Dr Praveen Kumar Agrawal is teaching live on Unacademy Plus
Lesson -13 Respiration as an Amphibolic process Dr. P. K. Agrawal M.Sc., Ph.D., CSIR NET (URF), SRF, GATE, FIAZ Youtube Channel with over 1 million views 20 Years of Pre-medical teaching experience Ex Faculty, Allen Career Institute, Kota Visit following link to follow my profile https://unacademy.com/user/biologybypkagrawal-6909
Amphibolism Catabolism involves cut down or degradative processes, in which a larger substrate is broken down into small components. Digestion respiration etc. are such catabolic processes. Anabolism on the other hand are building up processes in which smaller components combine to give rise to a larger molecule. Photosynthesis, protein synthesis etc. are such anabolic processes. There are some processes in which both the above types of reactions occur side by side. Such processes are called Amphibolic processes Respiration is primarily considered as a catabolic process as glucose is broken down into 6 molecules of carbon di oxide. However, respiration forms many key intermediate compounds which can be utilized for the formation and synthesis of new compounds in the body. So, in fact, respiration should be seen as an amphibolic process, rather than mere catabolic process.
. Fatty acids enter the Krebs cycle after being converted into acetyl CoA, by beta oxidation. The reverse of the process can also give rise to fatty acids from acetylICoA . Glycerol enters the respiratory pathway after being converted to PGAL. . The proteins are first degraded to amino acids and then these amino acids undergo either deamination /transamination, depending on their structure and enter Krebs' cycle at some stage . Key intermediates of respiratory pathways can be withdrawn for the synthesis of amino acids and fats. For example, when the organism needs to synthesize fatty acids, the acetyl CoA (important component of Krebs cycle) is withdrawn from the respiratory pathway and can used to synthesize fatty acids. Using same process fatty acids can be synthesized from sugars also and vice versa (gluconeogenesis) In the similar fashion, important key intermediates of the Krebs cycle can be used to synthesize various amino acids. .So, respiratory pathway, especially Krebs cycle is not only oxidative (catabolic), but also anabolic too. Hence it is better called an Amphibolic pathway.
Glucose Lactate Serine Cysteine Threonine Glycine Po Glycolysis pyruvate TRANSAMINASE PyruvateAcetyl-COA PYRUVATE CARBOXYLASE TryptophanAlanine Aspartate Oxaloacetate Tyrosine Phenylalanine Fumarate Krebs cycle Citrate Methionine Valine -Ketoglutarate Co2 TRANSAMINASE Histidine Proline Glutamine Arginine Glutamate
Request! Regularly watch lessons and revise them. Please like, comment and recommend this lesson Follow my profile https://unacademy.com/user/biologybypkagrawal-6909 ALL THE BEST