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Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India OC-SEP033-CP01-02 Introduction Programmes and Courses SEP – SBT033 – Unit 01 SEP – SBI033 – Unit 01 SEP – SGS033 – Unit 01 School of Science and Technology, Online Counseling Resource… Credits Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) Experience: 11 Years. [email protected] © 2007, YCMOU. All Rights Reserved. 3 School of Science and Technology, Online Counseling Resource… 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. © 2007, YCMOU. All Rights Reserved. 4 School of Science and Technology, Online Counseling Resource… Learning Objectives After studying this module, you should be able to: Describe digestion of proteins Describe various digestive end products of proteins Describe various digestive enzymes involve in digestion of proteins. Explain the action of various digestive enzymes. © 2007, YCMOU. All Rights Reserved. 5 School of Science and Technology, Online Counseling Resource… Introduction Proteins provide all required amino acids for the various amino acid in mammals. For this dietary proteins have to digested to their absorbable forms i. e. amino acids. The digestion of dietary proteins involved the hydrolysis of peptide bonds breaking down the proteins to their building blocks i. e. amino acids which are then absorbed from the small intestine. In this presentation you will learn where and how proteins are digested. © 2007, YCMOU. All Rights Reserved. 6 School of Science and Technology, Online Counseling Resource… Digestion of Proteins-1 Digestion of proteins are carried out in three stages: 1st stage: 2nd stage: proteins are partially digested in stomach by pepsin enzyme. Proteins are digested into dipeptides ant tripeptides by the proteolytic enzymes trypsin, chymotrypsin, carboxypolypeptidase and proelastase secreted by pancreas. 3rd stage: Final digestion of proteins into amino acids is achieved in enterocytes cells lining the villi of upper portion of small intestine. © 2007, YCMOU. All Rights Reserved. 7 School of Science and Technology, Online Counseling Resource… Digestion of Proteins-2 Proteins In Stomach HCL + pepsin peptones/small peptides Trypsin and Chymotrypsin by pancreas. Carboxypeptidase (pancreas) Aminopeptidase(small intestine Amino acids © 2007, YCMOU. All Rights Reserved. 8 School of Science and Technology, Online Counseling Resource… Digestion of Proteins in Stomach Digestion of proteins begin in stomach and is completed in intestine and enterocytes of small intestine. In stomach proteins are partially digested by pepsin to preteoses, peptones and small polypeptides. Pepsin digest the collagen fibres holding muscle fibres together and thus make digestion of meat easy in small intestine since the proteins digesting enzymes in small intestine can easily attach the meat fibres released from collagen bindings. © 2007, YCMOU. All Rights Reserved. 9 School of Science and Technology, Online Counseling Resource… Digestion of Proteins in Intestine-1 Partially digested proteins are completely digested into amino acids in upper small intestine, in duodenum and jejunum by the proteolytic enzymes secreted by pancreas. Pancreas secretes four important proteolytic enzymes which are: Trypsin, Chymotrypsin, Carboxypolypeptidase, Proelastase. © 2007, YCMOU. All Rights Reserved. 10 School of Science and Technology, Online Counseling Resource… Digestion of Proteins in Intestine-2 Trypsin and chymotrypsin break proteins molecules into small polypeptide chains. Carboxypolypeptidase then cleaves individual amino acids from carboxyl ends of the small peptide chains. Proelastase is converted into elastase which break down the elastin fibres holding together the meat fibres. Thus in upper small intestine all proteins are degraded into dipeptides and tripeptides by the above mentioned enzymes secreted by pancreas. © 2007, YCMOU. All Rights Reserved. 11 School of Science and Technology, Online Counseling Resource… Digestion of Proteins in Intestine-3 Final digestion of proteins occurs on the membrane microvilli of small intestine. The peptidases aminopolypeptidase, dipeptidase present on these membranes break larger polypeptides into dipeptides and tripeptides and few amino acids. When these dipeptides and tripeptides enter into the cytosol of the enterocytes of the microvilli the specific peptidases present in these cytosols degrade the dipeptides and tripeptides into amino acids. © 2007, YCMOU. All Rights Reserved. 12 School of Science and Technology, Online Counseling Resource… Absorption of Amino Acids The amino acids obtained from proteins digestion are transported into intestinal epithelial cells by the sodium co-transport mechanism involving specific transport proteins. Amino acids obtained from proteins as result of digestion are absorbed from the other sides of enterocytes into blood. © 2007, YCMOU. All Rights Reserved. 13 School of Science and Technology, Online Counseling Resource… Effects of Intoxicants on Digestion Effects of alcohol on digestion: alcohol disturb the digestion in three ways: It bring about dehydrosis of food stuff especially animal meat making it tough for the penetration of digestive juices into it and thus difficult to digestion. Alcohol denature and precipitate the enzyme pepsin, main constituent of gastric juice making it actionless. Alcohol causes gastric dyspepsia, causing constriction of gastric gland opening and thus hampering the absorption of food liquid from stomach. © 2007, YCMOU. All Rights Reserved. 14 School of Science and Technology, Online Counseling Resource… What We Learn….. Digestion of proteins in various organs of alimentary canal. Digestion of proteins in stomach. Digestion of proteins in small intestine. Enzymes involved in digestion of proteins. Mechanism of absorption of end products of protein digestion. © 2007, YCMOU. All Rights Reserved. 15 School of Science and Technology, Online Counseling Resource… Critical Thinking Question Why person omit after taking protein rich food along with abnormal dose of alcohol ? © 2007, YCMOU. All Rights Reserved. 16 School of Science and Technology, Online Counseling Resource… Tips for Critical Thinking Question Alcohol causes denaturation of proteins. © 2007, YCMOU. All Rights Reserved. 17 School of Science and Technology, Online Counseling Resource… Study Tips Book Title: Textbook of medical physiology. Author: Dr. Arthur C. Guyton, John E. Hall. Publication: Elsevier India Private Limited. Book Title: Human Physiology Author: C. C. Chattergy. Publication: -- © 2007, YCMOU. All Rights Reserved. 18 End of the Presentation Thank You!