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22 Cards in this Set
- Front
- Back
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What cells are restricted to anaerobic degradation of glucose and why?
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Cells without O2 or mitochondria. Such as skin, exercising muscle, intestinal mucosa, large cancerous tumors and RBCs.
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What is the first step in glycolysis?
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Conversion of glucose to glucose 6-phosphate by hexokinase or glucokinase. Requires ATP. Irreversible. This steps keeps glucose in cell.
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What is considered the major, controlled rate limiting, irreversible rxn in glycolysis?
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Phosphorylation of F6P into F-1,6- BP by phosphofructokinase-1. Uses ATP.
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What is the role of aldose in glycolysis?
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Cleavage of F-1.6-BP into DHAP and GAP.
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What is the role of 3-P isomerase?
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Converts DHAP to GAP. If absent, pt will suffer from anemia.
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Draw out the steps of glycolysis
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Draw out the steps of glycolysis
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Draw out the steps of glycolysis
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***
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What is the final step of glycolysis?
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PEP catalyzed by pyruvate kinase to ATP and Pyruvate
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Where can arsenic disrupt in the glycolysis pathway?
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Glyceraldehyde 3-P Dehydrogenase (Glyceraldehyde 3-P to 1,3 bis-phosphoglycerate)
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Where can fluoride interfere with glycolysis? How is this used clinically?
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Fluoride inhibits enolase (2 phosphoglycerate to PEP). Lab tubes testing for serum glucose all contain F- to prevent glycolysis.
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How can NAD+ be regenerated?
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Anaerobic -- Pyruvate + NADH <--> Lactate + NAD+. Aerobic -- Lactate degraded to NADH+CO2+H2O and NADH enters e- transport chain to generate ATP.
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What are the possible metabolites of pyruvate?
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Oxaloacetate, Acetyl CoA, alanine and lactate.
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What is the energy yield of one mol of glucose? In the presence of O2?
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2ATP + 2NADH + 2 Pyruvate. In aerobic glycolysis linked with TCA you will yield 32 molecules of ATP.
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What substance can cause allosteric inhibition of hexokinase?
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G-6-P
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What substance can cause allosteric inhibition and activation of Phosphofructokinase-1?
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Activation: AMP and F2,6-bisP
Inhibition: ATP and low pH |
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What substance can cause allosteric inhibition and activation of pyruvate kinase?
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Activated by F-1,6-BP and inhibited by ATP
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What is fructose 2,6-bisphosphonate? How is it synthesized?
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Allosteric effector of PFK-1. It is generated through catalyzation of F6P by PFK-2.
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What is the role of PFK-2 in the liver?
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Activated by F6P and inhibited by Protein kinase A under fasting conditions. (protein kinase A is activated by cAmp whose synthesis is induced by binding of glucagon).
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What activates PFK-2 in the muscle?
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Activated by AMP and NE.
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Explain the biochemical reactions that produce pathology in aldolase deficiency. What can correct it?
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Aldolase cleaves F1P into GAP and DHAP. If not cleaved = overformation of F1P by fructokinase which leads to ATP overuse and accuml. of AMP. Degrading AMP leads to uric acid formation which competes with lactic acid for excretion. Lactic acidemia ensues as well as hypoglycemia (GAP is intermediate in glycolysis and gluconeogenesis). Tx: Eliminate fructose from diet!
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What mneumonic can help remember the order of enzymes in glycolysis?
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High Profile People Are Too Glamorous, Picture Posing Every Place
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