Nitrogen Flashcards
From what nitrogen fixing bacteria do we get out nitrogen?
Diazatrophs
What do diazatrophs have the ability to do?
Take gaseous nitrogen and turn it into molecules containing nitrogen
Can humans breathe in nitrogen?
No
Why do humans need nitrogen?
As it is a vital element for our biochemistry - used for alot of biomolecules
Which amino acids can take nitrogen and interconvert into other amino acids?
Glutamate
Before N2 can be removed from the body what must it be converted back into?
Glutamate
Why is nitrogen so un-reactive?
Due to the triple bonds between the atoms
What do root nodules on legumes contain?
Rhizobium bacteria
What is rhizobium bacteria?
Nitrogen-fixing bacteria
What enzyme does nitrogen fixation require?
Nitrogenase
What is alot of needed in nitrogen fixation?
Energy
What effect does oxygen have on nitrogenase?
It inactivates it
How does nitrogenase live?
Anaerobically
What do leguminous plants produce to keep O2 levels low?
Leghemoglobin
What does leghemoglobin do?
Binds to O2 - keeping the concentration of O2 low enough to allow nitrogenase to work
Put in the correct order nitrogen to (nitrite, nitrate, ammonium)
Nitrogen
Ammonium
Nitrite
Nitrate
Flow of N from NH4+ to toher biomolecules occurs through which amino acid?
Glutamate
What is the keto acid of glutamate?
a-ketoglutarate
Adding NH4+ to a-ketoglutarate converts it to what?
Glutamate
Removing nH4+ form glutamate converts it to what?
a-ketoglutarate
What 4 amino acids are found in much higher concentrations that other a/a?
Alanine
Glutamate
Aspartate
Glutamine
What are amino acids the building blocks for?
Proteins
What is transamination?
The transferring of amino groups between different molecules
When the amino group is taken of an amino acid what does it become?
Keto Acid
In transamination what is often one of the 2 substrate pairs?
Glutamate
Is transamination reversible?
Yes very reversible
What is the only amino acid with the ability to leave the cell?
Glutamate
Which molecules acts as temporary storage of nitrogen?
L-Glutamine
What typically accepts amino groups?
a-ketoglutarate
Which enzymes are needed for transamination reactions?
Aminotransferases
What do aminotransferase enzymes require?
Pyridoxal phosphate
What is pyridoxal phosphate and what is it made from?
Co-factor made from vitamin B6
How is energy yielded from amino acids?
Amino acids are oxidised
They are a significant energy-yielding pathway in carnivores
What enzyme cuts proteins into peptides in the stomach?
Pepsin
What enzymes cute proteins and larger peptides into smaller peptides in the small intestine?
Tyrpsin and chymotrypsin
Where are proteins broken down in the body?
Stomach and small intestine
Why would cellular proteins be broken down?
The protein is misfolded
The protein is foreign
The protein is unwanted
What is the end point of the degradation of cellular proteins?
Individual amino acids
What is an essential amino acid?
One that the body cannot synthesised so must be obtained from our diets
Why is glutamate transported as glutamine?
Because of the charge to get through the membrane
What is the glutamate dehydrogenase reaction?
The two electron oxidation of glutamate
Followed by hydrolysis
How does nitrogen enter the urea cycle?
Nitrgoen from carbamoyl phosphate enters the urea cycle
How is the toxic ammonia quickly recaptured?
Into carbamoyl phosphate
