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Genetica

    Retrovirus contain viral RNA and several copies of reverse transcriptase (DNA polymerase). After infecting a cell, the reverse transcriptase is used to make the initial copies of viral DNA from viral RNA. Once a DNA strand has been synthesized, a complementary viral DNA strand is made. These double strand copies of viral DNA are inserted into the host-cell chromosome and host-cell RNA polymerase is used to make virus-related RNA. 

   These RNA strands serve as templates for making new copies of the viral chromosomal RNA and serve also as mRNA. mRNA is translated into viral proteins that are used to make the virus envelope. New viral particles are assembled, bud from the plasma membrane, and are released. An example of this process is illustrated in the replication of the retrovirus, HIV (human immunodeficiency virus).


    

     Functionarea si reproducerea Hiv poate infecta doar celule care suporta molecula CD4 pe citoplasma, una dintre aceste celule fiind CD4 T-Lymphocytes(o celula alba din sange).Ajutat de lipidele di citoplasma Hiv se prinde si apoi se inglobeaza in celula,apoi ARNul di nucleu se tranforam in ADN.



     In majoritatea cancerelor, celulele tumorale activeaza o molecula numita TELOMERAZA. Telomeraza nu este activata si in cazul celulelor sanatoase, cu exceptia celulelor stem. Functia telomerazei este sa adauge telomeri ADN-ului celular atunci cand acesta se scurteaza in urma unei diviziuni. De aceea aceste celulele nu pierd telomeri in cazul diviziunii.

    Asta sugereaza ca , odata gasita o metoda de a ucide telomeraza in celulele canceroase , telomerii se vor scurta treptat si celula tumorala va muri.


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