Adhesion molecules are membrane proteins that form a link between the cytoskeleton inside a cell and the cell’s environment, which consists of other cells and the ECM. Far from being a simple “glue” that keeps cells together, adhesion molecules play an active role in virtually every aspect of animal development. Differential adhesive properties of cells [...]

Protoplasm is the fluid within plant and animal cells. The protoplasm surrounding the nucleus is known as the cytoplasm. The protoplasm within the nucleus is the nucleoplasm. The protoplasm is mostly water, and its average elemental composition is: Oxygen ………………….. .75 + Carbon ………………….. .10 + Hydrogen ………………….. .10 Nitrogen ………………….. .02 + Sulfur ………………….. [...]

The surface area to volume ratio restricts cell size. Large cells have less surface relative to a small cells. Large cells produce more waste, but have proportionately less surface area through which to expel that waste. This means that waste will build up inside the cell and kill the cell. In addition, large cells need [...]

Most cells are between 10 and 100 micrometers. 1 micrometer is 10,000 angstrom units. Structural Features of All Cells Chromosome The chromosome is cDNA in prokaryotes. For eukaryotes, there are two categories: introns and exons. Introns are the noncoding regions of DNA. The chromosome is stored within the nucleus. The chromosome is divided into supercoiling [...]