I need help to understand the fully correct answer in detail. This is my exam an

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I need help to understand the fully correct answer in detail. This is my exam and I am studying for finals as I want to grasp this material very well. Please very detailed information is good.

In answering the following short answer questions you should beasupecific and detailed as your evey of undentandungallows Whenever possible, support youranswers with details eviden exa es to illustrate your explanations and use correct biological terminology 45. 12 pts. Choose ONE of the following signaling processes and the physiological function of the process in the context of the organism, 2) describe 1) or other membrane components, signaling the molecular mechanisms including the receptors molecules, etc.. involved, 3) the specific cellular response and physiological effect occurs and 4) how termination of the signal is accomplished. You may use a diagram if you must provide a detailed written response. you attempt to answer more than one, you must clearly indicate which response you would like graded. A) Stimulation of skeletal musce cells by the nervous system C) Change in of OR arterial smooth muscle by epinephrine signaling blood glucose levels in response to insulin signaling. D) Attachment and internalization of a pathogen during infection of a human cell When an animal eats some the glucose levels in blood rise due to absorption of toed molecules in tu the blood strea m h glucose levels aie bad and can damage plus, needs to be way Store ey tra. 6 ga glucose. The stor ef glucose anN lhe uphekt of glucose is mndreas secretes fnsulin. Insulin binds started rs on the surlave ,of the membrane of cells. n to be p Gr P acts like at? but i erway spifkaily activit ny tranprrt pote, ns. the tiemport n hat insulin nd Sugar molewles into the ceN fur this in turn brags s' ls down in blood staen

Explanation / Answer

Change in blood glucose levels in response to insulin signaling

Insulin acts on specific receptors located on the cell membrane of every cell,but their density depends on the cell type,:liver and fat cells r very rich.The insulin receptor is a receptor tyrosine kinase which is a heterotetramic glycoprotein consisting of 2 extracellular alpha & 2 transmembrane beta subunits linked together by disulfhide bond .The alpha subunit carry insulin binding site, while beta subunit have tyrosin protein kinase activity. It is oriented across the membrane as a dimer.

Binding if insulin to alpha subunits induces aggregation & internalisation of d receptor along wid d bound insulin molecule. THIS ACTIVATES TYROSINE KINASE ACTIVITY OF D BETA SUBUNITS - pairs of beta subunit phosphorylate tyrosine residues on each other - expose d catalytic site to phosphorylate tyrosin residues of insulin receptor substrate proteins. In turn, a cascade of phosphorylation and dephoshorylation rxns is set into motion which amplifies d signal & results in stimulation and inhibition of enzymes involved in d rapid metabolic actions of insulin.

Certain 2nd messengers like phosphatidyl inositol triphosphate which r generated thru activation of a specific PI 3- kinase also mediate d action of insulin on enzymes.

Insulin stimulates glucose transport across cell membrane by ATP dependent translocation of glucose receptor GLUT 4 to d plasma membrane. The 2nd messenger PIP & certain tyrosin phosphorylated guanine nucleotide exchange proteins play imp. role in translocation of GLUT 4 frm cytosol to plasma memb. ,espically in skeletal & adipose tissue. Over a pd of tim insulin also promotes expression of GLUT 4. Genes for a large no: enzymes & carriers r regulated by insulin thru Ras/Raf & MAP- Kinase as well as thru d phosphorylation cascade. Long term effects of insulin r exerted by generation of transcription factors promoting proliferation & differentiatn of specific cells.   

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