Urea Cycle

Question 1

Where does MOST of the urea cycle occur?

Answer 1

cytosol

Question 2

Is the urea cycle occurring in the well fed or starved state?

Answer 2

NONE

Question 3

What are the important amino acids in the urea cycle?

Answer 3

Arginine and Glutamate

Question 4

What is the main amino acid produced by the urea cycle?

Answer 4

Arginine

Question 5

Where does the urea cycle start?

Answer 5

Mitochondria (stage 1 & 2)

Question 6

What is the ratio of citrinin and ornithine

Answer 6

1:1

Question 7

Where is he highest amount of N+ found?

Answer 7

proteins

Question 8

What is ALT?

Answer 8

Alanine Aminotransferase

Question 9

What is AST?

Answer 9

Aspartate Aminotransferase

Question 10

ALT transfers and converts what 4 ketacids?

Answer 10

turn Alanine and Pyruvate to a-ketogluterate and Glutamate

Question 11

Liver Health Blood Test detects what?

Answer 11

levels of ALT and AST

Question 12

What is the purpose of ALT and AST?

Answer 12

the ability of the liver to process amino acids to ketoacids

Question 13

AST transfers and converts what 4 ketoacids?

Answer 13

turn asparate and oxeloacetate to a-ketogluterate and glutamate

Question 14

What is the process of disposing amino acids?

Answer 14

same as synthesis but reversed

• bring in a-amino acid and convert it to an a-ketoacid
• bring in a-ketoglutarate to glutamate
• NADP to NADPH + NH3

Question 15

What is the process of synthesizing amino acids?

Answer 15

same as disposing but reversed

• bring in a a-ketoacid and convert to an a-amino acid
• bring in a glutamate and turn it into a-ketogluterate
• NADPH + NH3 to NADP

Question 16

How many ATP go into the urea cycle?

Answer 16

3 ATP?

Question 17

How does the ATP breakdown to when leaving the urea cycle?

Answer 17

2ADP + AMP + 2Pi +PPi

Question 18

What does glutamate reacts with ATP + NH4?

Answer 18

ADP + Pi products

becomes Glutamine

Question 19

Which molecules, when combined with Nitrogen, can freely transfer through the system?

Answer 19

Glutamine

Question 20

Which molecule, when not combined with Nitrogen, stays in the liver?

Answer 20

Glutamate

Question 21

Which enzyme puts a nitrogen on glutamate?

Answer 21

glutamine synthetase

Question 22

Which enzyme lyses nitrogen off of glutamine

Answer 22

glutaminase

Question 23

Does fumarate go to malate during the well fed or starved state?

Answer 23

NONE

Question 24

What allows fumarate to become malate?

Answer 24

Fumarase enzyme 
substrate H20 (Krebs cycle reaction)

Question 25

What happens to fumarate during the well-fed state?

Answer 25

fumarate becomes malate

utilize it by taking it inside the mitochondrial matrix to make energy

Question 26

During the fasting state. what happens to fumarate?

Answer 26

Fumarate turns into malate
Malate turns into Oxaloacetate
Oxaloacetate enters gluconeogenesis

Question 27

Which disease involves a defective conversion of Phe to Tyr?

Answer 27

Phenylketonuria

Question 28

What gives people with Phenylketonuria a musty odor to their urine?

Answer 28

phenylalanine accumulates and is converted to compounds such as phenylketones

Question 29

What sources would generate nitrogen byproducts?

3

Answer 29

Purines And Pyrimidines
Muscles
Glutamine

Question 30

Which disease causes degenerative arthritis because homogentisic acid auto-oxidizes and forms dark colored pigments which accumulate in various tissues?

Answer 30

Alcaptonuria

Question 31

Which disease is caused by a decrease in dopamine due to a deficiency in conversion of Dopa?

Answer 31

Parkinson’s Disease

Question 32

Which disease involves deffective tyronsinase and Tyr cannot be converted to skin pigment melanin?

Answer 32

Albinism