Question

how can i differentiate necrosis and apoptosis?

Answer 1

in mutiple ways: in necrosis cells swell (As they lose ATP sources which disrupt among other the NaKATPase pump that maintains membrane potential). in apoptosis cells become smaller - pyknotic.
DNA condensation and fragmentation (easy to see on a slide, even without specialized stains).
in necrosis cell contents spill outside (insulin in beta cells will be seen outside of cells).
apoptosis - u may see blebs of membrane early on.
speciazlied stains: as apoptosis is more molecularly coordinated - u can stain for these signals, among them - are caspases (Ca serine proteases that orchestrate the process). TUNEL assay - which is really cool BTW - that stains for DNA ends. in a normal cells u\ll see 23*2*2. chromosomes*chromatides*ends. in an apoptotic cell as DNA breaks ull get thousnads of breaks - hence signal amplification. there is yet another stain for membranous phospatidyl serine if i remember correctly - aposense is the name of the company that manufactures the kit.

Answer 2

necrosis is the death of cells or tissues from severe injury or disease, especially in a localized area of the body. Causes of necrosis include inadequate blood supply (as in infarcted tissue), bacterial infection, traumatic injury, and hyperthermia.

apoptosis is a
natural process of self-destruction in certain cells, such as epithelial cells and erythrocytes, that are genetically programmed to have a limited life span or are damaged. Apoptosis can be induced either by a stimulus, such as irradiation or toxic drugs, or by removal of a repressor agent. The cells disintegrate into membrane-bound particles that are then eliminated by phagocytosis. Also called programmed cell death .