1.0 1.0 0.8 0.8 ScPfk 0.6 0.6 ScPfk 0.4 0.4 YIPfk 0.2 0.2 2 4 6 8 P-enolpyruvate (mM) 10 23 20 50 100 10 15 Fructose-2,6-P2 (µM) Relative activity (v V-1) Relative activity (v V-1)

Consider the malate dehydrogenase reaction, part of tricarboxylic acid cycle, shown below. malate + NAD+ oxaloacetate + NADH + H+ ΔGo ’ = 29.7 kJ/mol. It has been reported that the concentrations of NAD+ and NADH in yeast mitochondria were 20 mM and 0.3 mM, respectively. If we performed similar measurements and also determined that the concentration of malate in yeast mitochondria was 0.5 mM and that of oxaloacetate was 0.1 µM at pH 7.0 at 37˚C, use this information to calculate the free energy of the reaction of yeast in mitochondria.

Corticosteroids (a type of hormone), and Nonsteroidal Anti-inflammatory Drugs (NSAIDs) are non-narcotic pain relievers. Both medications are prescribed to reduce inflammation in the body.  NSAIDs such as aspirin, acetaminophen, and ibuprofen are able to reduce pain, fever, and inflammation by blocking the action of the cyclooxygenase enzyme (COX) that catalyzes the conversion of arachidonic acid into prostaglandins. Common corticosteroids include prednisone, cortisone, and methylprednisolone.  Choose one of these three corticosteroids.  The corticosteroid that you choose and then explain how the drug works to reduce inflammation.

Consider the malate dehydrogenase reaction, part of tricarboxylic acid cycle, shown below. malate + NAD+ oxaloacetate + NADH + H+ ΔGo ’ = 29.7 kJ/mol. It has been reported that the concentrations of NAD+ and NADH in yeast mitochondria were 20 mM and 0.3 mM, respectively. If we performed similar measurements and also determined that the concentration of malate in yeast mitochondria was 0.5 mM and that of oxaloacetate was 0.1 µM at pH 7.0 at 37˚C, use this information to calculate the equilibrium constant for the given reaction.

Strategies for regulating the central pathways in carbohydrate metabolism vary among different cells in one organism and among organisms.  Slight changes in the regulation of enzymes in central metabolism can effectively re-route metabolite traffic through these pathways, just like a small mutation in PFK-1 can convert a healthy cell into a cancerous one.   For instance, Gillaspera mold uses an alternative strategy for regulation the TCA and glycolysis.   Gillaspera contains a unique isocitrate dehydrogenase that has an allosteric site for citrate.  High citrate inhibits isocitrate dehydrogenase in this organism.   Gillaspera also lacks a citrate binding site on PFK-1, so this variant of the enzyme is not affected by citrate concentrations at all.   Gillaspera lacks the enzymes ethanol dehydrogenase and lactate dehydrogenase and no carbons are lost in its unique fermentation product.   Would high glucose in these organisms lead to production of carbon dioxide from glucose catabolism?…

Can you please pick the right answer in each parentheses?   The pentose phosphate pathway provides a number of critical functions including     ["production of ribose-5-phosphate", "production of NADH"]   that is vital for     ["synthesis of nucleotides and coenzymes", "oxidative phosphorylation"] .   This pathway is divided into oxidative and non-oxidative steps.  The latter steps    ["are involved in the conversion of various sugar phopshates, so called  ["carbon shuffle reactions"", "are directly involved in NADPH production"] .   If   ["NADP+", "NAD+"]   levels are high, flux through the pentose phosphate pathway is promoted by allosteric regulation of glucose-6-phosphate dehydrogenase.  If reducing equivalents derived form the pentose phosphate pathway are high, glucose-6-phosphate is directed toward   ["a phosphatase and then export from the cell", "glycolysis"]            .

Malate dehydrogenase is an enzyme that converts malate to oxaloacetate in the last stage of the TCA Cycle (citric acid cycle/Krebs cyde), represented by the following equation: NAD+ Malate Oxaloacetate NADH A group of students carried out an experiment to determine the optimum temperature for the activity of a commercially produced malate dehydrogenase (from yeast) at several different temperatures. A series of test tubes was set up containing 2.0 cm of phosphate buffer with a pH of 7.5, 0.1 cm? of NADH, 0.1 cm of malate dehydrogenase and 0.7 cm3 of water. The tubes were incubated in water baths at the various temperatures for 5 minutes. At certain time intervals each tube was placed in a colorimeter, set at an absorbance value of 1.0. The reaction was then started by adding 0.1 cm? of oxaloacetic acid to the tube. Enzyme activity was measured by following the decrease in absorbance for 120 seconds. The experiment was repeated to give duplicate results. Enzyme activity was then…

A solution of [U 14C] glucose-1-phosphate (specific activity = 16,000 cpm/mmole) was  incubated with glycogen and glycogen phosphorylase, an enzyme which adds glucose units on to  glycogen. Radioactivity was incorporated into the glycogen primer at a rate = 2550 cpm/min. The rate  of the enzymatic reaction in units of mmole glucose incorporated per minute is:  (a) 0.016 mmol/min  (b) 0.57 mmol/min  (c) 0.16 mmol/min  (d) 5.7 mmol/min

ATP synthase is a protein that catalyzes the formation of the energy storage molecule adenosine triphosphate using adenosine diphosphate and inorganic phosphate. Which of the following are true for the protein, ATP synthase? Select all apply A mutation of Asp61 to glutamic acid would have less of a deleterious effect on its ability to synthesize ATP than a mutation of Asp61 to alanine A mutation of Asp61 to alanine would have less of a deleterious effect on its ability to synthesize ATP than a mutation of Asp61 to glutamic acid The F1 subunit is primarily responsible for translocating H+ ions across the inner mitochondrial membrane during ATP synthesis The FO subunit is primarily responsible for translocating H+ ions across the inner mitochondrial membrane during ATP synthesis

Explain the purpose of the glycerol 3 phosphate shuttle (Don’t worry about the mechanism, just the purpose of the shuttle. Just one sentence here!). Suppose a cell could only rely on the glycerol 3 phosphate shuttle and not the malate-aspartate shuttle, how would that affect the amount of ATP that could be generated from the complete oxidation of 1 molecule of glucose in that cell? How would this change the amount of ATP that could be generated from the complete oxidation of 1 molecule of palmitate in this cell?