Nitrogen 2 Flashcards
Removal of nitrogen happens mainly in the ______ and only ______ can lose its nitrogen by transamination.
liver, glutamate
What are the fates of nitrogen in plants, aquatic animals, terrestrial/sharks, birds/reptiles and humans?
Conserve almost all Release ammonium Excrete through urea Excrete uric acid Excrete both urea and uric acid
What happens if uric acid crystallises in the joins?
Causes inflammation
Ammonia is transported through the bloodstream as ______ and excess is processed in the ______, ______ and ______.
Glutamine, intestines, kidney, liver
Glutamine donates ammonia to pyruvate to make what?
Alanine
Why are alanine/glutamine used in the glucose-alanine cycle?
They have a neutral charge so can pass through membranes easily.
Where is excess glutamate metabolised?
In the mitochondria of hepatocytes.
Describe step 1 of glutamate dehydrogenase.
Glutamate - 2 electron oxidation -> intermediate
- hydrolysis -> alpha-ketoglutarate
Describe step 2 of glutamate dehydrogenase.
Ammonia is recaptured via synthesis of carbamoyl phosphate
What enzyme is present in step 2 of glutamate dehydrogenase?
Carbamoyl phosphate synthase.
Describe step 3 of glutamate dehydrogenase.
Nitrogen from carbamoyl phosphate enters urea cycle as aspartate.
After removal of amino groups, what happens to carbon skeletons?
Converted to glucose or oxidised in the citric acid cycle.
What are the 8 essential amino acids?
Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine
Give the citric acid cycle starting from the addition of Acetyl CoA to oxaloacetate.
(Acetyl CoA) -> Oxaloacetate -> citrate -> Isocitrate -> alpha-ketoglutarate -> succinyl CoA -> Succinate -> fumarate -> malate -> (Acetyl CoA)
