Structures and pathways Flashcards
Draw glycolysis completely, all products, substrates, enzymes, GAPDH reaction (only this one) and the additional things in the reaction.
Refer to notes.
Draw all the CAC, with inputs of water, NADH, FADH2, etc.
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Draw the PDC mechanism.
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Draw B-oxidation.
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Draw the Aspartate-malate shuttle.
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Draw the generation of ketone bodies.
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Draw the urea cycle.
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Draw the pathway, from b-hydroxybutyrate for how the body uses ketone bodies.
Refer to notes.
Draw the glucose alanine cycle.
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Draw the urea cycle.
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Draw alanine catabolism.
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Draw Aspargine catabolism
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Draw glutamine catabolism
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Draw Branched chain a-keto acid DH complex pathway.
Refer to notes (same as PDC tbh)
Draw the PPP
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Describe ammonia toxicity.
Two reasons this can happen:
1 - Can get this if the urea cycle is not working properly or
2 - inhale/ingest some form of ammonia.
Ammonia is soluble in the blood and can reach the brain.
Brain tries to get rid of ammonia.
A-keto (common scavenger), takes ammonia and is converted to glutamate by glutamate DH.
Glutamate functions as a NT so it needs to get rid of it and, it cant go in the blood, converted to glutamine using glutamine synthase.
Glutamine is placed in the blood and sent to the liver.
However, this is where the toxicity occurs:
- take lots of a-keto from CAC, gets blocked, not lots of ATP generation in brain
Also, since glutmate is a NT, can create havock, too much is a problem and too little is a problem
- without glutamate, can faint
What are therapies for defects in the urea cycle?
1 - Defined diet with only essential amount of amino acids
2 - Benzoate or phenylacetate - react with glycine and glutamine (respectively) and get excreted in the urine - causes these to be low in body so ammonia levels go down due to synthesis
Which amino acids are branched chain?
Draw R.
Valine (1-3 bis), leucine (2,1,3), isoleucine (1,2,3)
What is a glucogenic amino acid?
Glucogenic aa - catabolized to produce something like pyruvate, oxaloacetate, succinyl-CoA, which can be converted to glucose by neoglucogenesis.
What is a ketogenic amino acids?
Amino acids that make acetyl-CoA when catabolized, converted to ketone bodies.
Describe alkaptonuria.
What process is defective?
What enzyme is defective?
What are the symptoms?
Process: Tyrosine degradation
Enzyme: homogentisate-1,2-dioxygenase
Symptoms: excrete homogentisate
Describe phenylketouria.
What process is defective?
What enzyme is defective?
What are the symptoms?
Process: Conversion of phenylalanine to tyrosine
Enzyme: phenylalanine hydroxylase
Symptom: Excrete Phenylalanine
Describe maple syrup urine disease. What process is defective? What enzyme is defective? What are the symptoms? Treatment?
Process/enzyme: Branched chain keto-acid DHC is defective
Symptoms: brain issues, muscle fatigue, urine smells like maple syrup, branched-chain keto acids accumulate in urine
Treatment: carbs and fats as major dietary source, only small amount of protein for growth
- remove branched chain amino acids from diet
Describe MMA. What process is defective? What enzyme is defective? What are the symptoms? Treatment?
Process: Odd-chain fatty acid catabolism (convert propionyl-A- succinyl-CoA)
Enzyme: Methyl-malonyl-Coa mutase
Symptoms: accumulation of methyl-malonyl-CoA
- fatal, vomiting convulsions, etc.
Treatment: reduce protein intake, remove isoleucine and leucine (branched chain aa) and odd chain fatty acids.
Draw odd-chain fatty acid catabolism
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Draw the cori cycle.
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Why does insulin increase glycolysis?
Indicates there is lots of glucose circulating in the body, makes glycogen first but the rest is converted to acetyl-CoA to be stored as fat.
Describe alcohol toxicity.
When drinking, two enzymes used to catabolized alcohol:
Alcohol DH
Aldehyde DH
Get acetate production.
Both produce NADH, this blocks PDC, CAC and the GAPDH reaction and B-oxidation.
Thus, get accumulation of fat in liver –> hyperlipidemia.
CAC blocked leads to decrease in oxaloacetate and thus inhibition of gluconeogenesis –> hypoglycemia
Excess NADH accelerates lactate DH to produce lactic acid leading to hyperlactiacidemia.
Accumulation of lactic acid and acetic acid from circulating ketone bodies causes liver acidosis.
Describe the effect of leptin on food intake and energy expenditure.
Fat cells produce leptin after fat deposition
Leptin goes into blood to hypothalamus and:
1 - Leads to blocking of synthesis of neuropeptide Y.
2 - Through NT signal via sympathetic neurons, communicates from pituitary to fat tissues
- sends norepinephrine, binds to B3-adrenergic receptor, leads to PKA activation. PKA phosphorylates TF, transcribes UCP - thermogenin
- UCP goes to mt when FA catabolized and leads to generation of heat
