Proteins in a membrane are C. Both answer choice is true.
Explanation:
Membranes have different types of proteins. <em>Peripheral proteins are the ones that are placed on the inside suface held in place by the cytoskeleton. Integral proteins are the ones that are embedded in the membrane and protrude from either surfaces of the bilayer. </em>These integral proteins also can be carrier proteins, which facilitate passage of molecules through the membrane
; enzymatic proteins, whichcatalyze a specific reaction or they can recognize pathogens, baing cell recognition proteins. In the membrane we can find aquaporins too, which are membrane channel proteins that enable water to cross a membrane.
Peripheral proteins and integral proteins are a type of membrane proteins that play a vital role in signal transduction, enzyme activity, cell adhesion and transportation of molecules.
Peripheral proteins are attached to the lipid bilayer temporarily at either one side of the lipid bilayer and can be easily dissociated from the lipid bilayer when treated with polar solution. It plays an important role in transportation, maintaining the shape of the cell as well as signal transduction.
Integral proteins span the two sides of the lipid bilayer and are attached to it permanently, it can only be detached by the treatment with non polar solutions. It plays an important role in cell adhesion and transportation.
Acetylcholine is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle.
However, norepinephrine, gamma aminobutyric acid, and cholinesterase are not excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle.
Using the receptors on their surface and through the facilitation by immunoglobulins that attach to the foreign matter, macrophages 'hold' the foreign bodies in the body and 'ingest' them through phagocytosis. Lysozymes in the cells then in 'digest' the foreign matter.
