Urea Cycle Flashcards
Summarise the Urea cycle
1) Arginine –> Ornithine, Urea Produced
2) Ornithine –> Citrulline w/ NH3 and CO2
3) Citrulline –> Arginine w/ Ammonia
Where does Arginine come from for the UC?
Diet/protein breakdown
What does 1 turn of urea cycle consume?
3 ATP and 4 high energy nucleotides
What may happen if deficient in enzymes involved in urea cycle?
Ammonia levels in blood increase
Danger of ammonia levels in blood too high?
Increased NH3 will cross the blood-brain barrier
Converted to glutamate, so decrease in AKG
Less oxaloacetate, KC stops so cell damage and neural death
Why might increased NH3 levels mean KC stops?
NH3 –> Glutamate, so les oxaloacetate so KC stops
Cell damage and death
What is absorptive state of glucose regulation?
1) Ingested nutrients absorbed from GI tract into blood
2) Some nutrients catabolised and used, remainder stored for future use
What is the post-absorptive state of glucose regulation?
1) Nutrients no longer absorbed from GI tract
2) Nutrient stores must supply energy requirements of the body
What are the major proteins produced by the liver?
Albumin and Clotting Factors
What is Albumin?
Single polypeptide, 9-12g produced by liver each day
Why is Albumin important (4)?
1) Binding and transport
2) Maintenance of colloid osmotic pressure
3) Free Radicals
4) Anticoagulant Effects
What causes Albumin to decrease and consequences of this?
1) Decreased synth, increased catabolism and loss
2) Decreased ligand binding and colloid oncotic pressure
