Concept explainers
Insulin is a large, water-soluble hormone that binds to receptors on the outside surface of muscle, fat, and several other cell types. Insulin binding to its receptors activates proteins that in turn stimulate or inhibit many enzymes inside the cell. One of the activated enzymes starts a cascade of reactions inside the cell, with the result that glucose-transporting proteins are moved to the plasma membrane. Once in the plasma membrane, the transport proteins facilitate the diffusion of glucose into the cell.
Insulin is essential to regulate
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Biology
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- A normal LDL (low-density lipoprotein) signaling pathway is shown in the image. Familial hypercholesterolemia is a disorder caused by a defect in the LDL receptors on the plasma membrane. What would be the consequence of this defect on the cell? The cell would increase production and exportation of HDL to remove LDL from the bloodstream. Additional LDL receptors without the defect would be formed and added to the plasma membrane. Increased fluidity of the plasma membrane would allow more water-soluble molecules to pass into the cell. The cell would produce greater amounts of ATP so that LDL could enter the cell through active transport instead of receptor-mediated endocytosis.arrow_forwardMatch the following molecules with their functions. Molecules CAMP Protein kinase A Glycogen phosphorylase Phosphoglucomutase Functions Converts glucose 1-P to glucose 6-P Phosphorylates a substrate using an inorganic phosphate Second messenger that can activate downstream proteins Phosphorylates a protein using ATParrow_forwardGiven insulin's structure, where is its target likely located? Insulin's adverse side effects include headache, nau- sea, hunger, confusion and weakness. What can these symptoms be attributed to? Insulin has major effects on muscle and adipose tissue. It increases the rate of glucose transport across the cell membrane, decreases the rate of lipolysis, and increases uptake of triglycerides and some amino acids from the blood. In doing so, what metabolic processes does it favor? Carbohydrates: Lipids: Proteins:arrow_forward
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