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BCH 361 EXAM 4
Where does glycogen store glucose? - correct answer ✔✔Liver and muscle What is glycogen? - correct answer ✔✔Highly branched polymer of glucose What does liver do with glycogen? - correct answer ✔✔Breaks down glycogen and releases glucose to the blood to provide energy for the brain and red blood cells What does muscle store glycogen for? - correct answer ✔✔Energy for muscle contraction Subunit and bonds of glycogen - correct answer ✔✔-alpha glucose -alpha 1,4 and 1,6 bonds Subunit and bonds of starch - correct answer ✔✔Amylose -alpha glucose -alpha 1, Amylopectin -alpha glucose -alpha 1,4 and 1, Subunit and bonds of cellulose - correct answer ✔✔-beta glucose -beta 1, Glycogen phosphorylase - correct answer ✔✔Degrades glycogen from the non-reducing ends to form glucose 1-phosphate Phosphoglucomutase - correct answer ✔✔Converts glucose-1-phosphate to glucose-6-phosphate with the use of glucose 1,6-bisphosphate
Debranching enzyme - correct answer ✔✔Transferase shifts a small oligosaccharide away from the branching point and alpha 1,6-glucosidase removes a alpha 1,6 linked glucose Phosphorylase a - correct answer ✔✔More active than phosphorylase b R state - correct answer ✔✔More active than T state Muscle phosphorylase - correct answer ✔✔Regulated by intracellular energy charge. In muscle, default form is the b form, in the T state (less active). The T state is stabilized by ATP and glucose-6-phosphate. Liver phosphorylase - correct answer ✔✔Regulated by glucose level. In liver, default form is the a form, in the R state (active). Glucose is a negative regulator of liver phosphorylase. Phosphorylase kinase - correct answer ✔✔Converts glycogen phosphorylase from the unphosphorylated b state to the phosphorylated a state. Activated by phosphorylation and calcium binding. Phosphorylated by protein kinase A. What hormones are used in glycogen degradation? - correct answer ✔✔Glucagon and epinephrine. Glucagon released by alpha cells in the pancreas in response to low blood sugar. Epinephrine released by adrenal glans in response to muscle activity and stress. G protein signal transduction - correct answer ✔✔Glucagon and epinephrine initiate G protein cascades that produce cAMP. Cyclic AMP activates protein kinase A, which phosphorylates phosphorylase kinase, which converts glycogen phosphorylase from the b to a form which activates glycogen degradation. How is glycogen chain synthesized? - correct answer ✔✔Using UDP-glucose - Uridine diphosphate glucose UDP-glucose is a glucose donor - correct answer ✔✔UDP-glucose pyrophophorylase synthesizes UDP- glucose from Glucose 1-phosphate and UTP
Summary of Pentose Phosphate Pathway - correct answer ✔✔Conversion of 3 pentoses into 2 hexoses ( fructose 6-phosphate) and 1 triose (Glyceraldehyde 3-phosphate) Pentose phosphate can be produced through 2 modes - correct answer ✔✔Oxidation of glucose 6- phosphate with production of NADPH and conversion from the intermediates of glycolysis, F6P and GAP. Mode 1 - correct answer ✔✔Need more Ribose 5-phosphate than NADPH (phase 2 of PPP) Mode 2 - correct answer ✔✔NADPH and ribose 5-phosphate needs are balanced (phase 1 of PPP) Mode 3 - correct answer ✔✔Need more NADPH than ribose 5-phosphate. 1 glucose 6-phosphate + 12 NADP+ + 7 H2O -> 6 CO2 + 12 NADPH + 12 H+ + Pi Mode 4 - correct answer ✔✔NADPH and ATP both required Gluthathione - correct answer ✔✔Glutathione (GSH) helps to prevent damage by reactive oxygen species. Required to maintain the normal structure of hemoglobin.
