Nitrogen 2 Flashcards
What is the only way that nitrogen can get in and out of the body?
Through glutamate
How do we excrete nitrogen?
By producing urea (from amino acids) and uric acid (from purines)
What is ammonia transported in the bloodsteam as?
Glutamine, with excess glutamine beingprocessed in the intestines, kidneys and liver
How can pyruvate be converted into alanine?
By glutamate donating an amino group
What does pyruvate being converted into alanine during vigourous exercise prevent?
A build up of lactice acid
Where is the alanine that can be built up during vigorous exercise transported to?
The liver
What is the process of the glucose-alanine cycle?
- Proteins are broken down in exercising if required
- Transported to the liver as alanine
- Resulting carbon skeleton in converted into pyruvate
- Nitrogen exreted as ammonia and converted to urea
- Pyruvate is converted in glucose by gluconeogenesis
Why is glutamine and alanine used for transport and not glutamate?
They have no charge so can pass through membranes much easier
Where is excess glutamate metabolised?
Mitochondria of hypatocytes (liver cells)
What happens to the ammonia once glutamate is broken down in the liver?
Recaptured by the synthesis of carbamoyl phosphate which is the first nitrogen acquiring reaction
What is the first nitrogen acquiring reaction?
Capture of amino gorup from breakdown of glutamate by carbamoyl phosphate
What is the second nitrogen acquiring reaciton?
Entry of asparate into the urea cycle
What does a summary of the entry of intermediates from glycolysis, beta oxidation and the breakdown of amino acids into the citric acid cycle look like?
What are the 6 compounds that the 20 amino acids can enter the citric acid cycle through?
Acetyl coenzyme A
Pyruvate
a-ketoglutamate
Succinyl coenzyme A
Fumarate
Oxaloacetate
What is the main role of carbohydrates and fats?
To provide energy
