Final W4

Question 1

Dietary amino acids are transported through the __ __ to the liver. Within ___ amino groups from most amino acids are transferred to _____ to form ____. This is then transported into the ___ and releases ___.

Answer 1

circulatory system, hepatocytes, alphaketoglutarate, glutamate, mitochondria, NH4+

Question 2

____ is a chemical reaction that transfers an amino group to a ___ __ to form a new amino acid. _____ is the amino group acceptor, while the _____ is the amino acid donor. This is catalyzed by an ____. These reactions function to collect amino groups from many different amino acids in the form of ____.

Answer 2

transamination, keto acid, alpha-ketoglutarate, L-amino acid, aminotransferase, L-glutamate

Question 3

All aminotransferases use ___ ____ as a prosthetic group. PLP is derived from ____ (vitamin B6), and functions as an amino group carrier. ___ ___ is the aminated form and ___ and amino group. PLP is the __ form and ___ the amino group

Answer 3

pyridoxal phosphate, pyridoxine, pyridoxamine phosphate, donates, aldehyde, accepts

Question 4

Some extrahepatic tissues generate ___, which is toxic and metabolized to ___ using ATP for transport to the liver. Within liver ___, NH4+ and glutamate are released, regenerating glutamate

Answer 4

NH4+, glutamine, mitochondria

Question 5

catalyzes the release of glutamate and NH4+ through hydrolysis

Answer 5

glutaminase

Question 6

Vigorously contracting skeletal muscle (____), produces large amounts of _____ through glycolysis and _____ through protein catabolism. The pyruvate can be metabolized to ___ through transamination, then this product is transported to the liver where transamination again produces ___ and ___.

Answer 6

anaerobic, pyruvate, NH4+, alanine, glutamate, pyruvate

Question 7

in the muscle, ___ ___ catalyzes transfers NH4+ from glutamate to ___ forming alanine and _____. The alanine is transported to the liver via the ___, where __ ___ catalyzes the transfer of NH4+ from alanine to _____ reforming pyruvate and ___. All generate glutamate within liver mitochondria

Answer 7

alanine aminotransferase, pyruvate, alpha-ketoglutarate, blood, alanine aminotransferase, pyruvate, glutamate

Question 8

Amino groups from many different ____ acids are collected as the amino group of ____, which is transported into the mitochondria. ___ ___ catalyzed by ___ ____ produces free NH4+ and alpha-ketoglutarate

Answer 8

alpha-amino, L-glutamate, oxidative deamination, L-glutamate dehydrogenase

Question 9

enzymatic transfer of an amino group from an alpha amino acid to an alpha keto acid

Answer 9

transamination

Question 10

enzymatic removal of an amino group from an alpha amino acid, generating an alpha keto acid and NH4+

Answer 10

oxidative deamination

Question 11

transamination and oxidative deamination

Answer 11

transdeamination

Question 12

Aminotransferases are used to detect ___ ___ following infection, excessive alcohol consumption or __ ___. ___ and ____ aminotransferases are in much higher concentration in those with liver damage

Answer 12

liver damage, drug toxicity, alanine, aspartate

Question 13

a metabolic pathway in the vertebrate liver that synthesizes urea from amino groups and CO2

Answer 13

urea cycle

Question 14

Urea contains one amino group derived from __ __ and one derived from ___

Answer 14

carbamoyl phosphate, aspartate

Question 15

___ ___ ___ ___ catalyzes the formation of carbamoyl phosphate from ___, __ and ____.

Answer 15

carbamoyl phosphate synthetase I, NH4+, HCO3, ATP

Question 16

____ _____ catalyzes the formation of ___ from glutamate and ____

Answer 16

aspartate aminotransferase, aspartate, oxaloacetate

Question 17

The formation of carbomoyl phosphate requires two ___ steps. First bicarbonate is ___ to form ____ ___. Then nucleophilic attack by ___ displaces the phosphate, generating ____. Phosphorylation of this product forms __ ___

Answer 17

activation, phosphorylated, carbonic-phosphoric anhydride, NH3, carbamate, carbomoyl phosphate

Question 18

In the first step of the urea cycle, ___ __ catalyzes the formation of ____ from carbomoyl phosphate and ornithine. The carbomoyl group has high ___ potential.

Answer 18

ornithine transcarbamoylase, citrulline, transfer

Question 19

In step two of the urea cycle, __ ___ catalyzes the formation of ___ from citrulline and _____. This occurs via a ____ reaction between the amino group of aspartate and ___ group of citrulline. It proceeds through a ______ intermediate

Answer 19

arninosuccinate synthetase, arginosuccinate, aspartate, condensation, carboxyl, citrullyl-AMP

Question 20

In step 3 of the urea cycle, _______ catalyzes cleavage of arginosuccinate forming ___ and ___. The latter is metabolized to ___ and transported to the __ ___ to enter the citric acid cycle

Answer 20

arginosuccinase, arginine, fumarate, malate, mitochondrial matrix

Question 21

In step 4 of the urea cycle, ___ catalyzes cleavage of arginine releasing __ and regenerating __

Answer 21

arginase, urea, ornithine

Question 22

The urea cycle requires ___ ATP equivalents. Oxidizing malate to ___ within the citric acid cycle generates ____, which can generate ____ ATP by oxidative phosphorylation each. Interconnections between pathways reduces the __ ___

Answer 22

4, oxaloacetate, NADH, 2.5, energetic cost

Question 23

___ ___ are transported into the mitochondrial matrix as malate. Malate is then metabolized to __ and returned to the cytosol

Answer 23

reducing equivalents, aspartate

Question 24

Argininosuccinase deficiency can be treated by providing a surplus of __ in the diet while also restricting total protein ___. This results in ___ of argininosuccinate, which replaces __

Answer 24

arginine, intake, excretion, urea

Question 25

Ornithine transcarbamoylase deficiency can be treated by protein ___ diet and large amounts of __ and ___. The excess nitrogen accumulates as ____ and _____. Benzoate is metabolized to __ which is excreted, and phenylacetate is metabolized to _____ which is also excreted

Answer 25

restricted, benzoate, phenylacetate, glycine, glutamine, hippurate, phenylacetylglutamine,