The ATP content of an average muscle fibre at rest is very low. Under short, high energy demand exercise (e.g. a 100 m sprint), the initially very low ATP levels in the muscle fibres are buffered by phosphocreatine (PCr, Figure 1). ATP ADP Н CHз Н CHз .N. N. 'N' 'N' .N. creatine kinase H' Н H. creatine phosphocreatine Fig.1 We can measure levels of phosphocreatine and ATP in a working tissue using 31P NMR spectroscopy, through the height of the corresponding NMR peak. Figure 2 shows the NMR-spectroscopy results of muscle intracellular fluid from a subject who had done 2 minutes of vigorous exercise. A: before exercise, B: first minute of exercise, C: last minute of exercise, D: after exercise; I, II and III are peaks that represent the three phosphate groups in ATP molecules, IV: PCr, V: Pi, VI: phospho-monoesters. IV III II II III' II o $ -10 -15 -20 ppm Fig.2 Immediately when the actin-myosin interaction starts producing ADP, the activity of the enzyme adeny- late kinase, which catalyses the near-equilibrium reaction 2 ADP + ATP + AMP becomes significant. Besides the generation of the negligible amount of available ATP, the reaction is essential because both ADP and AMP can allosterically upregulate glycolytic enzymes - and therefore prepare the muscle for longer exercise. I.

A.What is the Result of the sodium potassium ATPase activity in the cell? B.What mechanism does the sodium potassium ATPase use to achieve this result? C. Why is the above-mentioned change in affinity critical for the sodium potassium ATPase to perform its function?

1. a. Calculate the physiological DG of the reaction shown below at 37°C, as it occurs in the cytosol ofneurons, with phosphocreatine at 4.7 mM, creatine at 1.0 mM, ADP at 0.73 mM, and ATP at 2.6mM. The standard free energy change for the overall reaction is –12.5 kJ/mol. Phosphocreatine + ADP ® creatine + ATP b. The enzyme phosphoglucomutase catalyzes the conversion of glucose 1-phosphate to glucose6-phosphate. Calculate the standard free energy change of this reaction if incubation of 20 mMglucose 1-phosphate (no glucose-6 phosphate initially present) yields a final equilibrium mixtureof 1.0 mM glucose 1-phosphate and 19 mM glucose 6-phosphate at 25°C and pH 7.0.   c. If the rate of a nonenzymatic reaction is 1.2 x 10–2 μM s–1, what is the rate of the reaction at 37℃ inthe presence of an enzyme that reduces the activation energy by 30.5 kJ/mol?

Intravenous injection of KCl could be fatal. Why?

am. 206.

Describe the categories of enzyme control: (image provided) Allosteric control with example Covalent modification with example

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Which statements are true of an inhibitor that binds the active site of an enzyme? Select all that apply, there may be one correct answer or several.   a These inhibitors are a kind of allosteric regulator that decreases enzyme activity.    b Adding more substrate can reduce the effect of these inhibitors.   c These inhibitors compete with the substrate for the active site of the enzyme.   d These inhibitors increase the rate of enzyme activity.   e These inhibitors function by changing the shape of the enzyme, stopping if from binding to substrate.

a. Calculate how  many carbons from an original glucose molecule will enter into the TCA cycle? (please provide your answer in number like 1, 2, 3)   b. Based on the question you answered above what happens to the carbons that do not enter the cycle (write what it converts into)?

a. What is the efficiency of the metabolic conversion of palmitic acid to ATP? b. Compute the number of grams of palmitic acid that would have to be metabolized to provide the heat to warm a swimmer from whose skin 61 g of water evaporates.