Biochemistry Quiz 4: Practice Questions for Nitrogen and amino acid metabolism and Others

All enzyme

catalyzed aminotransferase reactions remove

amino groups from amino acids, producing what byproduct

that is important during metabolic stress?

A.

Pyruvate

B A hydride and a H+

C. One of the ketone body molecules

D.

Fumarate

E. An alpha ketoacid

E. An alpha ketoacid

In amino acid catabolism, the first reaction for many amino acids is

a(n):

A) decarboxylation requiring thiamine pyrophosphate (TPP).

B) hydroxylation requiring NADPH and O2.

C) oxidative deamination requiring NAD+.

D) reduction requiring pyridoxal phosphate (PLP).

E) transamination requiring pyridoxal phosphate (PLP).transamination requiring pyridoxal phosphate (PLP).

E) transamination requiring pyridoxal phosphate (PLP).transamination requiring pyridoxal phosphate (PLP).

The acidic and alkaline environments of the upper

gastrointestinal tract promote what type of enzymes needed to

activate pro pro-enzymes that are required for protein

metabolism?

A.

Aminotransferases

B Mixed

Mixed-function oxidases

C. Peptidases

D.

Dehydrogenases

E.

Hydratases

C. Peptidases

Amino acids are not stored in appreciable concentrations.

However, what amino acid would be found in significant

concentration in blood of basketball players after a long and

intense workout in a gym?

A.

Histadine

B Alanine

C. Glutamine

D.

Cysteine

E.

Proline

B Alanine

Two nitrogen containing groups are used to make urea in liver

cells. What two molecules of the Urea Cycle contribute to

those two groups ?

A.

Carbamoyl phosphate and Asp

B

Ala and Glu

C.

Glu and Gln

D.

Carbamoyl phosphate and Glu

E.

Arg and Asp

A.

Carbamoyl phosphate and Asp

The Urea Cycle itself requires two different cellular

compartments. What other pathway also requires two cellular

compartments?

A. Glycolysis

B Pentose phosphate, oxidative phase

C. Beta

Beta-oxidation

D. Gluconeogenesis

E. Glyoxylate

D. Gluconeogenesis

What molecule that is produced in the cytosol by the Urea

Cycle can be used by the Citric Acid Cycle, but cannot pass

the inner mitochondrial membrane?

A.

Malate

B

Arginosuccinate

C.

Ornithine

D. NAD+

E.

Fumarate

E.

Fumarate

Amino acid oxidation requires cofactors that can serve as a

one carbon source for amino acid and nucleotide synthesis.

Which molecule below does not function as a one carbon

transfer molecule?

A.

Pyridoxal phosphate

B Biotin

C.

S adenosylmethionine

D.

Tetrahydrofolate

E. All of the above are involved in one

carbon

transfers.

A.

Pyridoxal phosphate

Which molecule below is produced by oxidation of most amino

acids, leading to potential carbon loss by organisms that

cannot fix carbon?

A. Methane

B Acetate

C.

Glycine

D. Bicarbonate

E. Carbon dioxide

E. Carbon dioxide

What molecule is produced from oxidation of a number of

amino acids, and which can be used to produce ATP efficiently

via oxidative phosphorylation?

A. NADPH

B Acetate

C. NADH

D. Ammonia

E. FADH2

C. NADH

What is the metabolic use of

Ketogenic amino acids?

A. All are used to produce alpha

alpha-ketoglutarateketoglutaratefor

Kreb's

Cycle.

B All are used to produce ketone bodies.

C. All are used to produce the

keto -forms of

carbohydrates that substitute for glycolytic

intermediates.

D. All are used as one

one-carbon donors for the formation

of alpha

alpha-ketoacidsketoacids.

E. All are used in

Ketogenesis , the formation of

ketone -containing amino acids

B All are used to produce ketone bodies.

Glutamine synthetase converts _____ to _____ whereas glutamate

synthase converts ____ to _____.

A)

formate ; glutamine; ammonia; glutamate

B)

asparagine; glutamine; alpha ketoglutarate; glutamate

C)

alpha ketoglutarate; glutamine; oxaloacetic acid; glutamate

D)

alpha ketoglutarate; glutamine; alpha ketoglutarate; glutamate

E)

glutamate; glutamine; alpha ketoglutarate; glutamate

E)

glutamate; glutamine; alpha ketoglutarate; glutamate

Nonessential amino acids:

A)

are amino acids other than those required for protein synthesis.

B)

are not utilized in mammalian proteins.

C)

are synthesized by plants and bacteria, but not by humans.

D)

can be synthesized in humans as well as in bacteria.

E)

may be substituted with other amino acids in proteins

D)

can be synthesized in humans as well as in bacteria.

An amino acid that does not derive its carbon skeleton, at

least in part, from alpha ketoglutarate is:

A)

arginine.

B)

glutamate.

C)

glutamine.

D)

proline.

E)

threonine.

E)

threonine.

In which group are all the amino acids closely interrelated

metabolically?

A)

Arginine, hydroxyproline , and histidine

B)

Arginine, tyrosine, and glutamate

C)

Glycine, valine, glutamine, and aspartate

D)

Ornithine, alanine, glycine, and valine

E)

Ornithine, proline, arginine, and glutamate

Ornithine, proline, arginine, and glutamate

If a cell were unable to synthesize or obtain

tetrahydrofolic acid

(H4 folate), it would probably be deficient in the biosynthesis of:

A)

isoleucine.

B)

leucine.

C)

lysine.

D)

methionine.

E)

serine.

D)

methionine.

The nitrogen atom in the side chain of lysine is derived from

which amino acid?

A)

Aspartic acid

B)

Glutamic acid

C)

Glutamine

D)

Asparagine

E)

Arginine

B)

Glutamic acid

The amino acid __________ and is an intermediate in the

biosynthesis of _________.

A)

histidine; purines

B)

glycine; heme

C)

serine; heme

D)

serine; sphingosine

E)

glutamine; glutathione

B)

glycine; heme

Bile pigments are:

A)

formed in the degradation of heme .

B)

generated by oxidation of sterols.

C)

responsible for light reception in the vertebrate eye.

D)

secreted from the pancreas

E)

the products of purine degradation.

A)

formed in the degradation of heme .

The hormones epinephrine and norepinephrine are derived

biosynthetically from:

A) arginine.

B) histidine.

C) isoleucine.

D) tryptophan.

E) tyrosine.

E) tyrosine.