Use of the reverse transcriptase enzyme is a unique characteristic of retroviruses such as HIV. After the virus releases its genetic material into a host cell, reverse transcriptase converts the viral RNA into a complementary piece of DNA, a process is known as ‘reverse transcription’.
Reverse transcriptase works by looking in turn at each of the nucleoside building blocks that make up the viral RNA and using them as a template to assemble a complementary DNA chain using nucleotide building blocks present in the cell.
Virusurile sunt entitati infectioase complexe si organizate, deoarece contin doua componente esentiale: una genetica
(acidul nucleic) si una
. Uneori, proteinele nu sunt esentiale pentru exprimarea proprietatilor sistemului, pentru ca acidul nucleic in stare pura este infectios.
organizat al virionului rezulta din faptul ca relatiile spatiale dintre genom si capsida sunt definite si constante si deriva din simetria la nivel
The function of the immune system is to protect animals from foreign agents and infectious organisms. It responds in a specific way to pathogens and
displays a long term memory of earlier contacts with the disease agents. The immune system consists of two functional components:
Non-specific defence (innate or non adaptive immune system)