Key Concepts in Electron Transport and Urea Cycle

Which component of the electron transport chain is also found in the citric acid cycle?

Complex II

Almost all of the oxygen (O2) one consumed in breathing converted to:

Water

Which of the following is false regarding ubiquinone?

It is an electron carrier that transports electrons from complex I and III to complex II.

Which statement is NOT true of electron transfer?

The mobile electron carrier coenzyme A is located in the inner mitochondrial membrane.

During the operation of the malate-aspartate shuttle, what process does NOT occur?

Transfer of amino groups from glutamate to oxaloacetate in the cytosol.

Which reaction is a hydrolysis reaction?

Both the conversion of arginine into urea and ornithine by arginase and the conversion of glutamine into glutamate by glutamase.

Which statement is NOT true of the reaction catalyzed by glutamate dehydrogenase?

It is similar to transamination in that it involves the coenzyme pyridoxal phosphate.

Nitrogen from protein is eliminated as what compound in animals?

Both ammonia and urea.

Deamination of most amino acids in the liver is accompanied by the conversion of:

a-ketoglutarate into glutamate.

Which statement is FALSE regarding ATP synthase?

ADP binds more tightly to the active site than ATP

Which component of the electron-transport chain is NOT an integral membrane protein?

cytochrome c

Which statement about the chemiosmotic theory is correct?

Electron transfer in mitochondria is accompanied by an asymmetric release of protons on one side of the inner mitochondrial membrane.

The electron-transport chain and ATP synthase are effectively coupled. Which statement BEST describes how this occurs?

The electron-transport chain generates an electrochemical gradient that provides energy for the production of ATP.

Which of the following is a mechanism used by the body to transport amine groups to the liver for urea production

Alanine formed by muscle tissue

Which of the following is a mechanism used by the body to transport amine groups to the liver for urea production

Glutamine formed by brain tissue

Conversion of ammonia to carbamoyl phosphate in mitochondria consumes how many ATP equivalents?

two

Which compound is NOT transported across the inner mitochondrial membrane as part of either the urea cycle and aspartate-argininosuccinate shunt?

fumarate

During oxidative phosphorylation, the proton-motive force that is generated by electron transfer is used to:

induce a conformational change in the ATP synthase.

Cyanide, oligomycin, and 2,4-dinitrophenol (DNP) are inhibitors of mitochondrial aerobicphosphorylation. Which statement correctly describes the mode of action of the three inhibitors?

Cyanide inhibits the respiratory chain, whereas oligomycin and DNP inhibit the synthesis of ATP.

Which of the following electron carriers is NOT able to transfer one electron at a time?

NADH

In the process of the urea cycle, during oxidative deamination, why would the enzyme GluDH be sequestered to the mitochondria?

GluDH is responsible for the release of NH4+, which is toxic to cells

Which amino acids are used to transport nitrogen to the liver?

Both alanine and glutamine.

ATP is moved from the mitochondria to the cytosol by ADP/ATP translocase. Which answer choice best characterizes this molecule?

It's an antiporter that moves ADP into the mitochondria while moving ATP out.

Which statement is false regarding flavoproteins?

They are always integral membrane proteins.

Which statement explains why the [ATP]/[ADP][Pi] ratio is relatively stable in a cell?

ATP consumption is balanced by ATP synthase activity.

Glutamate is metabolically converted to a-ketoglutarate and NH4+ by a process described as:

Oxidative deamination.

What is a product of the reaction involving the superoxide free radical catalyzed by superoxide dismutase?

Hydrogen peroxide.

Which amino acid can be considered to be both glucogenic and ketogenic?

Both threonine and isoleucine.

What processes are associated with the glucose-alanine cycle?

All of the answers are correct.

Where does urea synthesis primarily take place in mammals?

Liver.

What is the coenzyme involved in a transaminase reaction?

Pyridoxal phosphate.