Exam 12: Chemical Logic of Metabolism

The phosphorylation of creatine (Cr)by ATP forming creatine phosphate (Cr-P)is rather endergonic ( $\Delta$ G°´ = + 12.6 kJ/mol). Which of the following explains how this reaction proceeds in a typical muscle cell?

Which of the following would be considered a biosynthetic pathway?

Which of the following functional groups is commonly the electrophile in nucleophilic acyl substitutions?

During the oxidation of glucose within a typical animal cell, reduced electron carrier such as NADH are produced. What is the terminal electron acceptor of the electrons carried by NADH?

________ is commonly used as an oxidizing agent in catabolic pathways while ________ is commonly used as a reducing agent in anabolic pathways.

Which of the following types of reactions best describes the formation of a peptide bond?

The formation of a hemiacetal when glucose undergoes cyclization represents what type of reaction?

In stage ____ metabolism, a catabolic pathway might produce ________ while the opposing anabolic pathway might produce _________.

Many enzyme-catalyzed reactions that transfer a phosphate from one molecule to another utilize a histidine residue in the active site of the enzyme. The histidine participates in covalent catalysis by performing a nucleophilic attack on a phosphate, forming an intermediate phosphohistidine (the phosphate covalently attached to the histidine residue). Using ATP as the phosphate donor, show the reaction to form the phosphohistidine intermediate-you do not have to show arrow pushing.

Which of the following represents a correct compartmentation of a biochemical process with its cellular location?

Which of the following types of reactions best describes the reaction shown below?

Complete oxidation of glucose by burning in a calorimeter gives a $\Delta$ G°´ of -2870 kJ/mol. If we assume this to be the maximum energy that can be extracted from glucose, what is the percent of energy that is captured in a cell given that about 32 ATP can be made from a single molecule of glucose? $\Delta$ G°´ for ATP hydrolysis is -30.5 kJ/mol while $\Delta$ G for ATP hydrolysis in a cell is about -51 kJ/mol.

The glycolytic reaction fructose-6-phosphate + ATP $\rarr$ fructose-1,6-bisphosphate + ADP Has an ATP-coupling coefficient of _____ while the gluconeogenic reaction Fructose-1,6-bisphosphate + H₂O $\rarr$ fructose-6-phosphate + P_i Has an ATP-coupling coefficient of _____.

Which of the following pairs of pathways, if active at the same time, would be considered a futile cycle?

Molecules that are produced inside a cell in response to a hormone binding to its receptor are called _________.

Pyruvic acid has the formula C₃H₄O₃. Write the reaction for its complete combustion. What is its respiratory quotient? Does this mean that it is more oxidized or less oxidized than glucose?

What is the oxidant in the following reaction?

Based on the following reaction, what is the respiratory quotient for stearic acid? C₁₈H₃₆O₂ + 26 O₂ $\rarr$ 18 CO₂ + 18 H₂O

Of the following, which would have the most reduced state of carbon, and therefore, would yield the largest amount of energy per gram?

Which of the following functional groups is a commonly seen nucleophile in biochemical reactions?