A free particle (photon, electron etc) is not restricted to discrete energy levels. Its wavelength and therefore energy can take any value. A plane wave, with any wavelength you choose, can satisfy the Schrodinger equation for a single free particle. A free particle does not have to have a single precise energy. For example, a wave packet (a quantum wave that moves along like a fizzy ball) in free space has a range of energies. A particle that is confined will have discrete energy levels. For example, an electron in orbit around a nucleus. So quantum mechanics does not always mean that energy or any other property is quantized.
Cell Passage. Cell passaging or splitting is a technique that enables an individual to keep cells alive and growing under cultured conditions for extended periods of time.Cells should be passed when they are 90%-100% confluent. Ethanol squirt bottle and kimwipes.ell passaging or splitting is a technique that enables an individual to keep cells alive and growing under cultured conditions for extended periods of time. Cells should be passed when they are 90%-100% confluent. Ethanol squirt bottle and kimwipes.
cell membrane. The thin membrane that forms the outer surface of the protoplasm of a cell and regulates the passage of materials in and out of the cell. It is made up of proteins and lipids and often contains molecular receptors. The membranes of organelles within the cell are made of the same basic material as the cell membrane. In plant cells, the cell membrane is surrounded by a rigid cell wall. Also called plasma membrane. Compare cell wall. See more at cell.