Why is the glycolytic pathway central to cell metabolism, and which step in the glycolytic pathway is the committed step?
Describe the 3 pathways of pyruvate metabolism.
Why are phosphorylated intermediates of glycolysis important? What specifically are the functions of the phosphoryl groups of these intermediates?
Under what conditions is phosphofructokinase 1 activated, and under what conditions is it inactivated?
What is a kinase? Provide 3 examples wherein a kinase is important in the metabolic pathway.
What is galactosemia? How does it occur, and what are the symptoms?
Under what conditions is lactate formed? Is there a net change in the oxidation state of carbon when glucose is converved to lactate through two oxidation-reduction steps?
Laypersons often use the term “oxygen debt”. Using your text and any available web resources, briefly explain oxygen debt in biochemical terms.
D-fructose can undergo glycolysis after being phosphorylated and cleaved to glyceraldehyde and dihydroxyacetone phosphate. What source of D-fructose would humans most commonly encounter?
There are two end products of the oxidative reactions of the pentose phosphate pathway. Name them and identify an end point for each, i.e. what roles these two products might eventually play.
In figure 14-21 note that phosphopentose isomerase catalyzes the reaction which ends in the product D-Ribose 5-phosphate. In plant systems, the enzyme phophopentose epimerase is encountered. This would catalyze Ribulose 5-phosphate to yield ____________________?
In the nonoxidative reactions of the pentose phosphate pathway, transketolase is a TPP-dependent enzyme. What is TPP (literally and functionally), and what would happen in the pathway if no TPP was available?
Glucose is the primary and preferred source for energy for and during normal central nervous system activity. What types of physiological conditions might create a biochemical environment whereby lactate would be preferred over glucose? Read the following article to aid in formulating your answer: Bliss TM and Sapolsky RM . (2001) Brain Research, 899 (1,2): 134-141.
Locate and read the following article: Liang Q, Donthi RV., Kralik, PM, and Epstein PN. (2002) Cardiovascular Research , 53 (2): 423-430. Propose an explanation as to why the glycogen content of the hearts of the transgenic mice was elevated. What enzyme also demonstrated increased levels?
Describe the structure of coenzyme A focusing on the components of the molecule. What is its function? [2]
Why are thioesters good donors of acyl groups? What exactly are thioesters? [2]
What is the source of energy for steps 1 through 3 of the overall pyruvate dehydrogenase complex reaction? [2]
Describe how the different enzyme subunits of pyruvate dehydrogenase interact with their cofactors to catalyze decarboxylation of pyruvate. [3]
How is the pyruvate dehydrogenase complex regulated through covalent modification? [3]
What function do the lipolysyl moieties of the second enzyme in the pyruvate dehydrogenase complex serve? [2]
What is the overall purpose of the citric acid cycle, and where do its reactions take place in eukaryotic organisms? [2]
What is the net energy yield per molecule of glucose for the combined reactions of glycolysis, the pyruvate dehydrogenase reaction and the citric acid cycle? [2]
Under what circumstances is pyruvate carboxylase activity stimulated? [2]
Why is citrate synthase a good candidate for a regulatory enzyme? [3]
Define the term amphibolic pathway and explain how the Citric Acid Cycle meets the criteria. [2]
Which steps of the Citric Acid Cycle are irreversible? [2]
Name an alternative fate of succinyl-CoA in the absence of succinyl-CoA synthetase. [2]
Oxidation of isocitrate and alpha-ketoglutarate release carbon atoms and thus produce energy. How is this energy conserved for later use in the cycle? [2]
Explain why the coordinated regulation of isocitrate lyase and isocitrate dehydrogenase is advantageous to an organism. [4]
Adipose tissue utilizes acetate to synthesize triglycerides. Why can cells not use acetate as a precursor for synthesizing glucose, as is seen in plants, bacteria and fungi? [3]
Using the web and your UF library resources, identify a disorder or disease associated with deficiency of one of the regulatory enzymes or co-factors of the Citric Acid Cycle. Describe the symptoms of the disorder/disease and how it might be treated, if at all. [5]
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