A similar phenomenon occurs in cancer cells, where increased glucose utilization

Question

A similar phenomenon occurs in cancer cells, where increased glucose utilization is required as a source of energy and to support the increased rate of cell proliferation. Interestingly, across a tumor mass, interior cells may experience fluctuations in oxygen tension that in turn limit nutrient oxidation and become an important aspect for tumor survival. In addition, the increased glucose utilization generates high amounts of lactate, which creates an acidic environment and facilitates tumor invasion. Another factor that dramatically affects the metabolism is the nutritional status of the individual - for instance, during fasting or fed states. After a carbohydrate-rich meal, blood glucose concentration rises sharply and a massive amount of glucose is taken up by hepatocytes by means of GLUT2. This typ of transporter has very low affinmity for glucose and is effective only when glucose concentration is high. Thus, during the fed state the liver responds directly to blood glucose levels by increasing its rate of glucose uptake. In addition to being the main source of energy, glucose is utilized in other pathways, such as glycogen and lipid synthesis by hepatocytes. The hole picture becomes far more complex when we consider how hormones influence our energy metabolism. Fluctuations in blood levels of glucose trigger secretion of the hormones insulin and glucagon. How do such hormons influence the use of fuel of molicules by the various tissues? Hormones Regulate Cell Metabolism Human cells and tissues adapt to internal metabolic demands in many ways, mostly in responce to hormones and / or nervous stimuli. Demands by one cell type can be met by the consumption of its own reserves and by the uptake of fuel molecules released in the bloodstream by other cells. Enenrgy use is tightly regulated so that the energy demands of all cells are met simultaneously. Elevates levels of glucose stimulate pancreatic bete - cells to release insulin into the bloodstream. Virtually all cells respond to insulin; thus, during the fed state cell metabolism is coordinated by insulin signaling.

Explanation / Answer

cellular metabolism , hormones regulation and cancer or tumours ;

the two carbohydrates involves are the disacarides glucose and polysaccaride glycogen which is responsible for the storage , the main hormones responsible are insulin and glucagon . these hormones are inturn depend on two regulatoy enzymes of glycolysis and gluconeo genesis are hexokinase and glucokinase which are isozymes , gluokinase activity is seen the body where ,glycolysis should occur to produce energy ATP to the cell s producing the glucose 6 phospahate , when ever the glucose 6 phosphate are in high amount in the cells which result in activation of tissue specific hexokinase enzyme which converts the excess of glucose into the glycogen for storage the hormone which it activates is the glucagon . hexokinase traps the glucose into trapped inside the cell making it non ionic form . hexokinas eis restricted to certain types of tissues like adipose , cardiac muscles and thi salso has low K m value there is high level of expression of hexokinase is seen in the tummor cells because of lack of tumor supressor gene P 53, . in contrast the glucose kinase is having the high Km valve resulting it is expresased in hepatocytes and beta cells of pancreases . which have direct effect on hormone insulin . whenever the blood glucose is in rise the insulin hormone is secreted to breakdown the glucose into energy .whenever there is high level of glucose in the tissues resulting in the secretion of glucagon wher excess of glucose is converted into glycogen

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