Biochemistry - Pulmonary / Renal Block (III) Flashcards
Amino acids whose citric acid cycle intermediates can be subsequently converted to ____________ are termed glucogenic as they are easily entered into gluconeogenesis.
Amino acids whose citric acid cycle intermediates can be subsequently converted to ____________ are termed ketogenic as they are easily entered into fatty acid or ketone synthesis.
Amino acids whose citric acid cycle intermediates can be subsequently converted to ____________ are termed both glucogenic and ketogenic as they are easily entered into both of the above pathways.
Oxaloacetate;
acetyl-CoA;
pyruvate
Amino acids whose citric acid cycle intermediates can be subsequently converted to pyruvate are termed ___________.
Amino acids whose citric acid cycle intermediates can be subsequently converted to oxaloacetate are termed ___________.
Amino acids whose citric acid cycle intermediates can be subsequently converted to acetyl-CoA are termed ___________.
Both ketogenic and glucogenic;
glucogenic;
ketogenic
Which are the amino acids that are solely ketogenic (2)?
What does this mean?
Leucine, lysine;
they are easily converted to acetyl-CoA
Which are the amino acids that are solely glucogenic (9)?
What does this mean?
Arginine
Asparagine & Glutamine
Aspartate & Glutamate
Histidine
Methionine
Proline
Valine;
they are easily converted to oxaloacetate
Which are the amino acids that are either ketogenic or glucogenic (9)?
What does this mean?
Alanine
Cysteine
Glycine
Isoleucine
Phenylalanine
Serine
Threonine
Tryptophan
Tyrosine;
they are readily converted to pyruvate (which is easily convertible to acetyl-CoA and oxaloacetate)
Decide (for each AA individually) if each of the following amino acids is ketogenic, glucogenic, or both:
Proline
Tryptophan
Serine
Valine
Methionine
Glucogenic
Both
Both
Glucogenic
Glucogenic
Decide (for each AA individually) if each of the following amino acids is ketogenic, glucogenic, or both:
Threonine
Histidine
Lysine
Isoleucine
Glutamine
Both
Glucogenic
Ketogenic
Both
Glucogenic
Decide (for each AA individually) if each of the following amino acids is ketogenic, glucogenic, or both:
Glutamate
Aspartate
Phenylalanine
Asparagine
Aspartate
Glucogenic
Glucogenic
Both
Glucogenic
Glucogenic
Decide (for each AA individually) if each of the following amino acids is ketogenic, glucogenic, or both:
Arginine
Cysteine
Leucine
Tyrosine
Glycine
Glucogenic
Both
Ketogenic
Both
Both
Any amino acid that can be converted to (1) _________ is termed both glucogenic and ketogenic because (1) can be converted both to (2) _________ and (3) _________.
(Note: not all AA that are both glucogenic and ketogenic can be converted to (1). Some can enter the citric acid cycle at multiple intermediates.)
(1) Pyruvate,
(2) acetyl-CoA, (3) oxaloacetate
What are the (1) buildup product(s) and (2) deficient enzyme of homocystinuria?
Homocysteine (and possibly methionine);
cystathione β-synthase
What are the (1) buildup product(s) and (2) deficient enzyme of maple syrup urine disease?
Branched-chain ketoaciduria;
branched-chain α-ketoacid dehydrogenase complex
What are the (1) buildup product(s) and (2) deficient enzyme of methylmalonic acidemia?
L-Methylmalonic acid (and possibly propionyl-CoA);
methylmalonyl-CoA mutase
What are the (1) buildup product(s) and (2) deficient enzyme of phenylketonuria?
Phenylalanine;
phenylalanine hydroxylase
What are the (1) buildup product(s) and (2) deficient enzyme of alkaptonuria?
Homogentisate;
homogentisate oxidase
What are the (1) buildup product(s) and (2) deficient enzyme of type I tyrosinemia?
Fumarylacetoacetate;
fumarylacetoacetate hydrolase
What are the (1) buildup product(s) and (2) deficient enzyme of type II tyrosinemia?
Tyrosine;
tyrosine aminotransferase
What inborn error of metabolism is associated with a buildup of homocysteine (and possibly methionine)?
What enzyme is deficient?
Homocystinuria;
cystathione β-synthase
What inborn error of metabolism is associated with a buildup of branched-chain α-ketoacids?
What enzyme is deficient?
Maple syrup urine disease;
branched-chain α-ketoacid dehydrogenase complex
What inborn error of metabolism is associated with a buildup of L-methylmalonic acid?
What enzyme is deficient?
Methylmalonic acidemia;
methylmalonyl-CoA mutase
What inborn error of metabolism is associated with a buildup of phenylalanine?
What enzyme is deficient?
Phenylketonuria;
phenylalanine hydroxylase
What inborn error of metabolism is associated with a buildup of homogentisate?
What enzyme is deficient?
Alkaptonuria;
homogentisate oxidase
What inborn error of metabolism is associated with a buildup of fumarylacetoacetate?
What enzyme is deficient?
Type I tyrosinemia;
fumarylacetoacetate hydrolase
What inborn error of metabolism is associated with a buildup of tyrosine?
What enzyme is deficient?
Type II tyrosinemia;
tyrosine aminotransferase
Phenylketonuria is basically an inability to convert ____________ to ___________.
Why does this affect neurotransmitter production?
Phenylalanine, tyrosine;
tyrosine is a precursor for catecholamine synthesis
Asides from a phenylalanine hydroxylase deficiency (the most common cause), what other issues might cause phenylketonuria?
(1) A deficiency of tetrahydrobiopterin (BH4) (a cofactor for phenylalanine hydroxylase and catecholamine synthesis);
(2) an inability to regenerate BH4 from BH2 (via dihydropteridine reductase)
A 45-year-old male presents with complaints of worsening arthralgias. Upon further studies, you note that his urine turns brown when left exposed to air.
What is at the top of your differential?
What deficiency is responsible?
Alkaptonuria;
the enzyme homogentisate oxidase
How is maple syrup urine disease managed?
Via restriction of branched-chain amino acids
(valine, isoleucine, leucine)
What substrate may build up in cases of severe B12 deficiency, causing acidemia?
This is because a certain enzyme involving acids requires B12 as a cofactor. Which is it?
This is an alternate cause of what type of acidemia?
L-Methylmalonic acid;
methylmalonyl-CoA mutase;
methylmalonic acidemia
What are the two major methyl donors in the body?
S-Adenosylmethionine;
folate (and its derivatives)
What two vitamins are needed for S-adenosylmethionine (SAM) (a methyl donor) regeneration?
After donating its methyl group, SAM becomes S-adenosylhomocysteine, then homocysteine, then methionine.
In which part of this chain are the two vitamins necessary?
B12 and folate;
the conversion of homocysteine to methionine
After donating its methyl group, S-adenosylmethionine (SAM) becomes S-adenosylhomocysteine, then homocysteine.
What are the two products that are typically now produced from homocysteine?
Which vitamins are required for each path?
Either: (1) methionine (to regenerate SAM), B12 and folate;
or (2) cystathione, B6 (pyridoxal phosphate)
Methylmalonyl-CoA can be created from the metabolism of propionyl-CoA. It is then often converted to _____________ to enter the citric acid cycle.
What enzyme and vitamin are involved in this conversion?
Succinyl-CoA;
methylmalonyl-CoA mutase, B12
A deficiency of which of the following can cause an elevation in blood homocysteine: vitamin B12, vitamin B6, or folate?
A deficiency of which of the following can cause an elevation in blood L-methylmalonic acid: vitamin B12, vitamin B6, or folate?
All three;
B12 only
What acid often builds up in addition to L-methylmalonic acid?
Propionic acid
If poorly controlled, which of the following inborn errors of metabolism are most likely to cause intellectual disability and other neurological disabilties?
Alkaptonuria
Type I tyrosinemia
Type II tyrosinemia
Phenylketonuria
Homocystinuria
Maple syrup urine disease
Methylmalonic acidemia
Type II tyrosinemia
Phenylketonuria
Homocystinuria
Maple syrup urine disease
Methylmalonic acidemia
How does type I tyrosinemia often present?
A cabbage-like odor in the urine;
liver failure, renal tubular acidosis
Which are the *conditionally essential amino acids (6)?
(*E.g. essential during growth, pregnancy, illness, etc.)
Arginine
Cysteine
Glutamine
Glycine
Proline
Tyrosine
Which are the nonessential amino acids (5)?
Alanine
Asparagine
Aspartate
Glutamate
Serine
State if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Alanine
Nonessential;
both;
pyruvate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Arginine
Conditionally essential;
glucogenic;
α-ketoglutarate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Asparagine
Nonessential;
glucogenic;
oxaloacetate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Aspartate
Nonessential;
glucogenic;
oxaloacetate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Cysteine
Conditionally essential
both;
pyruvate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Glutamine
Conditionally essential;
glucogenic;
α-ketoglutarate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Glutamate
Nonessential;
glucogenic;
α-ketoglutarate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Glycine
Conditionally essential;
both;
pyruvate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Histidine
Essential;
glucogenic;
α-ketoglutarate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Isoleucine
Essential;
both;
succinyl-CoA, acetyl-CoA
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Leucine
Essential;
ketogenic;
acetyl-CoA, acetoacetate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Lysine
Essential;
ketogenic;
acetoacetate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Methionine
Essential;
glucogenic;
succinyl-CoA
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Phenylalanine
Essential;
both;
fumarate, acetoacetate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Proline
Conditionally essential;
glucogenic;
α-ketoglutarate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Serine
Nonessential
both;
pyruvate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Threonine
Essential;
both;
succinyl-CoA. acetyl-CoA
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Tryptophan
Essential;
both;
pyruvate, acetoacetate, acetyl-CoA
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Tyrosine
Conditionally essential;
both;
fumarate, acetoacetate
First, state if the following amino acid is essential, conditionally essential, or nonessential.
Second, state if the following amino acid is glucogenic, ketogenic, or both.
Third, name the citric acid cycle intermediate(s) into which it is readily convertible.
Valine
Essential;
glucogenic;
succinyl-CoA
What enzyme can convert aspartate and α-ketoglutarate to oxaloacetate and glutamate?
What enzyme can interconvert glutamate and α-ketoglutarate?
Aspartate aminotransferase (AST);
glutamate dehydrogenase
What enzyme can convert glutamate to glutamine?
What enzyme can convert glutamine to glutamate?
Glutamine synthetase;
glutaminase
What enzyme can interconvert alanine and pyruvate?
What enzyme can interconvert aspartate and oxaloacetate?
Alanine aminotransferase (ALT);
aspartate aminotransferase (AST)
What enzyme can convert aspartate to asparagine?
What enzyme can convert asparagine to aspartate?
Asparagine synthetase;
asparaginase
In the Cahill cycle, what molecule travels from the muscle to the liver to boost gluconeogenesis?
In the Cori cycle, what molecule travels from the muscle to the liver boost gluconeogenesis?
Alanine;
lactate
The Cahill cycle increases liver gluconeogenesis in times of ____________.
The Cori cycle increases liver gluconeogenesis in times of ____________.
Starvation;
hypoxia
Epinephrine, norepinephrine, and dopamine are synthesized from what common precursor?
Tyrosine
Starting with tyrosine, what is the order of intermediates and products in catecholamine synthesis?
Tyrosine –>
DOPA –> Dopamine –> Norepinephrine –> Epinephrine
GABA is made from what immediate precursor?
Histamine is made from what immediate precursor?
Serotonin is made from what precursors?
Glutamate;
histidine;
tryptophan, then 5-HT
Which neurotransmitters require pyridoxal phosphate (B6 derivative) for their synthesis?
Dopamine (from DOPA);
GABA (from glutamate);
histamine (from histidine);
serotonin (from 5-HT)
What cofactors are needed for the synthesis of DOPA from tyrosine?
What cofactors are needed for the synthesis of epinephrine from norepinephrine?
What cofactors are needed for the synthesis of norepinephrine from dopamine?
Tetrahydrobiopterin (BH4; aka Kuvan);
vitamin C and copper (Cu2+);
vitamin B12, folate, S-adenosylmethionine
Why are Parkinsons patients treated with both L-DOPA and carbidopa?
(Hint: L-DOPA stimulates dopamine production in both the CNS and PNS.)
Carbidopa inhibits PNS dopamine production, limiting the L-DOPA-driven increase in dopamine production to just the CNS
What are porphyrias?
Rare disorders of heme synthesis
Which is the most common porphryia?
Cutanea tarda
Which porphryia does not cause a sensitivity to light?
Acute intermittent porphyria
Which porphyrias are hepatic?
Cutanea tarda (both erythropoeitic and hepatic);
acute intermittent;
hereditary coproporphyria;
variegate
Which substrate sometimes produced in porphyrias can produced skin photosensitivity?
Uroporphyinogen I
Which porphyrias are erythropoeitic?
Cutanea tarda (both erythropoeitic and hepatic);
congenital erythropoeitic;
erythpoeitic protoporphyria
Name the enzyme defect and buildup product for the following porphyria:
Acute intermittent porphyria
Hydroxymethylbilane synthetase;
porphobilinogen & δ-ALA
Name the enzyme defect and buildup product for the following porphyria:
Congenital erythropoeitic porphyria
Uroporphyrinogen III synthase;
uroporphyrinogen I & coproporphyrinogen I
Name the enzyme defect and buildup product for the following porphyria:
Cutanea tarda porphyria
Uroporphyrinogen decarboxylase;
uroporphyrin
Name the enzyme defect and buildup product for the following porphyria:
Hereditary coproporphyria
Coproporphyrinogen oxidase;
coproporphyrinogen III
Name the enzyme defect and buildup product for the following porphyria:
Variegate porphyria
Protoporphyrinogen oxidase;
protoporphyrinogen IX
Name the enzyme defect and buildup product for the following porphyria:
Erythropoeitic protoporphyria
Ferrochetalase;
protoporphyrin
What is the rate-limiting step of heme synthesis?
ALA synthase forms δ-ALA
Which steps of heme synthesis are inhibited by lead poisoning?
(Which enzymes are involved?)
The 2nd step and the final step
(ALA dehydratase & ferrochetalase)
Describe the functions of the spleen and the liver in bilirubin metabolism.
1. Splenic macrophages destroy senescent erythrocytes, releasing bilirubin
2. Unconjugated bilirubin is carried to the liver by albumin
3. The liver conjugates the bilirubin with glucuronic acid
After the spleen destroys senescent RBCs, bilirubin forms, and the liver conjugates that bilirubin with ________________,
what happens next (as far as elimination of the bilirubin from the body)?
Glucuronic acid;
1. The conjugated bilirubin is secreted into the duodenem in bile
2. The intestinal flora deconjugates the bilirubin and converts it to urobilinogen
3. This urobilinogen either remains in the gut and is secreted in feces as stercobilin or reabsorbed and secreted in the urine as urobilin
The liver enzyme ___________ ___________ conjugates bilirubin with __________ __________ to form __________ __________ (conjugated bilirubin).
Bilirubin glucuronyltransferase;
glucuronic acid;
bilirubin diglucuronide
What form of bilirubin is most elevated in the blood in cases of hemolytic jaundice?
Unconjugated
What form of bilirubin is most elevated in the blood in cases of obstructive jaundice?
Bilirubin diglucuronide (conjugated bilirubin)
What form of bilirubin is most elevated in the blood in cases of hepatocellular jaundice?
Both unconjugated bilirubin and conjugated (bilirubin diglucuronide)
Why do some newborns develop neonatal jaundice?
Is this a problem?
Their hepatic bilirubin glucuronyltransferase (the conjugating enzyme) is not yet fully functional;
yes, it can cause kernicterus (neonatal jaundice-induced encephalopathy)
Why is unconjugated bilirubin called indirect bilirubin?
Why is conjugated bilirubin called direct bilirubin?
It does not react as easily with reagent and is determined by ‘total bilirubin - direct bilirubin;’
it reacts easily with reagent and is directly measured
__________ __________ is an energy carrier in the muscle formed by the phosphorylation of __________.
Both of the above molecules can cyclize to form __________, which is quickly secreted by the kidneys.
Creatine phosphate, creatine;
creatinine
Decreased levels of plasma creatinine are indicative of:
Elevated levels of plasma creatinine are indicative of:
Elevated levels of creatine kinase are indicative of:
Muscle atrophy;
kidney dysfunction;
possible myocardial infarction
What enzyme turns muscle creatine into creatine phosphate?
Creatine kinase
A.
A.
D.
A.
E.
E.
A.
A.
B.
D.
