruses can have either DNA or RNA as their genetic material.

2. Protein Coat:
- Viroids: Viroids do not possess a protein coat.
- Viruses: Viruses always have a protein coat called a capsid.

3. Protein-Coding Genes:
- Viroids: Viroids do not contain any protein-coding genes.
- Viruses: Viruses may contain protein-coding genes in addition to their genetic material.

4. Replication:
- Viroids: Viroids rely on the host cell's machinery for their replication.
- Viruses: Viruses also require the host cell's machinery for replication but may have additional enzymes to aid in their replication.

5. Infectivity:
- Viroids: Viroids primarily infect plants and cause diseases in them.
- Viruses: Viruses can infect a wide range of organisms, including animals, humans, plants, and bacteria.

Conclusion:
In summary, viroids differ from viruses in that they are composed solely of RNA molecules without a protein coat, while viruses have genetic material (DNA or RNA) enclosed in a protein coat. Viroids primarily infect plants and do not contain protein-coding genes, relying on the host cell for replication.

Viroids differ from viruses in having:
There are several key differences between viroids and viruses. Viroids are infectious agents that are composed solely of RNA molecules, while viruses are composed of both DNA or RNA molecules and a protein coat. Viroids are simpler in structure compared to viruses, lacking the protein coat found in viruses.
Here are the main differences between viroids and viruses:
1. Composition:
- Viroids: Viroids consist of single-stranded RNA molecules without a protein coat.
- Viruses: Viruses can contain either DNA or RNA molecules, which are surrounded by a protein coat called a capsid.
2. Size:
- Viroids: Viroids are smaller than viruses, typically ranging from 246 to 467 nucleotides in length.
- Viruses: Viruses are larger than viroids and can vary greatly in size, ranging from 20 to 300 nanometers.
3. Replication:
- Viroids: Viroids replicate within the host cell's nucleus using the host cell's enzymes.
- Viruses: Viruses require a host cell to replicate and often use the host cell's machinery for replication.
4. Disease-causing ability:
- Viroids: Viroids are known to cause diseases in plants, such as potato spindle tuber disease and citrus exocortis.
- Viruses: Viruses can infect a wide range of organisms, including humans, animals, and plants, and are associated with various diseases.
In conclusion, viroids differ from viruses in having RNA molecules without a protein coat, whereas viruses have either DNA or RNA molecules with a protein coat.