Answer:
Blood clothing is an example of positive feedback.
This type of feedback mechanism is useful to the body because it multiplies the factor that intervenes in clotting accelerating the process.
If a toxin affects the molecules that signal for platelets the feedback will not be effective enough to produce clotting and the body will keep bleeding.
Explanation:
Blood clotting is an example of positive feedback due to the fact that when the vascular endothelium is damaged platelets will go to this area and activate themselves once they are in contact with the collagen fibers of the damaged structure. When the platelets are activated they will release the contents that is stored in their granules. One of the contents is a Gq-linked protein receptor cascade, that will increase the concentration of calcium in the platelets. Calcium activates protein kinase C, which, in turn, activates phospholipase A2 (PLA2). PLA2 will modifies an integrin membrane increasing its affinity to bind fibrinogen. The activated platelets change their shape , and the fibrinogen cross-links with the integrin membrane aiding in the aggregation of adjacent platelets. After this the coagulation cascade takes place. there are two pathways the extrinsic and the extrinsic one.
The extrinsic pathway will be activated due to tissular factor released by the platelets and the intrinsic pathway will be activated due to endothelial collagen. The final product of both pathways is factor x.
Factor x will transform prothrombin into thrombin will activate the conversion of fibrinogen into fibrin. Thrombin will form a net of fibrin that will the clot.
A cascade reaction is useful because every component of the cascade are related making a quick reaction once that one of then is activated and can activate other or more factors.
If a toxin affects the molecules that signals for platelets, platelets will not go to the damaged area and in consequence there will not be thrombin and fibrin to form the clot together with platelets.
Nope, because they serve no purpose on earth
Answer:
Homo erectus
Explanation:
Homo erectus is believed to be the first creature walk erect and possibly be the first hominin
There are not several examples of thermal equilibrium, but only one case: Equal temperature everywhere and constantly along time, with no heat transfer. ... Then, leave the time pass and any inner temperature gradient will disappear by inner heat transfer until temperature is uniform and constant.
Answer:
this gene is a mitochondrial gene and therefore it is maternally inherited
Explanation:
The MT-ND5 gene is a gene of the mitochondrial genome that provides instructions for synthesizing a protein called NADH dehydrogenase 5, which is part of the complex I (the first enzyme of the respiratory chain). In most multicellular organisms, the mitochondrial DNA (mtDNA) is inherited from the mother (i.e., maternally inherited), whereas nuclear DNA (i.e., nuclear genome) is inherited equally from both parents. For example, mitochondria in human sperm are usually destroyed after fertilization. In consequence, mitochondrial mutations are transmitted by maternal inheritance, and individuals, therefore, cannot be heterozygous for mitochondrial genes.
