Nitrogen 1 Flashcards
<p>What is nitrogen metabolism also known as?</p>
<p>Amino acid metabolism</p>
<p>What kinds of molecules contain nitrogen?</p>
<p>Amino acids and nucleotides</p>
<p>Where do we get our nitrogen from?</p>
<p>Our diet, not the air</p>
<p>What are the 2 stages of the nitrogen cycle in organmisms?</p>
<p>Assimilation</p>
<p>Degradation</p>
<p>Why is nitrogen very unreactive?</p>
<p>Nitrogen is bonded to another nitrogen with a triple bond</p>
<p>What are 3 things that supply the massive amound of energy required to breakdown nitrogen?</p>
<p>Lighting</p>
<p>450oC at 200atp with an iron catalyst</p>
<p>Bacteria</p>
<p>What does bacteria perform to breakdown nitrogen?</p>
<p>Nitrogen fixation</p>
What does nitrogen fixation look like?
any natural or industrial process that causes free nitrogen
<p>What is nitrogen inactivated by?</p>
<p>O2</p>
<p>How does bacteria get around O2deactivating N2?</p>
<p>Live anaerobically</p>
<p>Uncouple mitochondria to burn all O2in a cell</p>
What does the process of nitrogen after it is fixed look like?
Fixation converts nitrogen in the atmosphere into forms that plants can absorb through their root systems. A small amount of nitrogen can be fixed when lightning provides the energy needed for N2 to react with oxygen, producing nitrogen oxide, NO, and nitrogen dioxide, NO2.
<p>What does the flow of N2from NH4+to other biomolecules occur through?</p>
<p>Glutamate</p>
<p>How does glutamate pass on the nitrogen?</p>
<p>By interconverting into other molecules</p>
<p>What are the 4 amino acids in much higher concentrations in cells compared to others?</p>
<p>Alanine</p>
<p>Glutamine</p>
<p>Glutamate</p>
<p>Asparate</p>
<p>What do most organisms do because they cannot fix N2?</p>
<p>Conserve it by transamination</p>
<p>What is transamination?</p>
<p>Transfering amino group between diferent molecules</p>
What does transamination look like?
process by which amino groups are removed from amino acids and transferred to acceptor keto-acids to generate the amino acid version of the keto-acid and the keto-acid version of the original amino acid.
<p>Why is transamination involved in both the synthesis and degradation of nitrogen compounds?</p>
<p>The reactions of transamination are reversible</p>
<p>What do all amino transferases rely on?</p>
<p>The pyruidoxal phosphate cofactor</p>
<p>What is the typical molecule that accepts amino groups?</p>
<p>a-ketoglutamate</p>
<p>What does L-glutamate act as?</p>
<p>A temporary storage of nitrogen</p>
<p>What can L-glutamate do?</p>
<p>Donate amino groups when needed for amino acid biosynthesis</p>
<p>What is pyridoxal phosphate (PLP)?</p>
<p>Cofactor made from vitamin B6 (essential vitamin)</p>
<p>Transfers the amino group during the reaction</p>
<p>What does it mean if aminotransferases are found in the plasma?</p>
<p>There is tissue damage somewhere because aminotransferases are intracellular, this damage is usually in the liver</p>
When do amino acids undergo oxidative catabolism?
Left over amino acids (from normal protein turnover)
Dietary amino acids
Proteins in the body (are broken down when carbohydrates are short)
What happens to dietary proteins?
They are enzymatically hydrolysed
What is the process of dietary proteins being enzymatically hydrolysed?
- Pepsin cuts protein into peptide in the stomach
- Trypsin and chymotrypsin cut proteins and large peptides into smaller peptides in the small intestine
- Aminopeptidase and carboxypeptidase A and B degrade peptides into amino acids in the small intestine
Why is the stomach acidic?
To help breakdown proteins
Where do the enzymes involved in the breakdown of dietary proteins come from?
Gastric glands in stomach lining
Exocrine cells in pancreas
Villi of small intestine
What cellular proteins would be targeted for destruction?
Misfolded proteins
Foreign proteins
Unwanted proteins
How are cellular proteins targeted for destruction?
Ubiquitin tags proteins that are to be degraded
What are the fates of amino acids from broken down proteins?
Left intact for biosynthesis
Broken down into amino groups and carbon skeleton, where the amino group is disposed of in the urea cycle
What are the 3 fates of carbon skeletons from broken down amino acids?
Glucose or glycogen synthesis
Cellular respiration
Fatty acid synthesis
