Question

Which of the evets is NOT caused by Interferon? Select all that apply. Perforin forms pores on the surface of the cell Host cell MHC-Il expression increases Host cell Poly(A)mRNA degrades Host cell protein synthesis decrease Host cell immunoproteasome expression increases

Answer 1

1.Answer- perforin forms pores on the surface of the cell.

Infected cells produce the interferon in response to the viruses.The infected cells release the protein kinase R enzyme induced by interferon which acts upon eIF-2 and phosphorylates ,further it binds to the eIF2B and reduces the protein synthesis.The RNAL is the cellular enzyme released in response to the interferon and degrades the poly A mRNA within the cell which causes the reduction in protein synthesis of host and viral gene.The interferon also increases the host cell MHCI and II expression and enhances the immunoproteosome expression.The perforin is located at the natural killer cells and cytotoxic T lymphocytes .It is involved in the pore formation at the target cell membrane and releases the cytolytic material for their destruction.

2. B and D

The calcitonin is produced by the parafollicular cells of the thyroid gland and helps in the maintenance of the calcium and phosphate level in blood.When calcium level becomes high in blood, the calcitonin starts secreting and inhibits the osteoclasts activity and enhances the osteoblast activity. The inhibition of the osteoblast activity, inhibits the calcium release from bone to blood due to reduced resorption of bone,thus decreases the calcium level in blood. The stimulation of osteoblast causes the calcium transfer from blood to bone.calcitonin stimulates the synthesis of vitamin D in kidney.

3.

a-Responds to FSH Sertoli cells b- Responds to LH Leydig cells C- Produces testosterone Leydig cells d- Produces ABP Sertoli cells e-Forms the blood-testis barrier Sertoli cells