When the Earth formed, it’s condition can best be described as:

Earth’s first atmosphere contained little or no:

Upload your answers to these questions. Outline the synthesis of the ketone body, acetoacetate, which forms in the liver under fasting conditions. It is formed in three steps. Include all substrate and product names and structures, enzyme names, and any necessary cofactors or coenzymes. (5 pts.) For the last step in the synthesis of acetoacetate, draw the arrow pushing mechanism for the reaction and identify which reaction in glycolysis it is parallel to. (3 pts.)  Ketone bodies are exported from the liver and utilized as an energy source by the extra-hepatic tissues. The brain, which normally utilizes glucose as its energy source, can, under fasting conditions, partially convert to using ketone bodies over the course of a few days. Show how a molecule of the ketone body, -hydroxybutyrate, produced in the liver and exported via the blood to the brain, is utilized for energy production and what advantage this compound has over acetoacetate in terms of cellular energy production. You may use compound names instead of structures. Enzyme names are not necessary. Include any necessary cofactors for full points. (3 pts.) 

Because the partial pressure of oxygen in the blood is lower than that in active muscle tissue, oxygen will naturally diffuse into muscle cells to help support their activity.

Upload your answers to these questions. Show how a molecule of palmitic acid (16:0) that has entered a muscle cell is tagged or prepared for β-oxidation in the cytosol. Write out the reaction. Include substrate and product structures, a general enzyme name, any intermediates, and all necessary cofactors. Cofactor abbreviations are OK. (4 pts.) Acetyl-CoA is a key metabolic intermediate. Write out the reactions that take one molecule of the tagged palmitic acid (16:0) in the matrix and release one molecule of acetyl-CoA. Give the generalized enzyme name or reaction type that describes each reaction in the pathway (dehydrogenase, hydratase, synthase, etc.), along with the name of the final enzyme that results in the formation of acetyl-CoA, as well as any intermediates and required cofactors or co-reactants. (5 pts.)

What cofactor or coenzyme is required for this reaction?

Which tense of a verb is used to: Narrate a series of past actions or events.

The expression:  Juan trabajó por su padre   means…

Upload your answers to these questions. Beginning with PLP (Vit. B6), whose structure is given below, draw out the arrow-pushing mechanism that results in the transfer of the amino group of Ala to PLP as catalyzed by the enzyme alanine aminotransferase. (4 pts.)  Name the molecule that ultimately accepts the amino group of Ala in the above alanine aminotransferase reaction. (1 pt.)  The α-amino group in the amino acid glutamate can be directly converted to an α-keto compound in a single step with the release of ammonia. This reaction requires a cofactor. Identify the cofactor and the general name for the type of enzyme that catalayzes reactions like these. (2 pts.) 

Upload your answers to these questions. In gluconeogenesis, oxaloacetate can be converted in a single step in the matrix of the mitochondria to an intermediate, which is not the final, but the penultimate (next to last) compound in glycolysis. Show this reaction. Draw the structure and name(s) of the product(s) of this reaction and give the name(s) or acceptable abbreviation(s) of any necessary cofactor(s) or co-reactants for the reaction, as well as the name of the enzyme that catalyzes this reaction. (3 pts.) When cytosolic NADH is insufficient to run the GAP dehydrogenase reaction in reverse, oxaloacetate can also be converted to the same penultimate glycolysis intermediate in the cytosol instead of in the matrix. Outline the set of reactions in this case, beginning with oxaloacetate in the mitochondrial matrix and ending with the formation of the penultimate glycolysis intermediate in the cytosol. Structures or names or acceptable abbreviations of compounds and cofactors are sufficient, but all substrates and cofactors must have either a structure or name given. (4 pts.)  Oxaloacetate connects to fatty acid biosynthesis via the reaction that forms the shuttle compound responsible for transferring fatty acid building blocks from the mitochondrial matrix to the cytosol. Draw out the reaction that synthesizes this shuttle compound. Draw the structure and name of the product(s) of the reaction and give the name(s) or acceptable abbreviation(s) of any necessary cofactor(s) or co-reactants for the reaction. (3 pts.)