1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. OC-SBT/ SBI/ SGS034-CP1-04 Introduction Programmes and Courses  SEP – SBT034 – Unit 01  SEP – SBI034 – Unit 01  SEP – SGS034 – Unit 01

3. School of Science and Technology, Online Counseling Resource… Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) ‏ Experience: 11 Years arunmesh@hotmail.com

4. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Define catabolism in plants and mammals. Describe Different biochemical reactions involved in catabolism. Describe various biochemical pathways of catabolic metabolism and its Significances

6. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.6 Introduction - 1  Catabolism is set of biochemical reactions involved in the production of chemical energy and building blocks for the synthesis of new cells and tissues thereafter.  Carbohydrates, fats and proteins are source of energy which is released by catabolism.  90% of this energy comes from the catabolism of carbohydrates and fats.

7. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.7 Introduction - 2  10 to 15% of the energy comes from the catabolism of proteins.  90% of this energy comes from the catabolism of carbohydrates and fats.  10 to 15% of the energy comes from the catabolism of proteins.  In this presentation, you will get overview of catabolism of carbohydrates, fats and proteins.

8. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.8 Catabolism - 1  Catabolism is set of biochemical reactions of breaking down carbohydrates, fats and proteins to obtain energy in chemical form to drive different biosynthesis processes and mechanical jobs of cells.  Catabolic reactions are basically oxidation reactions which uses oxygen.  Catabolic reactions produce chemical energy in forms of ATP molecules and NADPH.

9. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.9 Catabolism - 2  The catabolism is thus breaking down of Carbohydrates Fats proteins

10. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.10 Catabolism Pathway-1  Catabolic pathways in brief:- Three stages of catabolism:- In first stage there is breakdown of Large complex macromolecules of energy source into basic building blocks such as glucose, amino acids and fatty acids and glycerol. In second stage these simple building blocks are oxidized to common metabolite, Acetyl CoA to release the free energy required to drive the anabolic reactions. In third stage energy rich electron released in citric acid cycle is fed into respiratory chain to synthesize ATP molecules.

11. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.11 Catabolism of Carbohydrates  Catabolism of carbohydrates is carried out by the set of biochemical processes known as glycolysis or Embden-Myerof pathway.  The complete glycolysis is shown by chemical reaction as follow: C 6 H 12 O 6 +6O 2 + 6H 2 O +6CO 2 + 686 Kcal/mole

12. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.12 Role of ATP Molecules

13. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.13 Catabolism of Carbohydrates  The total glycolysis of carbohydrates is carried out in two stages: In first stage of glycolysis the carbohydrates are converted into pyruvic acid as follow:  D-glucose +2Pi +2ADP +2NAD+ 2Pyruvate +2ATP +2NADH. This first stage of glycolysis does not require oxygen to convert the glucose molecule into pyruvic acid. In the second stage of glycolysis pyruvic acid is oxidized to CO 2 and water by citric acid cycle.

14. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.14 Catabolism of Fats-1  Energy content of fats is 9Kcal/g; whereas the energy content of carbohydrates is 4Kcal/g.  In the few minutes of exercise, ATP and glycogen reserve of skeleton muscles are used, thereafter fats are the major source of energy for the prolonged muscular activity.

15. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.15 Catabolism of Fats-2  Since the fats are oxidized aerobically via β -oxidation, consumption of oxygen increases 16 folds during the first five minutes of intense muscular activity.

16. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.16 Catabolism of Fats-3  Fats are oxidized solely in mitochondria.  The free fatty acids in cytosol can not pass membranes of mitochondria and therefore have to undergo series of enzymatic reactions which convert the fatty acids to fatty acyl-CoA.  Now this fatty acyl CoA is oxidized in mitochondria to produce energy in form of ATP molecules.

17. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.17 Catabolism of Fats-4  In mitochondria fatty acids in form of fatty acyl CoA is oxidized in two stages: In the first stage fatty acyl CoA is oxidized to Acetyl-CoA and ATP. In the second stage the fatty acids are oxidized to via citric acid cycle to CO 2 and H 2 O. CH 3 (CH 2 )14CO 2 H +23O 2 16CO 2 +16H 2 O+ 130 ATP

18. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.18 Catabolism of Proteins-1  Catabolism of proteins contribute only 10% to 15% of total energy.  Amino acids produced after the breaking down of proteins enter the catabolic pathways.  The alpha amino group of 20 amino acids is removed during the first stage of degradation of amino acids by enzyme, aminotransferase.

19. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.19 Catabolism of Proteins-2  If this removed alpha amino group is not utilized for the synthesis of new amino acid of any other nitrogenous compound then it is excreted from the body in form of urea.  Aminotransferase transfer amino group from alpha carbon of amino acid to alpha ketoglutarate, producing alpha keto acid and L-glutamate.  L-glutamate is common acceptor of amino group from amino acids.

20. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.20 Catabolism of Proteins-3  L-glutamate thus formed is either utilized in biosynthesis reactions or enter into citric acid cycle.  However different amino acids enter the citric acid cycle as different intermidiates.  For example, arginine, histidine, glutamine and proline enter the citric acid cycle as glutamate.  Isoleucine, methionine and valine enter the citric acid cycle as succinyl-CoA.

21. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.21 Catabolism of Proteins-4  Phenylalanine and tyrosine enter the citric acid cycle as fumarate.  Aspartate and asparagine enter the citric acid cycle as oxaloacetate.  Phenylalanine, tyrosine, leucine lysine tryptophan enter the citric acid cycle as acetyl-CoA via acetoacetate-CoA.  Alanine, threonine, glycine serine and cysteine enter the citric acid cycle as acetyl-CoA via pyruvate.

22. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.22 Hormonal Control of Catabolism  Metabolism of carbohydrates is controlled by following hormones: Insulin Glucagon Epinephrine Glucocoticosteroid Thyroid hormones Glucagon and epinephrine have opposite effects to that of insulin.

23. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.23 Hormonal Control of Catabolism-2  Insulin :- Insulin control uptake of glucose by cells. Insulin stimulates glycolysis. Insulin inhibits gluconeogenesis. Insulin stimulates synthesis of triglycerol and its breakdown. Insulin stimulates synthesis of glycogen and its breakdown.

24. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.24 Hormonal Control of Catabolism-3  Glucagon:- It is secreted by alpha cells of pancreas in response to low blood glucose level. Glucagon stimulates glycogen breakdown.  Epinephrine (adrenaline) :- It is secreted by adrenal gland. Epinephrine stimulates breakdown of glycogen to glucose 1-phosphate which then converted into glucose 6-phosphate.

25. School of Science and Technology, Online Counseling Resource… What We Learn…..  Concept of catabolism.  Carbohydrates, fats and proteins are source of energy which is released by catabolism.  Catabolic reactions are basically oxidation reactions which uses oxygen.  Catabolism of proteins contribute only 10% to 15% of total energy.  L-glutamate is common acceptor of amino group from amino acids.

26. School of Science and Technology, Online Counseling Resource… Critical Thinking Question  In healthy mammals which organic compound is predominantly involved in catabolism as starting material?

27. School of Science and Technology, Online Counseling Resource… Tips for Critical Thinking Question  Organic compound that is abundantly available as energy source in nature.

28. School of Science and Technology, Online Counseling Resource… Study Tips  Book Title: Fundamentals of Biochemistry Title: Fundamentals of Biochemistry Author:Dr. J. L Jain Author: Dr. J. L Jain Publication: Publication: W S. Chand and Co., New Delhi. Book Title: Principles of Biochemistry Author:Dr. H Robert Horton Author: Dr. H Robert Horton Publication: Publication: W S. Chand and Co., New Delhi.

29. End of the Presentation Thank You !