Amino Acid Metabolism

Question 1

Sources of Amino Acids

Answer 1

Body protein degradation, dietary proteins, Synthesis of non-essential amino acids

Question 2

Products of Amino Acids

Answer 2

Porphyrin, Creatine, Hormones, Neurotransmitters, Purine, Pyrimidines, Niacin, and Thyroxine

Question 3

AA Synthesis (up to Citric Acid Cycle)

Answer 3

1. Glucose
2. Fructose 1,6-bisphosphate
3. 3-Phosphoglycerate
4. Pyruvate
5. Acetyl-CoA

Question 4

Citric Acid/Krebb’s Cycle

Answer 4

1. Acetyl-CoA
2. Citrate
3. Isocitrate
4. Alpha Ketoglutarate
5. Succinyl-CoA
6. Fumarate
7. Oxaloacetate

Question 5

AA synthesis (definition )

Answer 5

Precursors of the 20 amino acids found in humans are obtained from carbohydrate metabolism (glycolysis and Citric Acid Cycle)

Question 6

AA Degradation

Answer 6

Proteins broken down into AA and metabolized via carbohydrate metabolic pathways (glycolysis and citric acid cycle); breakdown of AAs helps the body regulate nitrogen levels and excrete excess via urea

Question 7

Transamination

Answer 7

Add amine group (ex. alpha ketoglutarate to glutamate)

Question 8

Deamination

Answer 8

Removal of amine group (glutamate to alpha ketoglutarate)

Question 9

Urea Cycle (definition)

Answer 9

series of enzyme reactions in liver cell mitochondria and cytoplasm (organelles involved)

Question 10

Why is Urea Cycle Important?

Answer 10

Removes excess nitrogen and toxic by-product ammonia via the production of urea; helps maintain the body’s nitrogen balance

Question 11

What is involved in the start of the Urea Cycle?

Answer 11

Carbon Dioxide and Ammonia (from glutamate)

Question 12

How is Carbamoyl Phosphate formed in the Urea Cycle?

Answer 12

Created from Carbon dioxide combining with ammonia in the presence of the enzyme carbamoyl phosphate synthase

Question 13

How is Citrulline formed in the Urea Cycle?

Answer 13

Product of Carbomoyl Phosphate breakdown from the enzyme Orinithine Transcarbamoylase

Question 14

How is Urea, the final product of the Urea Cycle, formed?

Answer 14

Formed in the cytosol with the start of citrulline crossing the wall of the mitochondria; Citrulline - Arginosuccinate - Arginine - Urea (enzymes: arginosuccinate synthase, arginosuccinase, and Arginase)

Question 15

Examples of Interconversion (which maintains Buffering System)

Answer 15

Alpha ketoglutarate to/from glutamate to/from glutamine offers the body an important system to utilize, generate and/or store ammonia

Question 16

Interconversion of Glutamate (from alpha-ketoglutarate)

Answer 16

Add ammonia

Question 17

Interconversion of Glutamine (from glutamate)

Answer 17

Add ammonia

Question 18

Interconversion of Glutamate (from Glutamine)

Answer 18

Remove ammonia

Question 19

Interconversion of Alpha-Ketoglutarate (from Glutamate)

Answer 19

Remove ammonia