Meat stored energy into muscle power. The two most abundant myofibrillar proteins, myosin and actin, are responsible for the muscle's overall structure. The remaining protein mass consists of connective tissue (collagen and elastin) as well as organelle tissue. Fat in meat can be either adipose tissue, used by the animal to store energy and consisting of "true fats" (esters of glycerol with fatty acids), or intramuscular fat, which contains considerable quantities of phospholipids and of unsaponifiable constituents such as cholesterol. Meat can be broadly classified as "red" or "white" depending on the concentration of myoglobin in muscle fibre. When myoglobin is
Keratin about 10 µm across, with cores and coating, and may be arranged in up to 10 layers, also in plaques of variable shape. Adult hornets also use silk as a glue, as do spiders. Some infectious fungi, such as those that cause athlete's foot and ringworm (i.e. the dermatophytes), or "Batrachochytrium dendrobatidis" (Chytrid fungus), feed on keratin. Diseases caused by mutations in the keratin genes include: Keratin expression is helpful in determining epithelial origin in anaplastic cancers. Tumors that express keratin include carcinomas, thymomas, sarcomas and trophoblastic neoplasms. Furthermore, the precise expression pattern of keratin subtypes allows prediction of the