Food,water,shelter,family,friends,and the most a friend to spend life with........
Natural selection because for example a bird with colors that camouflage it has a lower chance of being found than a bird with colors that make it easy to find. So the bird that easier to see will die more often.
Answer:
Permeable membranes allow anything to pass through.
Impermeable membranes have a poor permeable rate or nothing can pass through.
Semipermeable membranes select or allow only certain substances to pass through.
Explanation:
Permeable Membranes:
- Window screen - can pass water and air through 100%
- Mesh - can pass water and air through 100%
Impermeable Membranes:
- Clay - permeability rate is extremely low, and water cannot pass through
- Ziplock bag - nothing can come in or out
Semipermeable Membranes:
- Plant and Animal cell membranes (lipid bilayer) - only certain substances can pass through, like soluble vitamins
- Cell Organelle Membranes - only certain substances can pass through the mitochondria, for example
* 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
