Amino Acid Oxidation & the Urea Cycle (Biochemistry)

Question 1

What many amino acids are hydrophobic?

Answer 1

9

Question 2

How many hydrophillic amino acids are there?

Answer 2

6

Question 3

What are the charged amino acids that are acidic (negatively charged)

Answer 3

• Aspartic acid
• Glutamic acid

Question 4

What are the charged amino acids that are basic (positively charged)

Answer 4

• Lysine
• Arginine
• Histidine

Question 5

What is Autophagy?

Answer 5

Cells break down their own components

Question 6

Why does Autophagy occur?

Answer 6

• Shortage of nutrients
• Break down worn out organelles

Question 7

What occurs to dietary amino acids that exceed body’s protein syntehsis?

Answer 7

They are degraded

Question 8

Where does protein degradation happen?

Answer 8

In the gastrointestinal track

Question 9

What is the function of pepsin?

Answer 9

Cutting protein into peptides in the stomach

Question 10

Where does Trypsin and chymotrypsin cut proteins or large peptides?

Answer 10

Small intestine

Question 11

What does aminopeptidase and carboxypeptidase A and B does to peptide in the small intestine

Answer 11

Degrade peptide into amino acids

Question 12

What is the transportation pathway for amino acids?

Answer 12

Intestinal epithelium -> Blood -> Liver

Question 13

What aare the issues with amino group metabolism?

Answer 13

Produce ammonium (NH4+) which is toxic

Question 14

What removes alpha amino acids in Enzymatic transamination?

Answer 14

Aminotransferases

Question 15

What does all aminotransferases require?

Answer 15

Pyridoxal phosphate cofactor

Question 16

What is L-Glutamate function in Enzymatic Transamination?

Answer 16

Act as a temporary storage of nitrogen

Question 17

What alpha - ketoglutarate accepts amino groups with?

Answer 17

L-glutamate

Question 18

What is Glutamine?

Answer 18

Non toxic transport form of ammonia

Question 19

What is released when Glutamine enters liver mitochondrias?

Answer 19

Ammonium ion

Question 20

What is the Glucose-Alanine Cycle?

Answer 20

Excess nitrogen in extrahepatic tissues travels to the liver as amino acids

Question 21

How is pyruvate coverted to alanine?

Answer 21

Recieving an amino group from glutamate

Question 22

In pyruvate what is ammonium group replaced by?

Answer 22

Oxygen

Question 23

What happens in Glutamate Dehydrogenase Reaction?

Answer 23

Two-electron oxidation of glutamate followed by hydrolysis

Question 24

What is the net process of glutamate?

Answer 24

Oxidative deamination

Question 25

Where does Glutamate Dehydrogenase Reaction occur?

Answer 25

In the mitochondrial matrix

Question 26

What can be used as an electron acceptor in Glutamate Dehydrogenase Reaction?

Answer 26

NAD+ or NADP+

Question 27

What do aquatic vertebrates release into the environment?

Answer 27

Ammonia

Question 28

What are the methods of ammonia release into the environment by aquatic vertebrates?

Answer 28

- Passive diffusion from epithelial cells - Active transport via gills

Question 29

What does terrestrial vertebrates and sharks excrete?

Answer 29

Urea

Question 30

What does birds and reptiles excrete?

Answer 30

Uric acid

Question 31

What are the upsides to urea?

Answer 31

- Less toxic than ammona - Very soluble

Question 32

What are the upsids to uric acid?

Answer 32

- Insouble - Excretion as paste allows to conserve water

Question 33

What are ammonotelic anaimals?

Answer 33

Most aquatic vertebrates (e.g bony fishes)

Question 34

What are ureotelic animals?

Answer 34

Terrestrial vertebrates and sharks

Question 35

What are uricotelic animals?

Answer 35

Birds and reptiles

Question 36

What is the purpose of synthesis of carbamoyl phosphate?

Answer 36

Recapturing ammonia

Question 37

What is the 1st step of the urea cycle?

Answer 37

Carbamoyl phosphate donates carbamoyl group to Ornithine

Question 38

What is the second 2nd step of the urea cycle?

Answer 38

Entry of Aspartate into the urea cycle - Requires ATP and move through an intermediate step

Question 39

What is the second nitrogen acquiring reaction catalysed by?

Answer 39

Argininosuccinate synthetase

Question 40

What is step 3 in urea cycle?

Answer 40

Argininosuccinate is cleaved releasing fumarate & arginine

Question 41

What is the enzyme in step 3 of the urea cycle?

Answer 41

Argininosuccinase

Question 42

What is the side reaction in step 3 of the urea cycle?

Answer 42

Can enter mitochodnria to join the pool of citric cycle intermediates

Question 43

Arginine is cleaved to release urea and Ornithine. What stage of the urea cycle is this?

Answer 43

Step 4

Question 44

What is the catalystic in stage 4 of the urea cycle

Answer 44

Arginase

Question 45

How is the Urea Cycle regulated?

Answer 45

- Protein rich diet - Starvation

Question 46

What is the long term to urea cycle regulation?

Answer 46

Regulation of the 4 urea cycle enzymes and carbamoyl synthetse I in the liver (Higher synthesis rates in starving animals)

Question 47

What is the short term regulation to urea cycle?

Answer 47

Activationr egulation of carbamoyl synthetase I via N-acetylglutamate synthase

Question 48

What links the urea and citric acid cycle?

Answer 48

Arginosuccinate Shunt

Question 49

How much does Arginosuccinate Shunt save?

Answer 49

3 ATP

Question 50

What are the amino acids that are used in Acetyl-CoA?

Answer 50

Leu (Leucine), Ile (Isoleucine), Thr (Threonine), Lys (Lysine), Phe (Phenylalanine), Trp(Tryptophan), Tyr (Tyrosine)

Question 51

What are the amino acids used in pyrvuate?

Answer 51

Ala (Alanine), Thr (Threonine), Trp(Tryptophan), Cys (Cysteine), Gly (Glyine), Ser (Serine),

Question 52

What is the amino acids used in succinyl-CoA?

Answer 52

Met (Methionine) Val (Valine) Ile (Isoleucine), Thr (Threonine),

Question 53

What are the amino acids used in alpha-ketoglutarate

Answer 53

Arg (Arginine) Glu (Glutamic acid) Gln (Glutamine) His (Histidine) Pro (Proline)

Question 54

What are the two amino acids used in fumarate?

Answer 54

(Phe) Phenylalanine (Tyr) Tyrosine

Question 55

What molecules are ketogenic?

Answer 55

- Acetoacetyl-CoA - Acetyl-CoA

Question 56

What molecules are Glucogenic?

Answer 56

- Pyruvate - OXaloacetate - Fumarate - Succinyl-CoA - Alpha-Ketoglutarate

Question 57

What amino acids are exclusively ketogenic?

Answer 57

Lecuine, Lysine

Question 58

What molecule is exclusively Glucogenic?

Answer 58

Arginine,

Question 59

What amino acid is both ketogenic and glucogenic?

Answer 59

Phenylalanine, Tryptophan, Isoleucine, TYrosine