Explain how mutations in the following proteins might result in either loss of responsiveness to a given hormone or production of a continuous signal even in the absence of the hormone a defect in a G protein that renders the GTPase activity inactive

Normally, when blood glucose level increases (e.g. after a meal), the islet cells in the pancreas secrete insulin. When insulin molecules bind to insulin receptors on the surface of a muscle cell, the receptors become activated, initiating a signaling pathway which eventually results in the increase in the number of passive glucose transporter on the muscle cell surface thus increases the uptake of glucose into the cell and decrease blood glucose level. Indicate whether the following conditions/practice will likely lead to diabetes (mark Yes or No). [Select] degeneration of islet cells [Select] [Select] [Select] a mutation in the insulin receptor that increases its kinase activity ✓ exercise a mutation in the insulin receptor that prevents dimerization

Thyroid peroxidase iodinates tyrosine residues within the thyroglobulin protein, and this enzymatic reaction occurs in the cytoplasm of follicular cells of the thyroid gland.  True  False.  Although the thyroid gland releases far more thyroxine (T4) that triiodothyronine (T3), it is T3 that is the active hormone that regulates gene expression in target cells.  True  False In Gravesâ disease, circulating levels of both thyrotropin releasing hormone (TRH) and TSH are very low compared to a normal person.  True  False I do not need explanation. I need just the answer.

Ligand binding to proteins may occur with varying strengths; some ligands bind tightly to proteins while others bind less tightly. The strengths of reversible binding are determined experimentally by varying concentrations of ligands, and measuring the saturation of the protein in the various ligand concentrations. One such laboratory study investigated the binding of a hormone to three different receptor proteins in the cell membrane. The data collected are shown in the table below: 1) Provide a brief explanation as to why ligand binding to proteins must be a reversible process.  2)  Calculate the dissociation constant (Kd) for the hormone binding to each of the three proteins.

Steroid hormones are required by the body at puberty and into adolescence to regulate growth and cell division at more rapid pace than in later life.  This regulation occurs via their interaction with cellular receptors and the signaling cascades/pathways that follow.  Describe for me the difference between the two major classes of steroids, anabolic and catabolic steroids.  What might you expect the result of signaling cascades to be in cells receiving either anabolic or catabolic “signals”? (B) At some point in late adolescence, steroid production decreases by almost 100 fold, as we transition into “adulthood”.  Why might we wish to stop these signals from constantly being in our blood stream, (like, Say, between 17-24 years of age)?  What result might these steroids have on cancer cells where abhorrent signaling is already causing an increased rate of cell division/growth? Could steroid use result in Cancer?

Epinephrine stimulates glycogen breakdown by activating glycogen phosphorylase. However, in the research lab, no glycogen breakdown occurred when epinephrine was added to a test tube containing the enzyme and its substrate, glycogen. Explain why glycogen phosphorylase could be activated by epinephrine only when the hormone was added to intact cells in a solution.

1) the Ga subunit has a mutation resulting in increased GTPase activity? Why is the GPCR referred to as a GEF? What would occur in G protein signalling if

Explain how vinclozolin acts as an endocrine disrupter.

Identify the incorrect statement: O A. Steroid hormones, such as testosterone, are derived from cholesterol and regulate cell function by influencing transcription. O B. Melatonin is a hydrophobic steroid hormone synthesized by the pineal gland It regulates the circadian rhythm of the cell OC. Catecholamines are hydrophilic hormones synthesized from tyrosine. Therefore, membranes are barriers to them, and their receptors need to be on the extracellular surface. O D. Antidiuretic hormone is a peptide hormone that regulates fluid balance in the body O E. Thyroid hormone is a hydrophobic tyrosine derived hormone that regulates the metabolism,

Describe the difference between agonist and antagonist. What is a role of    G-protein coupled receptors?