Q 7: Protein Metabolism: Oxidation & Urea - German

Question 1

What are the four fates of dietary amino acids?

Answer 1

Protein synthesis

Energy production (Citric Acid Cycle)

Biosynthesis

Urea Excretion

Question 2

What are the three drivers of protein oxidation?

Answer 2

Normal synthesis and degradation

Protein rich diet

Starvation or diabetes mellitus

Question 3

Why are proteins broken down if they’re not immediately used?

Answer 3

There is no way to store amino acids/proteins

Question 4

What is an enzyme precursor that requires a biochemical change for activation (usually cleavage)?

Answer 4

Zymogen

Question 5

What are the pancreatic zymogens?

Answer 5

Trypsinogen —> trypsin

Chymotrysinogen —> chymotrypsin

Procarboxypeptidase A and B —> carboxypeptidase A and B

Question 6

What does trypsin do?

Answer 6

It cleaves chymotrypsinogen into chymotrypsin

Question 7

What are the fates of amino acids?

Answer 7

Used for protein and biosynthesis within cells

Catabolized for energy within cells

Transported to the liver and excreted

Question 8

What does dietary protein lead to (referring to the cascade of hormones)?

Answer 8

Dietary protein —> gastrin secretion —> HCl release —> pH drop

Dietary protein —> gastrin secretion —> pepsinogen —> pepsin, secretin, and cholecystokinin release

Question 9

What does pepsin do?

Answer 9

.

Question 10

What does secretin do?

Answer 10

.

Question 11

What does cholecystokinin do?

Answer 11

.

Question 12

Where does most amino acid catabolism take place?

Answer 12

Liver

Question 13

What are the metabolically important amino acids?

Answer 13

Glutamate

Aspartame

Glutamine

Alanine

(Amine group carriers, precursors and common metabolites, and entry and exit molecules from the citric acid cycle)

Question 14

Ammonia is toxic to all animals except?

Answer 14

Aquatic animals/fish? They secrete ammonia

Question 15

What are symptoms of ammonia buildup in mammals?

Answer 15

.

Question 16

NH4+ does what in the brain?

Answer 16

Disrupts astrocyte K+ uptake

Question 17

What happens when you get high extracellular K+ in the brain?

Answer 17

GABA inhibition is prevented

Leads to neuronal hyperactivity, seizures, oxidative stress, death

Question 18

How have animals developed to prevent NH4+ problems in the brain?

Answer 18

The body keeps NH4+ levels in the blood relatively low.

Vertebrates create stable molecules of UREA to avoid NH4+ probs

Birds turn it into uric acid

Question 19

What are transaminase reactions?

Answer 19

They move amine groups from one ketoacid to another (the new amino acids often become amine carriers)

Question 20

What happens when you add an amine group to glutamate?

Answer 20

You get glutamine

Question 21

What makes glutamine a common synthetic precursor?

Answer 21

Its ability to transport NH4+

Question 22

What allows proteins to function as energy sources?

Answer 22

Glucose-alanine cycle (G-A cycle)

(It will use pyruvate from glycolysis and turn it into alanine which is shuttled to the liver and used in gluconeogenesis to generate glucose)

Question 23

What amino acids feed into fumarate in the CAC?

Answer 23

Phenylalanine

Tyrosine

Question 24

What is a glucogenic amino acid?

Answer 24

Amino acid that can be converted to glucose

Question 25

What is a ketogenic amino acid?

Answer 25

Amino acid that can be converted to ketone bodies (broken down into acetyl-CoA)

Question 26

Which amino acid can become pyruvate or succinyl-CoA?

Answer 26

Threonine

Question 27

What AA are broken down into pyruvate?

Answer 27

Alanine

Cysteine

Glycine

Serine

Threonine

Tryptophan

Question 28

What AA are broken down into oxaloacetate?

Answer 28

Asparagine

Aspartate

Question 29

What AA’s are both glucogenic and ketogenic?

Answer 29

Threonine, isoleucine, tryptophan, phyenylalanine, tyrosine

Question 30

Which AA is a one-step reaction to a-ketoglutarate?

Answer 30

Glutamate!!!!!

Question 31

What AA’s become succinyl-CoA?

How much energy does this produce (least, middle, most)?

Answer 31

Methionine

Isoleucine

Valine

Threonine

(Middle-low ish)

Question 32

What are the AA’s that become a-ketoglutarate?

How much energy does this produce (least, middle, most)?

Answer 32

Glutamate

Glutamine

Proline

Arginine

Histidine

(Middle ish)

Question 33

What are the AA’s that become Acetyl-CoA?

How much energy does this produce (least, middle, most)?

Answer 33

Tryptophan

Lysine

Phenylalanine

Tyrosine

Leucine

Isoleucine

Threonine

(Most energy from AA’s)