Exam 11: Chemical Logic of Metabolism

A futile cycle is:

Which of the following can be used as a metabolic control mechanism?

The anabolic and catabolic processes of cellular metabolism can be coupled by ATP.

Reactions in metabolic pathways that are subject to regulation are those that are displaced far from ________.

Which of the following produces the largest number of reducing equivalents when oxidized?

Name the type of reaction that involves reversible electron transfer from a donor to an acceptor.

Under physiological conditions the complete oxidation of glucose to carbon dioxide and water in the presence of oxygen has a △G of -2900 kJ/mol glucose. This process can be coupled to the synthesis of ~32 mol ATP. The △G of the coupled reactions to make ATP is -1300 kJ/mol glucose. Calculate the △G for the synthesis of ATP from ADP.

The standard free energy change in physiological conditions (△G∘') for the reaction catalyzed by malate dehydrogenase in the citric acid cycle malate + NAD+ oxaloacetate + NADH + H+ is ~+29 kJmol-1 Calculate the actual △G' at 37∘C if Keq' is 1.02 × 10-5

Calculate the amount of ATP in kg that is turned over by a resting human every 24 hours. Assume that a typical human contains ~50g of ATP (Mr 505) and consumes ~8000 kJ of energy in food each day. The energy stored in the terminal anhydride bond of ATP under standard conditions is 30.6 kJmol-1. Assume also that the dietary energy is channeled through ATP with an energy transfer efficiency of ~50%.

Catabolic processes involve degradation of complex molecules into simpler molecules with the net release of chemical energy.

An enzyme that catalyzes a committed step in a metabolic pathway has a high ________.

ATP has a high phosphoryl group transfer potential because:

Substrate-level phosphorylation is a term given to the loss of free energy when ATP is hydrolyzed.

The main energy-coupling compound in biochemical reactions that allows thermodynamically unfavorable processes to become favorable is ________.

Enzyme-catalyzed sequential reactions that make up a metabolic pathway are normally separated in the cell for equal access to reactants.