A person had roti and dal for his lunch. Trace the changes in those during its passage through the alimentary canal.
A person had roti and dal for his lunch. Trace the changes in those during its passage through the alimentary canal.
Digestion of Roti' (Carbohydrates) (a) Digestion of Carbohydrates in the Oral Cavity In oral cavity, the roti is mixed with saliva. The saliva contains an enzyme salivary amylase (ptyalin) which converts starch in roti into maltose, isomaltose and small dextrins called α-dextrin 30% of starch is hydrolysed in the oral cavity. StrachSalivaryAmylase−−−−−−−−−−→pH6−8Maltose+Isomaltose+α−Dextrin
(b) Digestion of Carbohydrates in the Small Intestine The passage of party digested roti from oral cavity to oesophagus and then to stomach is regulated by peristalsis (the successive waves of muscular contraction in oesophagus). The stomach stores the food for 4-5 hours. The gastric juice does not contain carbohydrate digesting enzyme. The partially digested food is now called as chyme. In intestine, following action occurs. (i) Action of Pancreatic Juice Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides. Polysaccharides(starch)Amylase−−−−−→Disaccharides (ii) Action of Intestinal Juice Intestinal juice contain maltase, isomaltase, sucrase (invertase), lactase and a-dextrinase.These enzymes act on food converting it into simpler compounds like glucose, fructose, galactose, etc.MaltoseMaltose−−−−−→Glucose+GlucoseIsomaltoseIsomaltose−−−−−−→Glucose+GlucoseSucroseSucrase−−−−−→Glucose+GlucoseLactaseLactase−−−−→Glucose+Glucoseα−Dextrinsα−dextrinose−−−−−−−−→Glucose
Digestion of Protein Proteins are made up of amino acids. So proteins are broken down to amino acid during the process of digestion. Saliva does not contain any protein digesting enzyme. So, its digestion in stomach. (a) Digestion of Protein in Stomach The stomach normally stores food for 4-5 hours. The gash is glands of the stomach secrete gastric juice. It contains HCI, proenzymes like- pepsinogen and prorennin. Various reactions in stomach are discussed below
Pepsinogen(proenzyme)HCl−−→PepsinProteinsPepsin−−−−→Peptones and proteosesProrennin(proenzyme)HCl−−→Rennin
(b) Digestion of Protein in Small Intestine (i) Action of Pancreatic Juice The enzymes trypsinogen. chymotrypsinogen and procarboxypeptidase in pancreatic juice are all concerned with the protein digestion. Some reactions are given below
TrypsinogenEnterot kinase−−−−−−−−−→TrypsinProteinsTrypsin−−−−−→DipeptidesChymotrypsinogenTrypsin−−−−−→ChymotrypsinPeptonesChymotrypsin−−−−−−−−−→DipeptidesProcarboxypeptidaseTrypsin−−−−−→CarboxypeptidasesProteosesCarboxypeptidases−−−−−−−−−−−→Dipeptides
Action of Intestinal Juice Intestinal juice contain enzymes enterokinase, amino peptidase and dipeptidase and their actions are given below PeptidesAmino peptidase−−−−−−−−−−→Amino acidDipeptidesDipeptides−−−−−−→Amino acid
The macromolecules that are broken down into simpler components are the products of roti and dal (carbohydrates and proteins) which are further absorbed by the villi in intestine and the rest undigested food is removed in the form of faeces.
Digestion of Roti' (Carbohydrates) (a) Digestion of Carbohydrates in the Oral Cavity In oral cavity, the roti is mixed with saliva. The saliva contains an enzyme salivary amylase (ptyalin) which converts starch in roti into maltose, isomaltose and small dextrins called α-dextrin 30% of starch is hydrolysed in the oral cavity. StrachSalivaryAmylase−−−−−−−−−−→pH6−8Maltose+Isomaltose+α−Dextrin
(b) Digestion of Carbohydrates in the Small Intestine The passage of party digested roti from oral cavity to oesophagus and then to stomach is regulated by peristalsis (the successive waves of muscular contraction in oesophagus). The stomach stores the food for 4-5 hours. The gastric juice does not contain carbohydrate digesting enzyme. The partially digested food is now called as chyme. In intestine, following action occurs. (i) Action of Pancreatic Juice Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides. Polysaccharides(starch)Amylase−−−−−→Disaccharides (ii) Action of Intestinal Juice Intestinal juice contain maltase, isomaltase, sucrase (invertase), lactase and a-dextrinase.These enzymes act on food converting it into simpler compounds like glucose, fructose, galactose, etc.MaltoseMaltose−−−−−→Glucose+GlucoseIsomaltoseIsomaltose−−−−−−→Glucose+GlucoseSucroseSucrase−−−−−→Glucose+GlucoseLactaseLactase−−−−→Glucose+Glucoseα−Dextrinsα−dextrinose−−−−−−−−→Glucose
Digestion of Protein Proteins are made up of amino acids. So proteins are broken down to amino acid during the process of digestion. Saliva does not contain any protein digesting enzyme. So, its digestion in stomach. (a) Digestion of Protein in Stomach The stomach normally stores food for 4-5 hours. The gash is glands of the stomach secrete gastric juice. It contains HCI, proenzymes like- pepsinogen and prorennin. Various reactions in stomach are discussed below
Pepsinogen(proenzyme)HCl−−→PepsinProteinsPepsin−−−−→Peptones and proteosesProrennin(proenzyme)HCl−−→Rennin
(b) Digestion of Protein in Small Intestine (i) Action of Pancreatic Juice The enzymes trypsinogen. chymotrypsinogen and procarboxypeptidase in pancreatic juice are all concerned with the protein digestion. Some reactions are given below
TrypsinogenEnterot kinase−−−−−−−−−→TrypsinProteinsTrypsin−−−−−→DipeptidesChymotrypsinogenTrypsin−−−−−→ChymotrypsinPeptonesChymotrypsin−−−−−−−−−→DipeptidesProcarboxypeptidaseTrypsin−−−−−→CarboxypeptidasesProteosesCarboxypeptidases−−−−−−−−−−−→Dipeptides
Action of Intestinal Juice Intestinal juice contain enzymes enterokinase, amino peptidase and dipeptidase and their actions are given below PeptidesAmino peptidase−−−−−−−−−−→Amino acidDipeptidesDipeptides−−−−−−→Amino acid
The macromolecules that are broken down into simpler components are the products of roti and dal (carbohydrates and proteins) which are further absorbed by the villi in intestine and the rest undigested food is removed in the form of faeces.
