BIO201 Final Term Solved Papers Spring 2021

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BIO201 Cell Biology

FINAL TERM

CURRENT PAPERS

SPRING 2021

Oncogenes : An oncogene is a gene that has the potential to cause cancer. In tumor cells, these genes are often mutated, or expressed at high levels. LDL Particles : (3) Low-density lipoprotein particles (LDL-P) are bi-products of fat transport that remain in circulation for an extended time. While in circulation, LDL-Particles can penetrate the artery wall and get stuck, forming a fatty plaque. These plaques can build over time and lead to blockages, resulting in heart attacks and strokes.

•  Normal LDL size (> 25.5 nm, Normal LDL group)
•  Small LDL (</= 25.5 nm, Small LDL group)

Housekeeping Cells : (3) In cell biology, housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular function and are expressed in all cells of an organism under normal and patho-physiological conditions. Examples :

•  Aactin
•  GAPDH
•  Ubiquitin

Functions of T cells : (3)

•  T cells are responsible for cell-mediated immunity
•  T cells directly killed infected host cells
•  T cells are the helper cells that activating other immune cells
•  T cells producing cytokines
•  T cells regulating the immune response
•  T cells are the helper cells that defence against both extracellular and intracellular pathogens.

Epigenetics : (2) The study of heritable changes in gene function that do not involve changes in DNA sequence but they can change how body reads a DNA sequence. Epigenetic changes alter the physical structure of DNA. Example : DNA methylation Phagocytosis : (2) Phagocytosis is a process by which particles, microbes or fragments of dead cells are engulfed and internalized, usually by specific membrane receptors. OR Phagocytosis is a process by which certain living cells called phagocytes ingest or engulf other cells or particles. The phagocyte may be a free-living one-celled organism such as an amoeba or one of the body cells such as a white blood cell. Cytokinesis : (2) Cytokinesis is a physical process of cell division, that normally takes place after mitosis. Cytokinesis is the physical division of the cell cytoplasm, the cell membrane, and cell