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29 Cards in this Set
- Front
- Back
Net weight percentage of glycogen in Liver.
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6-8 %
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Net weight percentage of glycogen in muscle.
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1-2 %
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Type of glycogen particle seen in muscle
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Beta particle
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Type of glycogen particle seen in liver
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Alpha particle which appear as rosettes beta particles
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How much glycogenin per particle in liver and muscle?
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One each in both.
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How does glycogen play a role in the liver? What about during fasting?
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To maintain blood glucose levels. Releases glucose during fasting to supply tissues.
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How does glycogen play a role in muscle? What happens to the glycogen in muscle?
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Lowers blood glucose levels after feeding. Glucose never leaves muscles.
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What are the two major enzymes involved in glycogen degradation?
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1.) Glycogen phosphorylase
2.) Glycogen debranching enzyme. |
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What does glycogen phosphorylase do? What is the residue molecule?
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Phosphoyrlates (cleaves) at the NON-reducing end of the 1-4 linkage, releasing a residue of glucose 1 phosphate
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When does glycogen phosphorylase stop? What takes over afterwards?
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When there is four residues at the branchpoint. Afterwards, glycogen debranching enzyme takes over.
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What is the molecule called after complete digestion by glycogen phosphorylase?
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Limit dextrins
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What are the two enzyme activities associated with glycogen debranching enzyme on the same polypeptide?
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1.) 1,4 -> 1,4 glucan transferase.
2.) 1,6 glucosidase |
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1.) Alpha 1-4 -> 1-4 transferase activity transfers three residue branch to another chain.
2.) Glucosidase activity via hydrolysis 3.) Water 4.) Glucose |
Glycogen debranching enzyme activity
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How many isozymes of glycogen phosphorylase are there?
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2
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How many isozymes of glycogen debranching enzyme are there.
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None. Only one type exists
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How many isoforms exist for glycogen phosphorylase and glycogen debranching enzyme?
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Glycogen phosphorylase: many
Glycogen debranching enzyme: none is known |
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What does the variance is glycogen storage disease suggest?
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Although only one is known, there are probably multiple isoforms of glycogen debranching enzymes.
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In muscle, what does it produce for entry into glycolysis?
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glucose 6 phosphate
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What is the role of glucose 6 phosphatase?
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Converts glucose 6 phosphate to glucose?
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Where is glucose 6 phosphatase found?
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In ER membrane
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Glucose transport
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answers
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What does phosphoglucomutase do?
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Convert glucose 1 phosphate to glucose 6 phosphate
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What are the allosteric regulators of glycogen phosphorylase?
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Activator: AMP
Inhibitor: ATP, glucose, glucose 6 P |
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What enzyme activates glycogen phosphorylase?
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The b form of phosphoryase kinase.
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How does phosphorylase kinase become activated?
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Protein kinase phosphorylates the alpha and beta subunits of phosphorylase kinase to activate it.
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How is protein kinase activated?
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cAMP
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What is the delta subunit of prosphorylase kinase?
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calmodulin
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How does calcium affect glycogen?
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Ca increase will bind to calmodulin, thus activating it (whether alpha or beta activated or not).
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How can you maximize the activity of phosphorylase kinase?
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Phosphorylating alpha and beta by Protein kinase
AND calcium binding to calmodulin (delta subunit) |