Digestion in the Stomach
EXPERIMENT NO. 12
DIGESTION IN THE STOMACH
ABSTRACT____________________________________________________________________________
Digestion refers to the mechanical and chemical breakdown of food into smaller components that can undergo absorption. The objective of this experiment is to investigate mainly the process of digestion in the stomach. The conditions at which the enzymes responsible for the digestion process were determined. Also, the total and free acidity of gastric juice of the sample were calculated. The procedure was divided into three main parts: (1) peptic digestion, (2) rennin test and (3) gastric analysis. Separate preparations were made in each part. In analysis of peptide digestion, determination of the presence of polypeptide chains and the extent of digestion through the hard-boiled egg white was performed. All of the test tubes were positive for Biuret test which indicates presence of polypeptide chains while for the rennin test, curd formations were observed in test tubes 3 and 4 only. In gastric analysis, the values for free acidity and total acidity were computed. The free acidity is 20.83 N NaOH/ 100 ml sample while the total acidity is 20.0 N NaOH /100 ml sample. Lactic test was also performed in in relation with the gastric analysis. Addition of gastric juice to FeCl2 was done to determine the presence of lactic acid, in which a distinct canary yellow color gives a positive result for the test. The colors obtained were dark yellow (gastric juice) and pale yellow (FeCl3) which indicates a positive result. Though the values gathered were acceptable, errors were inevitable. Inaccuracy in burette reading may be the most contributing factor of the errors obtained (in gastric analysis). Errors due to the experimenter’s skills and techniques in performing were taken into consideration based on the values acquired.
DISCUSSION OF DATA AND RESULTS______________________________________________________
The stomach is a saclike portion of
DIGESTION IN THE STOMACH
ABSTRACT____________________________________________________________________________
Digestion refers to the mechanical and chemical breakdown of food into smaller components that can undergo absorption. The objective of this experiment is to investigate mainly the process of digestion in the stomach. The conditions at which the enzymes responsible for the digestion process were determined. Also, the total and free acidity of gastric juice of the sample were calculated. The procedure was divided into three main parts: (1) peptic digestion, (2) rennin test and (3) gastric analysis. Separate preparations were made in each part. In analysis of peptide digestion, determination of the presence of polypeptide chains and the extent of digestion through the hard-boiled egg white was performed. All of the test tubes were positive for Biuret test which indicates presence of polypeptide chains while for the rennin test, curd formations were observed in test tubes 3 and 4 only. In gastric analysis, the values for free acidity and total acidity were computed. The free acidity is 20.83 N NaOH/ 100 ml sample while the total acidity is 20.0 N NaOH /100 ml sample. Lactic test was also performed in in relation with the gastric analysis. Addition of gastric juice to FeCl2 was done to determine the presence of lactic acid, in which a distinct canary yellow color gives a positive result for the test. The colors obtained were dark yellow (gastric juice) and pale yellow (FeCl3) which indicates a positive result. Though the values gathered were acceptable, errors were inevitable. Inaccuracy in burette reading may be the most contributing factor of the errors obtained (in gastric analysis). Errors due to the experimenter’s skills and techniques in performing were taken into consideration based on the values acquired.
DISCUSSION OF DATA AND RESULTS______________________________________________________
The stomach is a saclike portion of
References: __________________________________________________________________________ Bowen, R. Parietal Cell : Mecahnism of Acid Secretion. Date retrieved: 25 September 2012. Retrieved from http://www.vivo.colostate.edu/hbooks/pathphys/digestion/stomach/parietal.html HIckman, Jr., C. P., Roberts, L. S., & Allan, L. (1993). Integrated Principles of Zoology(9th ed.). Manila, Philippines: Merriam and Webster Bookstore Inc Hutchison, I. Milk And Milk Products. Part 3: Milk Digestion. p. 122. Date retrieved : 26 September 2012. Retrieved from: http://chestofbooks.com/health/nutrition/Disease-Food/Milk-And-Milk-Products-Part-3-Milk-Digestion.html Miller, K. R., & Levine, J. S. (2003). Prentice Hall Biology. Jurong, Singapore: Pearson Education Inc Raven, P. H., Johnson, G. B., & Jonathan, L. B. (2005). Biology (7th ed.). New York, U.S.A.: McGraw Hill Inc