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Tough ones Flashcards

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1
Q

Where does Q get it’s ammonium from?

A

NH4

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2
Q

What is the role of ALT in starvation?

A

Takes pyruvate generated in muscles and converts it to alanine for transport to the liver

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3
Q

N (when produced from Q) gets it NH4 from where?

A

From Q

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4
Q

What is the enzyme that catalyzes the reaction of glycine to serine?

A

Serine-hydroxymethyl transferase

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5
Q

What is the most oxidized form of THF?

A

N10

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6
Q

What is the most reduced form of THF?

A

N5

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7
Q

What are the molecule that donate to the one carbon pool?

A

Formaldehyde, formate, S, G, H

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8
Q

What is the cause and symptoms of Homocystieneuria?

A

Defect in Cystathinoine beta synthase

Lens dislocation, MR, thromboembolism

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9
Q

What are the symptoms of PKU? Treatment?

A

MR, SZs, rash

Low F and Y diet

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10
Q

Which amino acids serve as carbon donors in the blood?

A

A and Q

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11
Q

HHF6 lowers the activity of what other enzyme? What is this involved in?

A

N-acetyl glutaminase, which lower the N-acetyl Q production an the urea cycle.

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12
Q

A defect in the glycine cleavage system will result in what condition?

A

Glycine encephalopathy

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13
Q

Biotin is needed for what reaction?

A

Propionyl-coa to d-methylmalonyl-coa via propionyl coa decarboxylase

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14
Q

There are only two reactions in the body that require B12. Which are they?

A

Propionyl to succinyl-coa reaction

Homocystine to methionine reaction

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15
Q

The ONLY reaction in the body that can oxidize N5-methyl THF is what reaction? What variant of THF is produced in the process?

A

THF

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16
Q

What is the chemical responsible for he discoloration of alkaptonuria?

A

Benzoquinone

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17
Q

Tyrosenemia I is the result of a defect in fumarylacetoacetate hydrolase. What is produced INSTEAD of fumarate and acetate?

A

Succinyl acetone

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18
Q

Which amino acids can undergo deamination without an aminotransferase?

A

THCS

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19
Q

In the intestinal renal axis, what amino acid is picked up? What is it then converted to?

A

Q, then citrulline, then R

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20
Q

There are two compounds given to someone with urea cycle issues. Name them, and the amino acids they reaction with.

A

Phenyl-butryrate reactions with glutamine

Benzoate reacts with glycine

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21
Q

Name the enzyme that produces GABA from E, and Histamine from H

A

Pryidoxal phosphate

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22
Q

FA oxidation/ketone synthesis increases transcription for related enzymes through what system?

A

PPRE

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23
Q

Gluconeogenesis stimulate transription of enzymes through what?

A

CRE

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24
Q

Insulin induces transcription of lipid synthesis enzymes via what?

A

SRE

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25
Insulin represses transcription of gluconeogenesis enzymes via what?
IRE
26
The enzyme IDO converts what to what in which pathway?
W to N-formylynurine in the synthesis of niacin
27
How does the enzyme IDO contribute to cancer?
Excess activity leads to the blocking of T cell action on cancer cells
28
A defect in carbomoyl synthetase I leads to what condition?
Hyperammonemia
29
A defect in Ornathine transcarbamoylase leads to what condition?
Hyperammonemia
30
A defect in arginosuccinate synthetase leads to what condition?
Citrullinemia
31
A defect in Arginosuccinate lyase leads to what condition?
Arginosuccinate acid uria
32
A defect in Arginase leads to what condition?
Hyperarginemia
33
What enzyme catalyzes the transfer of Glutathione to chemicals for breakdown?
Glutathione s-transferases
34
What are three symptoms common to DM patients?
Fasting hypoglycemia Hyperlipidemia Gluconeogenesis from muscles
35
Why is there hyperlipidemia in DM patients?
Insulin is either ineffective at inhibiting HSL or not present.
36
What are the two main transcription changes brought about by insulin?
Increases in FA synthetase | Decrease in PEP carboxykinase
37
AIP is the result of a defect in what enzyme? What are the symptoms?
Defect in PBG deamidase. Acute abdominal pain, dark red urine, and neuro symptoms
38
PCT is the result of a defect in which enzyme? Symptoms?
UPG III decarboxylase. | Photosensitivity, pink urine
39
What enzymes in the heme cycle does Pb inhibit?
ALA synthase and Ferrochelatase
40
What gives urine and stool their characteristic color?
Urobilin
41
How will PREhepatic jaundice present in regards to bilirubin in the serum, urine, and stool?
Elevated unconjugated bili in blood | No change in urine or stool
42
How will HEPATIC jaundice present in regards to bilirubin in the serum, urine, and stool?
Increase is unconjugated bili in the blood | Lower amount of bili in urine and stool
43
How will POSThepatic jaundice present in regards to bilirubin in the serum, urine, and stool?
Increase in conjugated bili in the blood Stool bili lower Urine bili way higher
44
PRPP is synthesized from what substrate and via which enzyme?
RIbose-5-phosphate | PRPP synthase
45
What is the enzyme that comitted PRPP to purine synthesis? What is the product?
Amidoribosyltransferase | PRA
46
What are the four components that the purine de-novo synthesis pathway require?
Amino acids (GED) CO2 N10 formyl THF ATP
47
What is required for AMP synthesis? For GMP?
GTP and ATP respectively.
48
AMP and GMP are phosphorylated by what enzymes?
nucleotide mono(di)phosphate kinases
49
PRPP synthetase in inhibited by what?
ADP and GDP
50
What are the inhibitors and activators of Amidoribosyl transferase?
``` Inhibitors = GMP, AMP, Activator = PRPP ```
51
Why does EtOH consumption worsen symptoms of gout?
Liver damage = increased ATP turnover, lactic acid production competes with uric acid for excretion
52
What is the treatment for gout? What does the chemical used get metabolized into?
Allopurinol | Oxypurinol
53
Ortic acid uria is the result of a defect in what enzyme?
UMP synthase
54
UMP synthase is a combination of which two enzymes?
Oratate phosphoribosyl transferase and OMP decarboxylase
55
CAD is a combination of which three enzymes?
Carbamoyl phophate sythetase Aspartate transcarbamoylase Dihydroorotase
56
Megaloblastic anemia that responds to Folate and B12 is the result of what? If these do not produce a response, then what is responsible?
B12 deficiency (acts on Homocysteine to methionine rxn and THF generation--no purines) Ortic acid uria if not responsive (no pyrimidine synthesis due to UMP synthase defect).
57
Hydroxyurea blocks which reaction?
Ribonucleotide reductase
58
Deoxyribonucleotides are producted via which enzyme?
Ribonucleotide reductase
59
Ribonucleotide reductase requires what molecule to reduce ribonucleotide?
Thioredoxin
60
Thioredoxin is reduced back from it oxidative state via which enzyme? Which electron donor molecule does this require?
Thioredoxin reductase. | NADPH
61
Which dNTP regulates all dNTP production
dATP
62
How is CTP generated?
From UTP via CTP synthase
63
SCID is a defect in what enzyme?
Adenosine deamiase
64
A defect in adenosine deaminase results in the accumulation of adenosine in the degradation of AMP. What disease does this result in?
SCID
65
True or false: CMP, TMP, UMP are all phosphorylated by mono(di)ribonucletoide phosphate kinases to produced CTP, TTP and UTP.
FALSE TMP, TDP, and TTP do no exist in the body--only dTMP
66
5-fluorouracil is converted into what, then what, and inhibits what?
FUMP, FdUMP, and irreversibly binds Thymidylate synthase
67
Beta-alanine is produced from what?
Degradation of the pyrimidines UMP, CMP, and dCMP
68
Betaisobutryate is produced from what?
Degradation of the pyrimidine dTMP | used as a measure of DNA turnover
69
Purine bases (guanine, hypoxanthine, and adenine) are converted to their nucleosides by which enzymes?
Hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) Adenine phosphoribosyltransferase (APRTase)
70
APRTase is inhibited by what?
Inhibited by AMT
71
HGPRTase is inhibited by what?
Inhibited by GMP, IMP
72
There is only one purine NUCLEOTIDE that can be taken up. Which is it?
Adenosine by adenosine kinase
73
Which pyrimidine BASE cannot be taken up by humans?
Cytosine
74
Lesch-Nyhan syndrome is the result of a defect in what enzyme? Symptoms?
HGPRTase | Symptoms - hyperuriemia, MR, chewing off of fingers
75
Free pyrimidines (not cytosine) are taken up by which enzyme?
Pyrimidine phosphoribosyltransferase
76
What enzyme in fungi allows for the use of 5-fluorocytosine as a antifungal medication?
Cytosine deaminase
77
Methotrexate is an inhibitor of what enzyme? How does this affect DNA synthesis?
Inhibits dihydrofolate reductase, part of the thymidylate synthase reaction. Thus dTMP cannot be produced.
78
Carbamoyl phosphate synthase II is regulated by what?
Activated by PRPP | Inhibited by UMP
79
CTP synthase is regulated by what?
Activated by UTP | Inhibited by CTP
80
Where does CTP synthase get amine group from?
Q to E reaction
81
PRPP synthase is regulated by what?
Inhibited by GDP and ADP
82
Amidoribosyltransferase is inhibited by what?
GMP and AMP

Enzymes (24 decks)

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