Amino Acid Oxidation & Urea Cycle

Question 1

T/F the use of amino acids as fuel varies greatly by organism

Answer 1

True !

Question 2

Describe how dietary protein is enzymatically degraded

Answer 2

1. GASTRIN hormone released
   - causes Parietal to release HCL
   - causes chief cells to release : PEPSINOGEN
   - pepsinogen converted into PEPSIN
2. Low PH triggers SECRETION HORMONE
   - secretion hormone stimulates pancreas to release bicarbonate
3. CHOLECYSTOKININ secretes
   - trypsinogen
   - chymotrpsin
   - procarboxypeptidase
4. ENTEROPEPTIDASE converts trypsinogen to trypsin

trypsin converts zymogens to active form:

• trypsinogen —> trypsin
• chymotrypsinogen —> chymotrypsin
• procarboxypeptidase A & B –> Carboxy Peptidase A & B

Question 3

What do parietal cells release

Answer 3

HCL

Question 4

what do chief cells release

Answer 4

Pepsinogen

Question 5

low PH in the small intestines trigger release of what hormone

Answer 5

secretion

Question 6

secretion hormone triggers release of what from the pancreas

Answer 6

bicarbonate

Question 7

what converts trypsinogen to trypsin? and once trpysin is formed what happens

Answer 7

enteropeptidase converts trypsinogen to trypsin. trypsin converts zymogens to their active form

Question 8

what is occuring in acute pancreatitis

Answer 8

zymogens are getting converted into their active form . Clearly the pancreatic trypsin inhibitor is not working because it should protect the pancreas from getting affected by a protease

Question 9

what 3 zymogens are present in the pancreas

Answer 9

trypsinogen
chymotrypsinogen
procarboxypeptidase

Question 10

the less toxic form of ammonia is called

Answer 10

urea

Question 11

Breifly describe what happens to an amino acid when it gets broken down

Answer 11

the NH4 goes thru the urea cycle and the the carbon skeleton goes through the citric acid cycle and can eventually go thru gluconeogeneisis.

Question 12

what does ammonotelic mean

Answer 12

secrete ammonia

Question 13

what does ureotellic mean

Answer 13

secrete urea

Question 14

what does uricotellic mean

Answer 14

secretes urea and ammonia

Question 15

amino groups form many amino acids are collected in the form of ______ in the liver

Answer 15

glutamate

Question 16

where does oxidative deamination occur

Answer 16

in the mitochondrial matrix of the liver

Question 17

what enzyme is needed for oxidative deamination

Answer 17

glutamate dehydrogenase

Question 18

what are the negative and postive regulators of glutamate dehydrogenase?

Answer 18

• is GTP

+ is ADP

Question 19

Where does the urea cycle occur

Answer 19

it occurs in 2 compartments of the liver cell.

• Liver mitochondria
• Cytosol

Question 20

where does the feeder step of the urea cycle occur

Answer 20

in the mitochondrial matrix

Question 21

what is the rate limiting step of the urea cycle

Answer 21

the feeder step

Question 22

what are 4 important enzymes for the urea cycle

Answer 22

ornithine transcarboxylase
arniginosuccinate sythase
arginosuccinase
arginase

Question 23

what does the krebs bicycle refer to

Answer 23

pathway linking the urea cycle with the citric acid cycle

Question 24

what is the name of the feeder enzyme for the urea cycle

Answer 24

cabamoyl phosphate synthase 1

Question 25

under what kind of conditions would we see a highly active urea cycle

Answer 25

high protein diet, starvation when protein being broken down for energy

Question 26

what is a positive regualator of cabormyl phosphate synthase 1

Answer 26

n acetylglutamate

Question 27

what are the 2 fates of a carbon skeleton

Answer 27

ketogenic amino acids or glucogenic amino acids

Question 28

what do ketogenic amino acids yield

Answer 28

convert to ketone bodies, yield acetyl coa

Question 29

carbomyl phosphate synthetase 1 disorder will cause

Answer 29

+ ammonia

Question 30

ornithine transcarbamylase disorder will cause

Answer 30

+ ornithine, + uracil, + orotic acid

Question 31

arginosucuccinic acid synthetase disorder will cause

Answer 31

+ citruline

Question 32

arginosuccinase acid lyase disorder will cause

Answer 32

+ citruline , + arginosuccinc acid

Question 33

arginase disorder will cause

Answer 33

+ argine

Question 34

pernicious anemia is caused by

Answer 34

B12 deficiency , folic acid deficiency , premature erythrocytes

Question 35

What 2 tissues are important for diagnosis of heart and liver damage caused by heart attack ?

Answer 35

ALT GPT, AST, GOT

Question 36

Why are urea disorders dangerous

Answer 36

nitrogen accumulates in the form of ammonia which is a highly toxic substance if not removed from the body

Question 37

a urea cycle disorder is an example of what kind of disorder

Answer 37

inborn error of metabolism

Question 38

what 2 aromatic amino acids are given to help with urea disorders

Answer 38

the aromatic amino acids benzoate and phenulbutyrate are given which combine with glycine and glutamine and are excreted in urine . ammonia is used to replenish the loss of these amino acids

Question 39

2 examples of ammonia scavenging medications are

Answer 39

bezoate and phenylacetate

Question 40

PKU is caused by lack of

Answer 40

phenylanine hydroxylase

Question 41

Tyrosinemia II is caused by lack of

Answer 41

tryrosine aminotransferase

Question 42

Tyrosenemia III is caused by lack of

Answer 42

p hydroxyphenylpyruvated dioxygenase

Question 43

alkaptonuria is caused by lack of

Answer 43

homogentisate 1,2, dioxygenase

Question 44

tyrosenemia is caused by lack of

Answer 44

fumarylacetoacetase

Question 45

a build up of phenylalanine and phenylpyruvate can lead to what kind of symptoms

Answer 45

intellectual deficits

Question 46

how is PKU controlled

Answer 46

limiting dietary intake of Phe

Question 47

T/F degradation of branched chain amino acids occurs in the liver

Answer 47

false ! it does not occur in the liver. it happens in muscle, adipose tissue, muscle , kidney and brain

Question 48

what enzyme is defective in maple syrup urine disease

Answer 48

branched chain a keto acid dehydrogenase complex