Digestion & Absorption Test 6

The production of biliverdin from heme is the first major step in the catabolic pathway, after which the enzyme biliverdin reductase performs the second step, producing bilirubin from biliverdin. Bilirubin is excreted in bile and urine, and elevated levels may indicate certain diseases.

Ruminants like cows and sheep contain certain symbiotic anaerobic bacteria (such as Cellulomonas and Ruminococcus spp.) in the caecum, and these bacteria produce enzymes called cellulases that help the microorganism to digest cellulose and they also contain Ruminococcus albus, and Ruminococcus flavefaciens are the principle cellulose degrading organisms.

In cow's milk, approximately 82% of milk protein is casein and the remaining 18% is serum, or whey protein. The casein family of protein consists of several types of caseins (α-s1, α-s2 , ß, and 6) and each has its own amino acid composition, genetic variations, and functional properties.

Amylase is a digestive enzyme that acts on starch in food, breaking it down into smaller carbohydrate molecules. The enzyme is made in two places. 
First, salivary glands in your mouth make salivary amylase, which begins the digestive process by breaking down starch when you chew your food, converting it into maltose, a smaller carbohydrate.
Cells in your pancreas make another type of amylase, called pancreatic amylase, which passes through a duct to reach your small intestine. Pancreatic amylase completes digestion of carbohydrate. Hence, the amylase enzyme acts on the starch.
So, the correct answer is 'starch'.

The sugar present in the sugarcane is known as sucrose. It is a disaccharide which is formed by the glycosidic linkage of first carbon of the glucose and second carbon of the fructose. The molecular formula of sucrose is C₁₂​H₂₂​O₁₁​. On hydrolysis, the glycosidic linkage breaks and the sucrose is converted into simple sugars.

Hindgut fermentation is a digestive process seen in monogastric herbivores, animals with a simple, single-chambered stomach. Cellulose is digested with the aid of symbiotic bacteria. The microbial fermentation occurs in the digestive organs that follow the small intestine: the large intestine and caecum.

The liver cells secrete about 800 to 1,000 ml of bile, which contains bile salts needed for the digestion of fats in the diet.

Peristalsis is the series of involuntary movements in the digestive tract. It is characterized by waves of alternate circular contraction and relaxation of the longitudinal smooth muscle of tube by which the contents are propelled onward. Medulla is responsible for the peristaltic movement of food. Muscle contraction also mixes food with the digestive juices. They also act as valves preventing back flow in the tract. The control allows time for digestion and absorption to take place. The rectum is a slightly dilated section of the colon about 13 cm long. It leads from the sigmoid colon and terminates in the anal canal. The large intestine does not exhibit peristaltic movement as it is seen in other parts of the digestive tract.

Rennin is a proteolytic enzyme found in gastric juice of infants which helps in the digestion of milk proteins. Its action on milk is called curdling of milk. Rennin is secreted as pro rennin, which changes into active rennin in the presence of HCl. Rennin curdle milk protein caseinogens, which is hydrolysed into casein. It converts casein into solid calcium paracaseinate in presence of Ca²⁺. 

Invertase is an enzyme, that catalyzes the hydrolysis (breakdown) of sucrose. The resulting mixture of fructose and glucose is called inverted sugar syrup. Sucrase is also called invertase. Invertase hydrolyze sucrose to give the same mixture of glucose and fructose.

Small intestine are the principal organ for absorption of nutrients. The digestion is completed here and the final products of digestion such as glucose, fructose, fatty acids, glycerol and amino acids are absorbed through the mucosa into the blood stream and lymph. Absorption is the process by which the end products of digestion pass through the intestinal mucosa (blood capillaries of villi) into the blood or lymph. It is carried out by passive, active or facilitated transport mechanisms.

Digestion of starch begins with the action of salivary alpha-amylase/ptyalin, although its activity is slight in comparison with that of pancreatic amylase in the small intestine.The action of the salivary amylase is inhibited by the acidic pH of the stomach.

Once a protein source reaches your stomach, hydrochloric acid, and enzymes called proteases to break it down into smaller chains of amino acids. Amino acids are joined together by peptides, which are broken by proteases. Hence, Proteins are broken down into amino acids completely in Intestine.

Starvation mode is a state in which the body is responding to prolonged periods of low energy intake levels. The body responds to reduced energy intake by burning fat reserves and consuming muscle and other tissues. Specifically, the body burns fat after first exhausting the contents of the digestive tract along with glycogen reserves stored in muscle and liver cells. After prolonged periods of starvation, the body will utilize the proteins within muscle tissue as a fuel source. 

Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down or emulsify fats into fatty acids, which can be taken into the body by the digestive tract. Bile contains mostly cholesterol, bile acids (also called bile salts), and bilirubin (a breakdown product of red blood cells). It also contains water, body salts (such as potassium and sodium), copper and other metals. Bile does not function in digest fat by enzymatic action, eliminate waste product or regulate process of digestion.

Proteolytic enzymes are those which help break down and digest proteins. They are essential for cell division, immune function, and protein recycling. Trypsin, Erepsin, and pepsin are the essential proteolytic enzymes. These enzymes help to break down protein in meat, eggs, and fish into simpler amino acids.
So, the correct answer is Trypsin, Erepsin, pepsin.

The Brunner's glands are branched tubular glands and. They secrete alkaline watery fluid, a little enzyme, and mucus. They open into the crypts of Lieberkuhn. The mixture of secretions is called Intestinal juice, or succus entericus.

Chymotrypsin is a proteolytic enzyme (serine protease) acting in the digestive systems of many organisms. It facilitates the cleavage of peptide bonds by a hydrolysis reaction, which despite being thermodynamically favorable, occurs extremely slowly in the absence of a catalyst.

Secretion and synthesis of bile is the main function of liver. Bile is yellowish-green, alkaline fluid. In bile juice, bile salts, sodium carbonate, glycolate, taurocholate, bile pigments, cholesterol, lecithin etc. are present. Bile salts help in emulsification of fats in small intestine. It mainly act at the duodenum part of the small intestine.

Urea cycle in liver helps in conversion of excess of amino acids into urea. It takes place in five major steps. The extra proteins in the body are degraded by the process of deamination where the NH2​ group is removed and it is converted into ammonium ions in the liver. The ammonium ions enter urea cycle and get converted into urea. The urea formed in liver is transported to kidney through circulation and finally gets excreted. So, the correct answer is "liver".

Option ( b) intestine and stimulate pancreatic glands  is correct answer. 

Explanation :- 

Secretin is a hormone that regulates water hemostasis,  Throughout the body & by regulating secretion in stomach, pancreas & liver. It is a peptide hormone produced in the S-Cells of duodenum, which are located in intestinal glands. Hence, secretin hormone is produced in the intestine & stimulates Pancreatic glands.

Rennin is a milk protein digesting enzyme found in gastric juice of stomach in infants.

Digestion and absorbtion primarily occurs in Small intestine because in inner surface of small intestine Millon's of tiny finger like projection present collectively know as Villi which help in digestion and absorbtion.

Bile juice has bile pigments such as bilirubin and biliverdin. These break down large fat globules into smaller globules so that the pancreatic enzymes can easily act on them. This process is known as emulsification of fats. The pancreatic juice contains enzymes that complete the digestion of starch called pancreatic amylase. It also contains pancreatic enzymes that complete the digestion of protein called trypsin, chymotrypsin and carboxypeptidase. Hence pancreatic juice plays a vital role in the digestion of proteins.

Trypsin is produced in the pancreas as the inactive proenzyme trypsinogen. In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides.