Answer:
The correct answer will be option-C
Explanation:
The CsCl gradient centrifugation in Meselson Stahl experiments is done to separate the bands of the DNA containing isotopes on the basis of difference in the density.
In the experiment, bacterial cultures were grown in the medium of 15N and 14N but if we repeat the experiment with P32 and P31 instead of 15N and 14N and centrifugation is performed then the banding pattern will be the same as of the previous experiment as the method of the replication is same that is semi-conservative.
Thus, Option-C is the correct answer.
Answer:
The answer is <em><u>D.
</u></em>
Explanation:
Viruses can evade the processing and presentation of antigens, for example by interfering with the expression of MHC class I proteins, although this increases their susceptibility to be detected by natural killer cells (NK). However, some members of the herpesvirus, papillomavirus, retrovirus, poxvirus and flavivirus families have also developed strategies to escape the attack of NK cells and promote their survival, inhibiting cell apoptosis. Finally, some pathogens often change surface antigens frequently, as in the case of influenza viruses (orthomyxovirus).
The human immunodeficiency virus (HIV) affects CD4 + T cells and degrades the host's ability to counterattack with a strong cell-mediated immune response. There are so many tactics of immune evasion used by HIV, which have so far hindered the development of an effective vaccine.
A cell with a nucleus. The opposite is a prokaryote; a cell without a nucleus.
