Viroids: Possibly the Smallest Pathogens on Earth

Viroids are the smallest known pathogens, consisting of a simple RNA strand without a protein coat. Initially discovered in potatoes, they are now known to affect various crops. Unlike viruses, viroids replicate using the host's RNA polymerase and can act as ribozymes. They are significant in agriculture due to their impact on crops and potential transmission through tools and insects. While they don't infect humans, viroids are crucial for understanding the origins of life, supporting the RNA world hypothesis, which suggests life began with RNA before DNA and proteins evolved.

What makes viroids distinct from viruses?

• They have a protein coat.

• They contain DNA.

• They lack a protein coat and have minimal RNA.

• They are larger than viruses.

How do viroids replicate within a host plant?

• By using the host's DNA polymerase.

• By directly converting RNA to DNA.

• By using the host's RNA polymerase.

• By creating their own proteins.

Which of the following crops is NOT mentioned as being affected by viroids?

• Bananas

• Apples

• Avocados

• Potatoes

What hypothesis suggests that life on Earth began with RNA?

• Protein world hypothesis

• DNA world hypothesis

• RNA world hypothesis

• Viroid world hypothesis

Why are viroids considered important for studying the origins of life?

• They provide insights into early RNA-based life forms.

• They have complex protein structures.

• They are the only pathogens that infect humans.

• They are the largest known pathogens.