BIOL 121 Lecture Notes - Lecture 7: Circular Rna, Metabolic Waste
Document Summary
Enhances reproductive success in changing environments: disadvantages: Viruses (latin word virus: toxin or poison: sub-microscopic particles [20-300 nm] smaller than a bacterium, consist of genetic material (nucleic acid [ss or ds; dna or rna]) contained within a protective protein coat called a capsid. Do not contain all 4 biomolecules: do not have a cellular structure (= basis for life, unable to replicate outside of a living system. [viruses do not reproduce: they infect the cells of living organisms [incl. bacteria] = (cid:862)infectious agents(cid:863) because they cause disease. Viroids: infectious particle of plants, smaller than viruses. Do not have cellular structure: depend upon enzymes of plant host for replication, lack proteins, - consist of a small rna molecule (usually single-stranded circular. Rna molecule of several 100 nucleotides in length: - unlike viruses, rna of viroids do not code for any proteins. Eating infected beef causes croutefeldt-jacob disease (cjd) & other diseases in humans.
