Chp. 36

Question 1

The most abundant nitrogenous waste excreted by humans; it contains two nitrogen atoms per molecule?

Answer 1

Urea

Question 2

This nitrogenous waste is produced as a byproduct of muscle metabolism?

Answer 2

Creatinine

Question 3

Which amino acid has 4 nitrogen atoms per molecule; 3 of which form a guanidino group?

Answer 3

Arginine

Question 4

This clinical blood test is used to assess kidney function?

Answer 4

The BUN (blood urea nitrogen)

Question 5

This nitrogenous waste is a byproduct of purine base metabolism?

Answer 5

Uric Acid

Question 6

This B vitamin is required as a coenzyme of transaminases?

Answer 6

B6

Pyridoxal phosphate

Question 7

When an amino group is removed from an amino acid by a transaminase, it transfers this amino group to what acceptor substrate?

Answer 7

An a-keto acid

aKG or OAA

Question 8

This aminotransferase is abbreviated as AST?

Answer 8

Aspartate transaminase

Question 9

This aminotransferase is abbreviated as ALT?

Answer 9

Alanine transaminase

Question 10

The carbon skeleton of alanine is deaminated by ALT to yield this 3 carbon group used by the Kreb’s cycle?

Answer 10

Pyruvate

Question 11

Cellular location of most oxidative de-aminations?

Answer 11

The mitochondria

Question 12

The deamination of glutamine by glutaminase yield this amino acid plus NH4+

Answer 12

Glutamic acid/ glutamate

Question 13

The deamination of asparagine by asparaginase yield this amino acid plus NH4+

Answer 13

Aspartic acid/aspartate

Question 14

In the brain, this amino acid’s deamination supplies nitrogens for purine synthesis?

Answer 14

Aspartate

Also glutamine does too!

Question 15

This tissue uses glutaminase to produce NH4+ which is excreted along with metabolic acids?

Answer 15

The Kidneys

Question 16

This first enzyme of urea synthesis uses bicarb, NH4+ and ATP as substrates?

Answer 16

Carbamoyl phosphate synthetase I

CPSI

Question 17

This unique amino acid is used in the urea cycle to react with carbamoyl phosphate to form citrulline?

Answer 17

Ornithine

Question 18

In this third reaction of the urea cycle, citrulline is reacted with aspartate to form this

Answer 18

Arginosuccinate

Question 19

This enzyme cleaves arginosuccinate to yield fumarate and arginine

Answer 19

Arginosuccinate lyase

Question 20

In the urea cycle, this enzyme releases formed urea?

Answer 20

Arginase

Question 21

When the liver fails to package ammonia as urea this occurs in the blood?

Answer 21

Hyperammonemia

Question 22

This 3 letter abbreviation (BUN) is used to indicate what?

Answer 22

Blood Urea Nitrogen

Question 23

What is the effect of hyperammonemia on the CNS?

Answer 23

Portal-systemic Encephalopathy

Question 24

During Fasting, Alanine is de-aminated and the amine group transferred to this molecule by ALT?

Answer 24

Alpha-ketoglutarate

Question 25

In the cytosolic reactions of the Urea Cycle, the only nitrogen in aspartate ends up in this molecule after arginosuccinate synthetase and lyase

Answer 25

Arginine

Question 26

To create new Ornithine to carry out the urea cycle, this unique molecule is transaminated by an amino group from glutamate?

Answer 26

Glutamate semialdehyde