what is the g protein? and where it found and what is the exact function of it and is there any specific types

Answer 1

G proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. They are so called because of their signaling mechanism, which uses the exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP) as a general molecular "switch" function to regulate cell processes
A common way to translate a signal to a biologic effect inside cells is by way of nucleotide regulatory proteins (G proteins) that bind GTP. GTP is the guanosine analog of ATP . When the signal reaches a G protein. The GTP-protein complex brings about the effect. The inherent GTPase activity of the protein then converts GTP to GDP, restoring the resting state. The GTPase activity is accelerated by a family of RGS (regulators of G protein signaling) proteins that accelerate the formation of GDP.

Small G proteins are involved in many cellular functions. Members of the Rab family of these proteins regulate the rate of vesicle traffic between the endoplasmic reticulum, the Golgi apparatus, lysosomes, endosomes, and the cell membrane . Another family of small GTP-binding proteins, the Rho/Rac family, mediates interactions between the cytoskeleton and cell membrane, and a third family, the Ras family, regulates growth by transmitting signals from the cell membrane to the nucleus. The members of these three families are related to the product of the ras proto-oncogene.

Another family of G proteins, the larger heterotrimeric G proteins, couple cell surface receptors to catalytic units that catalyze the intracellular formation of second messengers or couple the receptors directly to ion channels. These G proteins are made up of three subunits designated α, β, and γ . The α subunit is bound to GDP. When a ligand binds to a G-coupled receptor, this GDP is exchanged for GTP and the α subunit separates from the combined β and γ subunits. The separated α subunit brings about many biologic effects. The β and γ subunits do not separate from each other, and βγ also activates a variety of effectors. The intrinsic GTPase activity of the α subunit then converts GTP to GDP, and this leads to reassociation of the α with the βγ subunit and termination of effector activation.

Heterotrimeric G proteins relay signals from over 1000 receptors, and their effectors in the cells include ion channels and enzymes. There are 16 α, 5 β, and 14 γ genes, so a large number of subunits are produced, and they can combine in various ways. They can be divided into five families, each with a relatively characteristic set of effectors. The families are Gs, Gi, Gt, Gq, and G13.

Many G proteins are modified by having specific lipids attached to them, i.e. they are lipidated. Trimeric G proteins may be myristolated, palmitoylated, or prenylated. Small G proteins may be prenylated.

Answer 2

there is lots Creationism can't account for. As for the micro organism, a creature that could survive on what killed its ancestors isn't an occasion of speciation? Then how with reference to the primroses, Tragopogon, Hemp Nettle, and so on., advert very almost infinitum? We SEE speciation going on, yet they go with to miss approximately it. They declare that Lucy nevertheless has Chimpanzee features (which isn't actual - Chimps have retained some features that we've not), then declare that there is not any transitional. yet why are we adults arguing with babies? (have no concern - i think of it's going to be a quantity trillion years till now you at the instant are no longer an unbeliever - by way of the certainty that entropy stops increasing.)

Answer 3

proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. They are so called because of their signaling mechanism, which uses the exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP) as a general molecular "switch" function to regulate cell processes.