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>
<p>When do amino acids undergo oxidative catabolism?</p>
<p>Left over amino acids (from normal protein turnover)</p>
<p>Dietary amino acids</p>
<p>Proteins in the body (are broken down when carbohydrates are short)</p>
<p>What happens to dietary proteins?</p>
<p>They are enzymatically hydrolysed</p>
<p>What is the process of dietary proteins being enzymatically hydrolysed?</p>
<ol> <li>Pepsin cuts protein into peptide in the stomach</li> <li>Trypsin and chymotrypsin cut proteins and large peptides into smaller peptides in the small intestine</li> <li>Aminopeptidase and carboxypeptidase A and B degrade peptides into amino acids in the small intestine</li></ol>
<p>Why is the stomach acidic?</p>
<p>To help breakdown proteins</p>
<p>Where do the enzymes involved in the breakdown of dietary proteins come from?</p>
<p>Gastric glands in stomach lining</p>
<p>Exocrine cells in pancreas</p>
<p>Villi of small intestine</p>
<p>What cellular proteins would be targeted for destruction?</p>
<p>Misfolded proteins</p>
<p>Foreign proteins</p>
<p>Unwanted proteins</p>
<p>How are cellular proteins targeted for destruction?</p>
<p>Ubiquitin tags proteins that are to be degraded</p>
<p>What are the fates of amino acids from broken down proteins?</p>
<p>Left intact for biosynthesis</p>
<p>Broken down into amino groups and carbon skeleton, where the amino group is disposed of in the urea cycle</p>
<p>What are the 3 fates of carbon skeletons from broken down amino acids?</p>
<p>Glucose or glycogen synthesis</p>
<p>Cellular respiration</p>
<p>Fatty acid synthesis</p>
