Human red blood cells are flattened disks indented on eitherside; muscle cells are highly elongated; neurons are long and thin with many branches on each end; and white blood cells constantly change their shapes as they crawl through the body.
Cells are also often depicted as a bag of fluid with a smattering of structures within, but this is far from the truth. Instead, the interior of the cell is a dense network of structural proteins, collectively termed the cytoskeleton, within which is embedded a large collection of organelles. The material within the cell except for the nucleus is called the cytoplasm. The nonorganelle portion of the cytoplasm is called the cytosol. The consistency of the cytoplasm is much like egg white, and not at all like freely flowing water.
Membranes
Eukaryotic cells include large amounts of membrane, which enclose the cell itself and surround each of the organelles. The membrane surrounding the cell is termed the plasma membrane. Membranes are bilayered structures, made of two layers of phospholipid molecules, built from phosphoric acids and fatty acids. One end of the phospholipid molecules (the exterior head) is hydrophilic, and it is oriented to the outer side of the membrane; the other end (the interior tails) are hydrophobic.
This is a free page. This page contains 196 words. This
article contains 2,385 words (approx. 8 pages at 300
words per page).
Read the rest of this Article with our Cell, Eukaryotic Access Pass.
