3 Amino Acids & Nitrogen Metabolism

Question 1

What structures are found in the interstitial space of the Intestinal Epithelium, which are critical for the absorption of nutrients to the body?

Answer 1

Blood Vessels

Question 2

By what method do proteins obtain passage across the epithelium of the digestive tract to the blood stream?

Answer 2

By hydrolysis to Amino Acid monomers

Question 3

Once entered in to the blood stream, what is the main use in the body for amino acids?

Answer 3

Protein Building

Question 4

Which elements found in Amino Acids?

Answer 4

C, H, O, N

Question 5

With regard to constituent elements, how are Amino Acids different to other macromolecules such as carbohydrates or lipids?

Answer 5

Nitrogen

Question 6

What are the nitrogen-free intermediates formed from Amino Acids?

Answer 6

Glucose

Ketone Bodies

(And CO₂ + H₂O)

Question 7

Why is Urea formed in the body?

Answer 7

Ammonia is toxic to humans

Question 8

What is the toxic nitrogenous substance which can be formed from catabolism of Amino Acids?

Answer 8

Ammonia

NH₃

Question 9

Which metabolic intermediate can Amino Acids form in order to synthesise Fatty Acids and Lipids?

Answer 9

Acetyl CoA

Question 10

What other functions do Amino Acids play apart from fuel metabolism and construction material for proteins?

Answer 10

Precursor Molecules

Effector Molecules

Question 11

What type of stored fuel constitutes the second largest energy store in the body?

Answer 11

Protein

Question 12

Which component of an Amino Acid determines the structure and function of proteins?

Answer 12

R-Group

(Side Chain)

Question 13

Where is Ammonia synthesised in the body?

Answer 13

Anywhere in the body

Question 14

What is the site of urea formation in the body?

Answer 14

The Liver

Question 15

What are the three methods for removal of Amino Groups from amino acids?

Answer 15

Transamination

Oxidative Deamination

Non-Oxidative Deamination

Question 16

Which of the following is the major pathway for removal of ammonia from the body?

Transamination

Oxidative Deamination

Non-Oxidative Deamination

Answer 16

Transamination

Question 17

Which Coenzyme is present in all transamination reactions?

Answer 17

Pyridoxal Phosphate

Question 18

Pyridoxal phosphate, the active form of vitamin B6, is a coenzyme in what type of reaction?

Answer 18

Transamination

Question 19

Which three molecules are the main transporters for Ammonia to the liver?

Answer 19

Glutamate

Glutamine

α-Ketoglutarate

Question 20

What is the function of the below biomolecules?

Glutamate

Glutamine

α-Ketoglutarate

Answer 20

Transport of Ammonia (NH₃) to the liver

Question 21

Glutamine is found in high concentrations in healthy blood, what is the purpose of this substance?

Answer 21

Transport of Ammonia (NH₃) to the Liver

Question 22

How many NH₃ groups can one Glutamine molecule transport?

Answer 22

Two

Question 23

Transition between α-Ketoglutarate ⇔ Glutamate is mediated by what enzyme?

Answer 23

Glutamate Dehydrogenase

Question 24

Transition from Glutamate to Glutamine is mediated by what enzyme?

Answer 24

Glutamine synthase

Question 25

Unloading Glutamine of ammonia is initiated by which enzyme?

Answer 25

Glutaminase

Question 26

Which of the following enzymes mediates a reversible reaction: Glutamate Dehydrogenase Glutamate Synthetase Glutaminase

Answer 26

Glutamate Dehydrogenase

Question 27

Which of the following enzymic reactions requires **ATP**? Glutamate Dehydrogenase Glutamine Synthetase Glutaminase

Answer 27

Glutamine Synthetase

Question 28

In which of the following enzymic reactions is **NAD⁺ converted to NADH**? Glutamate Dehydrogenase Glutamine Synthetase Glutaminase

Answer 28

Glutamate Dehydrogenase

Question 29

In which reaction is **Flavin Mononucleotide (FMN)** used as an electron acceptor?

Answer 29

Oxidative Deamination

Question 30

**Flavin Mononucleotide** (FMN) uses **which enzyme** to free ammonia from amino acids?

Answer 30

L-amino acid oxidase

Question 31

What **cofactor** is used by **L-amino acid oxidase** during **Oxidative deamination**?

Answer 31

FMN

Question 32

What is H₂O₂?

Answer 32

Hydrogen Peroxide

Question 33

Is **Hydrogen Peroxide** (H₂O₂) produced during **Oxidative Deamination**, or **Non-Oxidative Deamination**?

Answer 33

Oxidative Demaination

Question 34

Which of the following is **Ammonium**? NH₃ NH₄

Answer 34

NH₄

Question 35

Where does the **Urea Cycle** take place?

Answer 35

Mitochondria *and* Cytosol

Question 36

In molecular terms, what is the main **CO₂ carrier** of the bloodstream?

Answer 36

Bicarbonate

Question 37

What is the product of the **protonation** of **Ammonia**?

Answer 37

Ammonium NH₄⁺

Question 38

What molecule is the starting and end point of the **Urea Cycle**?

Answer 38

Ornithine

Question 39

Which set of reactions is **Ornithine** the starting point for?

Answer 39

The Urea Cycle

Question 40

Reactions involving **Ornithine** occur in which part of the cell?

Answer 40

Mitochondria

Question 41

Carbamoyl Phosphate reacts with which molecule in the Urea Cycle to form Citruline?

Answer 41

Ornithine

Question 42

What is the product of the reaction of **Ornithine** and **Carbamoyl Phosphate** in the mitochondria?

Answer 42

Citrulline

Question 43

what is the end result of ß-Oxidation of uneven-numbered chains of fatty acids?

Answer 43

Proprionyl-CoA

Question 44

**Proprionyl-CoA** is the result of **ß-Oxidation** of fatty acid chains with **even** or **uneven** numbers of carbons?

Answer 44

Uneven

Question 45

Which amino acid is also an excitatory neurotransmitter?

Answer 45

Aspartate