Differential screening
process in development of a multicellular organism by which cells become specialised for particular functions. Requires that there is selective expression of portions of the genome, the fully differentiated state may be preceded by a stage in which the cell is already programmed for differentiation but is not yet expressing the characteristic phenotype determination.
Stems primarily provide plants structural support. This tutorial includes lectures on the external form of a woody twig ..
Lentic or still water communities can vary greatly in appearance -- from a small temporary puddle to a large lake. The s..
Viruses possess both living and non-living characteristics. This unique feature distinguishes them from other organisms...
Molecules move within the cell or from one cell to another through different strategies. Transport may be in the form of..
This tutorial recognizes the importance of food as a source of energy that will fuel many biological processes. A good d..
Humans are diploid creatures. This means that for every chromosome in the body, there is another one to match it. Howeve..