This set of Virology Question Bank focuses on “Human Viral Diseases – Carcinogenesis and Tumor Viruses”.
1. Which of the following factor does not contribute to virus-associated oncogenesis?
Explanation: Various factors such as host genotype, age at infection, diet, environmental carcinogens (other than viruses), and other invading organisms, may all contribute to the process od virus-associated oncogenesis.
2. Which of the following enzyme maintains the ends of the chromosome?
Explanation: Telomerase is an enzyme that maintains the ends of the chromosome. Telomerase maintains the size of the chromosome otherwise it would result in the reduction in length of the chromosome that leads to senescence.
3. Which of the following may occur due to transformation?
b) Weight loss
d) Weight gain
Explanation: Mutations may occur due to transformation which leads to change in DNA base pairs. There is now evidence that the mechanisms underlying immortalization, transformation, and tumorigenesis involve the alteration to a cell’s DNA, which is a mutation.
4. Oncogenes are ______________
a) anemia genes
b) cancer genes
c) thalassemia genes
d) color blindness genes
Explanation: Oncogenes are genes that cause cancer. They promote tumor formation if they sustain mutations that alter protein products or increase their level of expression. They are also involved in controlling cell signaling and regulation of the cell division cycle.
5. Which of the following causes Kaposi’s sarcoma?
Explanation: HHV-8, a herpes virus, causes Kaposi’s sarcoma in humans. It affects people with immunodeficiencies such as HIV or AIDS. Lesions may appear on the skin, lymph nodes, mucous membranes, etc.
6. Which of the following causes warts?
a) Human papilloma type 16
b) Bovine papilloma type 4
Explanation: Bovine papilloma type 4 causes warts and fibroepithelioma in cattle, hamsters, and rabbits. It is a type of papillomavirus and may affect the newborn. It is one of the most extensively studied papillomavirus.
7. Which of the following protein is synthesized by human papilloma for cell transformation?
Explanation: Human papillomavirus (HPV) synthesizes E6 and E7 proteins implicated in cell transformation. The same proteins are also required for tumorigenesis. They are essential for normal virus replication in their natural target cells.
8. Which of the following protein can fully transform the baby rat kidney (BRK) cells alone?
a) E1A of human adenovirus
b) E1B of human adenovirus
c) Large T antigen of SV40
d) Middle T antigen of polyoma
Explanation: Large T antigen of SV40 alone can transform baby rat kidney (BRK) cells. Whereas E1A and E1B of human adenovirus both are required for transformation. Similarly, polyomavirus large T and middle T antigen are the need for full transformation by this virus.
9. ATL is a tumor of ___________
Explanation: Adult T cell leukemia (ATL) is a tumor of CD4+ T lymphocytes. ATL cells always contain integrated HTLV-1 DNA in a minority of those infected. The distribution of ATL cases across the globe is nonuniform with hot-spots in Japan and the Caribbean Islands.
10. Carcinoma is the cancer of lymphoid tissue.
Explanation: Carcinoma is the cancer of epithelial tissue. In this, the cells that make up the skin or the tissue lining start dividing uncontrollably and destroy the body tissue. The cancer of lymphoid tissue is known as lymphoma.
11. Benign tumor invades into other tissues.
Explanation: Benign is used to describe the growths which do not infiltrate into the surrounding tissues. It does not invade into other tissues whereas malignant invade into other tissues, both being opposite of each other.
Sanfoundry Global Education & Learning Series – Virology.
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