Selasa, 18 Oktober 2011

Cancer Cells

Cancer cells are cells that grow and divide at an unregulated, quickened pace. Although cancer cells can be quite common in a person they are only malignant when the other cells (particularly natural killer cells) fail to recognize and/or destroy them.

In the past a common belief was that cancer cells failed to be recognized and destroyed because of a weakness in the immune system. However, more recent research has shown that the failure to recognize cancer cells is caused by the lack of particular co-stimulated molecules that aid in the way antigens react with lymphocytes.

Sabtu, 15 Oktober 2011

Cell Membrane Theory

Cell membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells.

It consists of the phospholipid bilayer with embedded proteins. Cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity and cell signaling and serve as the attachment surface for the extracellular glycocalyx and cell wall and intracellular cytoskeleton.

Sabtu, 01 Oktober 2011

Parasitism Science Theory

Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with life stages that went beyond one host, which are now called macro parasites.

Parasites can now also refer to micro parasites, which are typically smaller, such as viruses and bacteria and can be directly transmitted between hosts of one species.