What is the difference between a rock and a mineral? A rock is composed of combinations of minerals, each mineral having its own chemical formula and crystalline structure. Minerals are composed of an element or combination of eâ¦lements. Granite, for instance, is an intrusive igneous rock composed of the minerals quartz, feldspar, mica, hornblende, and other combinations or ratios of minerals.
Colloblasts are a cell type found in ctenophores. They are widespread in the tentacles of these animals and are used to capture prey. Colloblasts consist of a coiled spiral filament that is embedded in the epidermis and an axial filament with a granular dome.The apical surface of these cells consist of eosinophilic granules that are thought to be the source of adhesion.On contact, these granules rupture, and release an adhesive substance onto the prey. The spiral filament absorbs the impact of the rupture, preventing the ensnared prey from escaping.he apical surface of these cells consist of eosinophilic granules that are thought to be the source of adhesion. On contact, these granules rupture, and release an adhesive substance onto the prey. The spiral filament absorbs the impact of the rupture, preventing the ensnared prey from escaping.
The colloblast appears to be a disposable capture cell and a new scheme of its organization is proposed. LITERATURE CITED AFZELIUS, B. A., 1969. Ultrastructure of cilia and flagella. Pages 1219-1242 in A. Lima-de-Faria, Ed., Handbook of molecular cytology.lthough the helical thread is loosely coiled for the first two turns, it later tightens before heading towards the center of the colloblast head. The diameter (0.25-1.25 u), length and number of turns of the helical thread vary with the origin of the colloblast.