How many places are there for electrons in the second shell of an atom? The answer is C) 8 electrons
Answer:
d. eon, era, period, epoch
Explanation:
The geological time scale has been made so that the scientists can have a practical system about the classification of geological time, thus everything that has happened throughout it. The geological time unites have been defined in accordance with important events that have happened, thus marking their end or beginning. These events can be mass extinctions, catastrophes, climate patterns, domination of certain species etc. The longest of these time units is the eon, lasting for more than half a billion years, and up to 2 billion years. The era comes as the second longest time unit, lasting for several hundred million years. The period lasts for several tens of million years, and the epoch is the smallest unit, lasting for few million years, or several hundred thousand years.
0.393701 <span>inches makes a cm</span>
* More than 40 proteins and glycoproteins involved in the complement system are synthesized by the liver, macrophages, epithelial cells, they are present in the blood in plasmatic form, membrane, some have an enzymatic activity, regulator or membrane receptorThese are elements of the humoral innate immune response, they fight infections, purify immune complexes and apoptotic bodies.
<span>There are indeed three ways to activate the complement:</span>
Classical pathway: Activated by Immunoglobulins in immune complexes, aggregated Immunoglobulins, DNA, CRP, apoptotic bodies .......it involves nine fractions, starting with C1, then C4, C2, C3, to form a classical C5 convertase, then, activation of C5, C6, C7, C8, C9.
Alternative pathway: activated by polysaccharides (bacterial endotoxin), vascular wall poor in sialic acid, aggregated IgE ...C3b like is the first component in the alternate channel cascade, it will create an amplification loop, and form an alternative C5 convertase.
Lecithin pathway: Activated by mannose, fucose (carbohydrate of microorganisms)The first component is the complex MBL / MASP1 / MASP2: "mannose-binding protein": works according to the same principle as the complex C1 of the classical way (MASP2 cleaves the C4 and the rest of the cascade is equivalent to that of the classical way).
the three ways have the same outcome: A C5 convertase (formed by one of the pathways) cleaves C5 into C5a and C5b: C5b is deposited far from other fractions on the antigenic surface. The fixation of C5b in the cell is followed by that of C6, C7, C8, and C9 (9 molecules of C9): formation of the membrane attack complex (MAC) ==> Death of the cell by osmotic shock
