2. In muscle tissue, the rate of conversion of glycogen to glucose 6-phosphate is determined by the ratio of phosphorylase a (active) to phosphorylase b (less active). Determine what happens to the rate of glycogen breakdown if a muscle preparation containing glycogen phosphorylase is treated with (a) phosphorylase kinase and ATP; (b) PP1; (c) epinephrine. 3. Between your evening meal and breakfast, your blood glucose drops and your liver becomes a net producer rather than consumer of glucose. Describe the hormonal basis for this switch, and explain how the hormonal change triggers glucose production by the liver.

2. In muscle tissue, the rate of conversion of glycogen to glucose 6-phosphate is determined by the ratio of phosphorylase a (active) to phosphorylase b (less active). Determine what happens to the rate of glycogen breakdown if a muscle preparation containing glycogen phosphorylase is treated with (a) phosphorylase kinase and ATP; (b) PP1; (c) epinephrine. 3. Between your evening meal and breakfast, your blood glucose drops and your liver becomes a net producer rather than consumer of glucose. Describe the hormonal basis for this switch, and explain how the hormonal change triggers glucose production by the liver.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 3P

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What is the rationale for the inhibition of muscle glycogen phosphorylase by glucose 6- phosphate when glucose 1- phosphate is the product of the phosphorylase reaction?
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Assuming that all the glucose entering a muscle fiber is oxidized, as what molecule will the glucose carbon leave the body? Of glucose’s six carbons, two oxidized carbon byproducts will be produced by one enzyme, and four will be produced by a metabolic pathway. At which enzyme and pathway are these carbon-based bi-products produced?
Muscles may become hypoxic during the early stages of exercise, causing lactate to build up. a) Describe in detail how a lack of oxygen might cause lactate to build up in the muscles. b) Explain how lactate (typically thought of as a waste product) may be converted to glucose via gluconeogenesis.
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Protein Phosphatase 1: What overall effect does PP1 have on the storage or breakdown of glycogen? (1 point) How does PPI regulate the activity of its targets? (1 point) Which enzymes are its targets? (2 points) What activates it [hormone (pathway activator) and enzyme (immediate activator)]? (2 points) Hormone: Enzyme:
What type of regulation would be expected when anaerobic metabolism is occurring in the muscle? Select all that apply. O Activation of pyruvate dehydrogenase kinase O Increased levels of calcium to activate pyruvate dehydrogenase phosphatase O Phosphorylation of pyruvate dehydrogenase O Inhibition of pyruvate dehydrogenase complex O Increased levels of NADH to activate citrate synthase O Increased levels of NADH to inhibit alpha-ketogluterate dehydrogenase complex O Increased levels of acetyl CoA to activate pyruvate carboxylase for gluconeogenesis
22. For this question, you may want to analyze Fig. 16.25 on your book. Adrenaline stimulates glycogen breakdown in skeletal muscle cells by ultimately activating glycogen phosphorylase, the enzyme that breaks down glycogen, as depicted in the figure below. adrenaline. activated GPCR (adrenergic receptor) Answer: Explanation: activated adenylyl cyclase inactive PKA inactive phosphorylase kinase ATP CAMP ADP activated a subunit of stimulatory G protein (G₁) active PKA inactive glycogen phosphorylase GTP ATP cyclic AMP ATP ADP CYTOSOL active phosphorylase kinase active glycogen phosphorylase ELE GLYCOGEN BREAKDOWN Which of the following statements is false? A) A constitutively active (i.e., always expressed) mutant form of PKA (cyclic AMP-dependent phosphorylase kinase) in skeletal muscle cells would lead to a decrease in the amount of unphosphorylated phosphorylase kinase. B) A constitutively active mutant form of PKA in skeletal muscle cells would not increase the affinity of…
After the training of marathon, lactic acid is accumulated in the athlete's thigh muscle. Compare the physiological functions and Vmax of glycogen phosphorylase in actively working skeletal muscle and that in liver After vigorous exercise, the athlete faints due to low blood glucose level. A liver biopsy test shows excess amount of glycogen is present in the liver. Suggest with explanation, which type of enzyme is defective in this case.
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