Gastro intestinal hormones/Digestive enzymes Questions in English

(C) Amylopsin is another name for pancreatic amylase.
Pancreatic amylase is an enzyme secreted by the pancreas into the small intestine.
It functions optimally in an alkaline medium (pH $7.1$ to $8.2$) provided by the bicarbonate ions in pancreatic juice.
It breaks down polysaccharides like starch into disaccharides such as maltose.

(B) Ptyalin,also known as salivary amylase,is an enzyme found in human saliva.
It functions optimally at a $pH$ of approximately $6.8$,which is slightly acidic.
Therefore,the correct option is $B$.

(B) The hormone $Cholecystokinin$ $(CCK)$ is secreted by the duodenal mucosa.
It acts on the gall bladder to stimulate its contraction,which results in the release of bile into the duodenum to aid in the digestion of fats.

(D) Trypsinogen is an inactive proenzyme (zymogen) secreted by the pancreas into the small intestine.
It is activated into its active form,trypsin,by an enzyme called enterokinase (also known as enteropeptidase).
Enterokinase is secreted by the intestinal mucosa.
Once formed,trypsin further activates other pancreatic enzymes like chymotrypsinogen and procarboxypeptidase.

(D) $Trypsin$ is a proteolytic enzyme secreted by the pancreas in an inactive form called $trypsinogen$.
It is activated by $enterokinase$ in the duodenum.
$Trypsin$ functions optimally in the alkaline environment of the small intestine (duodenum),where it breaks down proteins into peptides and amino acids.

(D) Enzymes are biological catalysts that speed up chemical reactions in the body.
During the process of digestion,enzymes break down complex,insoluble food molecules (such as polysaccharides,proteins,and fats) into simpler,soluble forms (such as monosaccharides,amino acids,and fatty acids) that can be easily absorbed by the intestinal wall into the bloodstream.
Therefore,the correct answer is $D$.

(A) Proteolytic enzymes are those enzymes that catalyze the breakdown of proteins into smaller polypeptides or amino acids.
Trypsin is a pancreatic enzyme that breaks down proteins in the small intestine.
Peptidase is an enzyme that breaks down peptides into amino acids.
Pepsin is a gastric enzyme that initiates protein digestion in the stomach.
Therefore,the correct group of proteolytic enzymes is trypsin,peptidase,and pepsin.

(B) $Trypsin$ is a proteolytic enzyme found in the pancreatic juice. It is secreted in an inactive form called $trypsinogen$,which is activated by $enterokinase$ in the small intestine. $Trypsin$ specifically breaks down proteins into smaller peptides and amino acids.

(D) The digestion of carbohydrates is primarily carried out by amylase enzymes.
$Amylopsin$ is the pancreatic amylase that breaks down complex carbohydrates into simpler sugars like maltose.
$Erepsin$ is involved in protein digestion (peptides to amino acids).
$Steapsin$ is pancreatic lipase,which acts on fats.
$Pepsin$ is a gastric enzyme that digests proteins.
Therefore,the correct option is $D$.

(A) Trypsin and pepsin are both endopeptidase enzymes.
Trypsin functions optimally in an alkaline medium (pH $7.5-8.5$) in the small intestine.
Pepsin functions optimally in an acidic medium (pH $1.5-2.5$) in the stomach.
Therefore,trypsin differs from pepsin because it digests protein in an alkaline medium,whereas pepsin digests protein in an acidic medium.

(B) The $pH$ value of $1.6$ indicates a highly acidic environment, which is characteristic of the human stomach.
$Pepsin$ is a proteolytic enzyme that functions optimally in an acidic medium, specifically at a $pH$ range of $1.5$ to $2.5$.
$Trypsin$ and $Erepsin$ function in the small intestine at an alkaline $pH$, while $Amylase$ is responsible for carbohydrate digestion, not protein digestion.
Therefore, $Pepsin$ is the correct enzyme to digest protein at $pH$ $1.6$.

(A) $Rennin$ is a proteolytic enzyme found in the gastric juice of infants.
It specifically acts on $Casein$,which is a milk protein,and converts it into calcium paracaseinate.
This process is known as the curdling of milk,which helps in the digestion of milk proteins.
Other options are incorrect because $Amylase$ acts on starch,$Trypsin$ acts on proteins,and $Invertase$ acts on sucrose.

(B) The enzyme $Rennin$ (also known as $Chymosin$) is a proteolytic enzyme found in the gastric juice of infants. It specifically acts on the milk protein $Caseinogen$ (a soluble protein) and converts it into $Paracasein$ (an insoluble protein),which then reacts with calcium ions to form calcium paracaseinate (curd). This process facilitates the digestion of milk protein by $Pepsin$.

(A) In the process of human digestion,hydrochloric acid $(HCl)$ acts as an activator that converts the inactive zymogen pepsinogen into its active form,pepsin.
Similarly,enterokinase (also known as enteropeptidase) is an enzyme secreted by the intestinal mucosa that acts as an activator to convert the inactive zymogen trypsinogen into its active form,trypsin,in the small intestine.
Therefore,the relationship is one of an activator to its respective inactive proenzyme.

(D) Brunner's glands are located in the submucosa of the duodenum.
These glands secrete an alkaline mucus that helps protect the duodenal wall from acidic chyme.
Additionally,the cells of the duodenal mucosa secrete hormones such as $Secretin$ and $Cholecystokinin$ $(CCK)$ in response to the presence of chyme.
Therefore,the correct option is $D$.

(A) Maltase is a digestive enzyme found in the small intestine that catalyzes the hydrolysis of maltose into two molecules of glucose.
This enzymatic reaction occurs in the small intestine,where the environment is slightly alkaline,typically having a $pH$ greater than $7$ (usually around $8.0$ to $8.5$ due to the presence of bile and pancreatic juice).

(B) Trypsin is considered a universal enzyme because it is found in organisms ranging from protozoa to mammals.
It plays a crucial role in the digestion of proteins across various phyla in the animal kingdom.

(C) $Secretin$ is a hormone secreted by the mucosa of the duodenum.
It stimulates the secretion of pancreatic juice and increases duodenal movements.
Thus,it plays an important role in the process of digestion.

(D) is the correct answer.
Enterogastrone is a hormone secreted by the duodenal epithelium.
It functions to inhibit gastric secretion and motility,whereas Enterokinase,Amylase,and Trypsin are all enzymes involved in the digestive process.

(C) is the correct answer.
Pancreatic lipase,historically known as $Steapsin$,is the primary enzyme responsible for the digestion of fats.
It hydrolyzes fats (triglycerides) into glycerol and fatty acids.
In other options: $Lactose$ is digested by $Lactase$,$Starch$ is digested by $Amylase$ (into $Maltose$),and $Casein$ is digested by $Renin$ (in infants) or $Pepsin$.

(C) $Enterocrinin$ is a hormone released by the mucosa of the small intestine.
It is specifically produced in response to the mechanical stimulation of the villi by the presence of food.
This hormone stimulates the intestinal glands to secrete intestinal juice,also known as $succus$ $entericus$.

(D) The presence of fat in the stomach and duodenum triggers the release of hormones such as enterogastrone (also known as gastric inhibitory peptide or $GIP$).
These hormones act to inhibit the secretion of gastrin and reduce gastric motility,which slows down the emptying of the stomach to allow for more efficient digestion of fats.

(D) $Gastrin$ is a polypeptide hormone secreted by the pyloric mucosa of the stomach. It acts on the gastric glands to stimulate the secretion of gastric juice,which contains $HCl$ and pepsinogen.

(C) $Cholecystokinin$ $(CCK)$ is a peptide hormone produced by the $I$-cells of the mucosa of the duodenum and jejunum.
It acts on the gall bladder to stimulate its contraction,which results in the release of bile into the duodenum.
It also stimulates the pancreas to release pancreatic enzymes.
Therefore,the correct option is $C$.

(D) ,$B$,and $C$ are proteolytic enzymes.
$Pepsin$ is a gastric enzyme that breaks down proteins into peptides.
$Trypsin$ is a pancreatic enzyme that breaks down proteins in the small intestine.
$Erepsin$ is an intestinal enzyme that completes protein digestion.
$Renin$ (option $D$) is a hormone secreted by the $JGA$ (Juxtaglomerular apparatus) in the kidney,which regulates blood pressure and fluid balance,not a digestive enzyme.

(D) $Rennin$ is a proteolytic enzyme secreted in the stomach of young mammals.
It converts the soluble milk protein $casein$ into insoluble and semi-solid $calcium \text{ } paracaseinate$.
This process is known as the curdling of milk, which helps in the digestion of milk proteins.

(C) $Trypsin$ is a proteolytic enzyme found in the pancreatic juice. It acts on proteins in the small intestine under alkaline conditions to break them down into smaller peptides and peptones.

(B) . $Enterokinase$ is a gastro-intestinal enzyme secreted by the small intestine of vertebrates,which converts $trypsinogen$ to $trypsin$.

(A) Pepsin and trypsin are proteolytic enzymes (proteases) that catalyze the hydrolysis of proteins into smaller peptides or amino acids.
$A$. Rennin (also known as chymosin) is a proteolytic enzyme found in the gastric juice of infants that helps in the digestion of milk protein (casein).
$B$. Sucrose is a disaccharide carbohydrate,not an enzyme.
$C$. Thyroxin is a hormone secreted by the thyroid gland,not an enzyme.
$D$. Secretin is a gastrointestinal hormone that regulates the secretion of gastric acid and pancreatic bicarbonate,not an enzyme.
Therefore,rennin belongs to the same class of enzymes as pepsin and trypsin.

(A) The hormone 'secretin' is produced by the duodenal mucosa in response to acidic chyme entering the small intestine.
It primarily acts on the exocrine pancreas to stimulate the secretion of water and bicarbonate ions,which form the bulk of pancreatic juice.
Therefore,the correct option is $A$.

(A) Cholecystokinin $(CCK)$ and duocrinin are gastrointestinal hormones.
These hormones are secreted by the mucosa of the small intestine.
Specifically,$CCK$ is secreted by the $I$-cells of the duodenum and jejunum,while duocrinin is secreted by the duodenal mucosa to stimulate the secretion of mucus by Brunner's glands.
Therefore,the correct answer is the intestine.

(C) The hormone $Cholecystokinin$ $(CCK)$ is secreted by the duodenal mucosa. Its primary function is to stimulate the contraction of the gall bladder and the relaxation of the sphincter of $Oddi$,which facilitates the release of bile into the duodenum to aid in the digestion of fats.

(B) $Succus$ $entericus$ is the intestinal juice secreted by the intestinal glands. Its secretion is primarily stimulated by the hormones secretin and cholecystokinin $(CCK)$. Secretin stimulates the secretion of water and bicarbonate ions,while $CCK$ stimulates the secretion of digestive enzymes from the pancreas and also influences the intestinal mucosa to release intestinal juice.

(C) Cholecystokinin $(CCK)$ is a gastro-intestinal hormone.
It is secreted by the mucosa of the small intestine,specifically the duodenum.
Its primary function is to stimulate the gallbladder to contract and release bile,and to stimulate the pancreas to secrete digestive enzymes.

(A) $Pepsin$ is a proteolytic enzyme secreted by the gastric glands located in the stomach wall. It acts on proteins, specifically converting $casein$ (a milk protein) into $paracasein$ or proteoses and peptones. Therefore, the set $Pepsin - \text{stomach wall} - \text{casein}$ is correct.

(A) Salivary amylase is an enzyme found in saliva that begins the chemical digestion of starch into simpler sugars like maltose and dextrin.
It is commonly referred to as $Ptyalin$.

(B) Starch is a polysaccharide composed of glucose units.
Amylase is an enzyme that catalyzes the hydrolysis of starch into sugars.
Specifically,salivary amylase and pancreatic amylase break down starch into maltose,a disaccharide.
Therefore,the correct enzyme responsible for this conversion is amylase.

(D) $Enterogastrone$ is a hormone secreted by the duodenal epithelium.
It acts to inhibit gastric secretion and gastric motility when chyme enters the duodenum,thereby regulating the digestive process.

(C) The well-established gastrointestinal hormones are:
$i$. Secretin
$ii$. Cholecystokinin $(CCK)$
$iii$. Gastrin
$iv$. Gastric Inhibitory Peptide $(GIP)$
$v$. Motilin
Among the given options,Secretin is a primary hormone secreted by the duodenal mucosa that stimulates the pancreas to release bicarbonate-rich pancreatic juice.

(C) The correct answer is $Enterocrinin$.
$Enterocrinin$ is a hormone secreted by the epithelium of the entire small intestine.
Its primary function is to stimulate the $Crypts$ $of$ $Lieberkuhn$ to release enzymes into the intestinal juice,thereby acting as an activator for the secretion of intestinal juice.

(B) Trypsinogen is an inactive enzyme (zymogen) secreted by the pancreas into the small intestine.
It is converted into its active form,trypsin,by an enzyme called enterokinase (also known as enteropeptidase).
Enterokinase is secreted by the intestinal mucosa.
Therefore,the correct option is $B$.

(C) Secretin is a peptide hormone produced by the $S$-cells of the duodenum,which is a part of the small intestine.
It is released into the bloodstream in response to the acidic chyme entering the duodenum from the stomach.
Its primary function is to stimulate the pancreas to secrete a bicarbonate-rich fluid,which helps neutralize the acidity of the chyme in the small intestine.

(B) The hormone $Secretin$ is secreted by the $S$-cells located in the mucosal lining of the $Duodenum$.
It is released in response to the low $pH$ (acidity) of the chyme entering the small intestine from the stomach.
$Secretin$ stimulates the pancreas to secrete water and bicarbonate ions into the small intestine to neutralize the acidic chyme.

(A) The hormone $Gastrin$ is a polypeptide hormone secreted by the $G$-cells located in the pyloric region of the stomach wall.
It is released into the bloodstream and acts on the gastric glands.
Its primary function is to stimulate the parietal cells (also known as oxyntic cells) of the stomach to secrete $HCl$ and pepsinogen,which are essential for the digestion of food.

(C) The discharge of pancreatic juice is primarily regulated by two hormones: $Secretin$ and $Cholecystokinin$ $(CCK)$.
$Secretin$ acts on the exocrine pancreas to stimulate the secretion of water and bicarbonate ions.
$Cholecystokinin$ $(CCK)$ acts on the pancreas to stimulate the secretion of pancreatic enzymes.
Since both are involved,and $Secretin$ is often cited as the primary hormone for the aqueous component (pancreatic juice volume),in many contexts,both are correct. However,$Secretin$ is the classic answer for the stimulation of pancreatic juice secretion.