What is the MOST important factor causing most species to go extinct today? _______

A secondary spermatocyte is diploid.

Which structure is involved in erection of the penis?

To establish a persistent infection, viruses evade many aspects of innate and adaptive immunity. Examples of viral immune evasion strategies are described below. For each strategy, please state whether virally-infected cells (i.e. the ‘target cell’) would be killed by: i) virus-specific CTLs and/or ii) NK cells, and explain why target cell killing by these lymphocytes would or would not occur, for these responses do not consider ADCC reactions. Write 1-2 sentences each part, using the format below (you just need to write A, B, and C and i and ii. A) HIV often harbors mutations in the sole viral epitope presented by MHC class I, resulting in loss of viral peptide binding to the MHC I. i) Virus-specific CTLs: ii) NK cells:  B) Human cytomegalovirus (HCMV) encodes a protein called US3 that binds to MHC Class I molecules and retains them in the ER, so that they are never presented on the cell surface. i) Virus-specific CTLs:  ii) NK cells: C) Poxviruses encode a protein called crmA, which can inhibit caspases 3 and 8. i) Virus-specific CTLs:  ii) NK cells:  

Male circumcision involves removing which structure?

Mark the following statements as True or False. Food and drink are always allowed in the lab.

Which of the following biogeochemical cycle is run almost entirely by living organisms, and especially by prokaryotes?

Sound can be defined as:

HSV shedding is decreased in persons with HIV as compared to persons without HIV due to treatment with anti-retrovirals.

Chromosomes are made of