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Cellular Metabolism

Cellular Metabolism. So we know that the broken down nutrients enter the blood stream either directly (carb’s/glucose & amino acids) or via the lymphatic system (fats) …..but what happens to them now?. Well…these basic nutrients are now used for cellular metabolism.

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Cellular Metabolism

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  1. Cellular Metabolism

  2. So we know that the broken down nutrients enter the blood stream either directly (carb’s/glucose & amino acids) or via the lymphatic system (fats) …..but what happens to them now?

  3. Well…these basic nutrients are now used for cellular metabolism.

  4. Description of Metabolism … the chemical changesthat nutrients undergo from the time they are absorbed from the digestive tract into the blood… to the time they are used as the building blocks of new molecules and tissues in the body… or … are excreted as waste matter …

  5. The end result of cellular metabolism: • Units of energy in the form of ATP • Production of the building blocks for other tissues which are then manufactured within the mitochondrion and the cell

  6. Metabolism produces energy…. • By a process called…. CATABOLISM….which means “breaking down into smaller parts” (catabolism involves the Krebs Cycle in the mitochondrion….more about this later )

  7. The production of the building blocks… • … these building blocks are then used to synthesize other molecules and tissues … • FATS – cholesterol and lipids • CARB’S - glycerol • PROTEINS - in for eg. muscles … This process is called ANABOLISM (anabolism occurs outside the mitochondrion but still within the cytoplasm of the cell)

  8. Catabolism explained in more detail … Remember that a form of catabolism has already occurred in the digestive tract to break up the big fat, carb and protein molecules into smaller units…

  9. Catabolism of Carbohydrates

  10. Catabolism of Carbohydrates … • The end product of carbohydrate catabolism in the cell is a simple sugar or monosaccharide GLUCOSE

  11. Other simple sugars are: * fructose * galactose * mannose In fact any sugar that has 6 Carbons in its structure ( these are the monosaccharides called the hexoses eg. glucose)

  12. Monosaccharides Glucose has 6 carbon’s in it’s molecular structure

  13. Disaccharides • This is 2 6-C molecules together …either 2 identical OR 2 different 6-C molecules • Maltose = 2 X glucose • Lactose = glucose + galactose • Sucrose = glucose + fructose

  14. polysaccharides These are very large molecules made up of many simple sugar units to form branched or linear structures

  15. Catabolism of Proteins

  16. Catabolismof Proteins… • The end product of the catabolism of proteins is … amino acids

  17. CATABOLISM of Proteins Food Food cell proteins pyruvate mitochondrion AA’s Krebs Cycle (CAC) Acetyl CoEA Ammonia as a waste product in urine/sweat/ breath Energy out of mitochondrion Oxygen in…

  18. Catabolism of Fats

  19. Catabolism ofFats … • The end product of the breakdown of fats is: * Glycerol * Fatty acids– these provide the carbon in the Krebs Cycle

  20. CATABOLISM of Fats Food Food Fats (triglycerides) cell palmitate mitochondrion Fatty acids glycerol Krebs Cycle (CAC) Acetyl CoEA Energy out of mitochondrion Oxygen in… Liver

  21. How come more energy is generated from the breakdown of fats than either protein or carb’s?

  22. The answer is simple actually…. *Bearing in mind that for each molecule of acetyl Coenzyme A that enters the Krebs…12 ATP’s are produced* • Glucose = 6C molecule » generates 2 X pyruvates » 2 acetyl coenzymeA’s to enter the Krebs Cycle in the mitochondrion »24 ATP’s are produced. • Fatty Acids = 16C molecules » makes 8 X acetyl CoenzymeA molecules to enter Krebs » 96 ATP’s produced… ie.much more energy…

  23. Or even simpler really…… • …. The amount of energy (ATP) released from the catabolism of fats, proteins or carb’s will depend on … … The number of Carbon atoms in the INDIVIDUAL or SIMPLEST molecule …

  24. A simple explanation of the Kreb’s Cycle … • In the mitochondria • Also called the Citric Acid Cycle • Requires O2 to generate energy – therefore aerobic or also called oxidative metabolism • ProducesCO2 and H2O as by-products of the process *REMEMBER…..that for each molecule of acetyl Coenzyme A that enters the Krebs…12 ATP’s are produced* * THIS IS A CATABOLIC PROCESS and involves numerous coenzymes in the process*

  25. Now the CO2 and H2O generated from the Kreb’s Cycle … … AND the generated energy… is used for the ANABOLIC processes involved in the synthesis of NEW carb’s, proteins and fats outside the mitochondria … in the cytoplasm.

  26. Krebs (Citric Acid) Cycle

  27. A “real life” mitochondrion(taken with an electron microscope)

  28. Coenzymes … So now what are these Coenzyme molecules and what purpose do they serve?

  29. All chemical reactions require the action of enzymes Coenzymes in turn, are required for the enzymes to function properly *without these coenzymes, the enzymes would not be able to catalyze chemical reactions* Many vitamins are coenzymes

  30. All pyruvate from glucose and amino acids is chemically changed to Acetyl CoA … which is vital for aerobic metabolism to occur within the cell. Likewise…all palmitic acid generated from the catabolism of fatty acids is also converted to Acetyl CoA. An example of a vital coenzyme in the Krebs Cycle is Acetyl Coenzyme A.

  31. An very simplified diagram showing just some of the chemical reactions in a cell

  32. So how complex is cellular metabolism really? • Pretty very much complex!!!! • … and beyond the needs of our understanding just now…..

  33. So …. …all we have to really remember about cellular metabolism is this… • In the CYTOPLASM of EACH and EVERY CELL it takes ENERGY to break nutrients down…(NO O2 is used!!!) … THIS IS METABOLISM ! • But … energy is GENERATED 10-fold in the MITOCHONDRION within the cell with the use of O2 … … THIS IS ALSO METABOLISM ! • Now this energy is used to rebuild the other vital molecules WITHIN the CYTOPLASM … AGAIN… … AND THIS … IS ALSO METABOLISM !!! … and so the cycle continues….

  34. Thank you for your patience…. This was a lot of fun to do….

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