Simulation · Biology · Class 11
Build an infectious agent
From the lesson Viroids, prions and lichens in Biological Classification. Change the values and watch what happens.
Build an infectious agentBiology · Class 11
The idea behind it
NCERT §2.6
- T.O. Diener (1971) discovered the viroid, an infectious agent smaller than a virus that causes potato spindle tuber disease.
- A viroid is free RNA with no protein coat, which is what separates it from a virus; its RNA is of low molecular weight.
- Prions are infectious agents made of abnormally folded protein, about the size of viruses, that transmit certain neurological diseases.
- Prion diseases include bovine spongiform encephalopathy (BSE, mad cow disease) in cattle and its human counterpart, Creutzfeldt-Jakob disease (CJD).
- Lichens are symbiotic, mutually useful associations between algae and fungi. The algal partner is the phycobiont (autotrophic) and the fungal partner is the mycobiont (heterotrophic).
- In a lichen the alga makes food for the fungus, while the fungus gives shelter and absorbs water and mineral nutrients for the alga. The two are so closely joined that a lichen looks like a single organism.
- Lichens are very good indicators of pollution because they do not grow in polluted areas.