31 Years NEET Previous Year Questions: Digestion & Absorption - 1 (Old NCERT) - NEET MCQ

The secretions of the brush border cells of the mucosa alongwith the secretions of the goblet cells constitute the intestinal juice or succus entericus.

(a) Small intestine is distinguishable into three regions, a ‘U’ shaped duodenum, a long coiled middle portion jejunum and a highly coiled ileum.
(b) A narrow finger-like tubular projection, the vermiform appendix which is a vestigial organ, arises from the caecum.
(c) Ileum opens into the large intestine.
(d) The wall of alimentary canal possesses four layers from outer to inner namely serosa, muscularis, submucosa and mucosa. Serosa is the outermost layer and mucosa is the innermost layer.

• The majority of mammals, including human beings, erupt two sets of teeth during their lifetime, a set of temporary milk or deciduous teeth that is replaced by a set of permanent or adult teeth. This type of dentition is called diphyodont. 
• An adult human has 32 permanent teeth which are of four different types (heterodont dentition), namely, incisors (1), canines (C), premolars (PM), and molars (M). Teeth are embedded in the sockets of the jawbones, which represents the codont dentition.

Paneth cells, present in the bottom of crypts of Lieberkuhn, are rich in zinc and contain acidophilic granules. There is evidence that these cells secrete antibacterial lysozyme. Zymogen cells or peptic cells are present in the stomach and secrete pepsinogen. 

Kupffer cells are present in the liver. They are phagocytic in nature and engulf disease-causing microorganisms, dead cells, etc. Argentaffin cells, found in crypts of Lieberkuhn, synthesize hormone secretin and 5 - hydroxytryptamine.

Cholecystokinin pancreozymins (CCKPZ) is a hormone secreted from the small intestine. It stimulates the gall bladder to release bile and the pancreas to secrete and release digestive enzymes in the pancreatic juice. Hormone secretin is secreted from the duodenum and releases bicarbonates in the pancreatic juice. It also increases the secretion of bile and decreases gastric secretion and motility.

Pancreatic juice secretion is principally regulated by the hormones secretin and cholecystokinin, which are produced by the walls of the duodenum, and by the action of autonomic innervation. The release of these hormones into the blood is stimulated by the entry of the acidic chyme into the duodenum.

Deficiency of vitamin B₁ causes Beri Beri disease. Beri Beri disease was discovered by Eijkman in 1897. Eijkman observed that the disease beri beri occuried mainly in people subsisting on a polished rice diet. This disease is rare in the western world because of food habits and food enrichment. Beri beri disease is characterized by loss of apetite and weight and vigour, retarted growth, degeneration of nerves, muscle atrophy, even paralysis, weakened heart beat and failure.

A child may have a diet containing sufficient carbohydrates and fats but still suffers a serious form of malnutrition. This form of malnutrition is known as Kwashiorkar. It develops in children whose diets are deficient in protein. When the first child is weaned (accustomed to food other than its mother’s milk) after the second is born, its primary supply of protein (the mother’s milk) is lost. If the new diet is very low in protein to meet the needs of the growing individual this disease develops.
All the food stuff eg. milks, lentils, meat and eggs are rich in proteins. 

Presence of microvilli on the epithelial cells of intestine increases  the surface area for absorption of food. 

Secretin and cholecystokinin are secreted in the duodenum.
Stimulus to
(i) Secretin : Acidic chyme entry into duodenum
(ii) CCK-PZ : Presence of fat in duodenum Action (i) Secretin : Releases bicarbonates in the pancreatic juice.
(ii) CCKPZ : contracts the gall bladder to release bile. Stimulating pancreas to secrete and release digestive enzymes in the pancreatic juice.

Angiotensinogen is a protein secreted by liver cells.

Due to a long hunger strike and survival on water, a person will have less urea in his urine because urea comes to kidney as a waste product from liver which is formed after the breakdown of protein fat, carbohydrate during hunger.  It is not synthesised but the synthesised ones are catabolised. 

Retinol, also known as Vitamin A, is a fat-soluble vitamin that is important for vision, immune function, and cell growth and differentiation. Its deficiency can lead to a condition called xerophthalmia, which is characterized by dry eyes, night blindness, and ultimately, blindness.

Option 2 is incorrect because cobalamin (Vitamin B12) deficiency can lead to megaloblastic anemia, but not beriberi, which is caused by thiamine (Vitamin B1) deficiency.

Option 3 is incorrect because calciferol (Vitamin D) deficiency can lead to rickets in children and osteomalacia in adults, but not pellagra, which is caused by niacin (Vitamin B3) deficiency.

Option 4 is also incorrect because ascorbic acid (Vitamin C) deficiency can lead to scurvy, but it is a water-soluble vitamin, not a fat-soluble one.

If the secretion of parietal cells of gastric glands is blocked with an inhibitor, in the absence of HCI secretion, inactive pepsinogen is not converted into the active enzyme pepsin. 

Small intestine- Starch disaccharide  (maltose) Small intestine is the portion of the alimentary canal between the stomach and large intestine. It is subdivided into the duodenum, jejunum, and ileum. It plays an essential role in the final digestion and absorption of food. 

Modern detergent contain enzymes preparations of alkaliphiles. Alkaliphiles live in alkaline environments like soda lakes, or alkaline soil. The pH level in alkaline substances is from about 9 to 11 on the pH scale. The alkaliphiles keep an alkaline level of about 9 pH inside the cells, but the environment has a higher level of alkalinity. Alkaliphiles can keep the right pH level by pumping in hydrogen ions in out at the right rate. 

If breast feeding is replaced by less nutritive food low in proteins and calories; the infants below the age of (one year are likely to suffer from Marasmus.
Marasmus is a form of malnutrition that occurs when there is not enough protein in the diet.This disease is more common in very poor countries. It often occurs during a drought or other natural disaster, or during political unrest. These conditions are responsible for a lack of food, which leads to malnutrition.

Young infant may be feeding entirely on mother’s milk which is white in colour but the stools which the infant passes out is quite yellowish because bile pigments passed through bile juice. Bile pigments are any of several coloured compounds derived from porphyrin that are found in bile; principally bilirubin and biliverdin. Bile pigment is produced regularly when old red blood cells are broken down, mainly by the spleen. In some blood-disorders where the red cells are destroyed, more bile pigment is produced.

Fructose and amino acids are absorbed through intestinal mucosa with the help of carrier ions like Na+.Carbohydrates are absorbed as monosaccharides (simple sugars such as glucose, fructose, and galactose that cannot be further broken down by hydrolysis) or as disaccharides carbohydrates (such as sucrose, lactose, maltose, and dextrin that can be hydrolyzed to two monosaccharides). These simpler molecules, however, must be obtained by the breaking down of polysaccharides, complex carbohydrates that contain many monosaccharides.
Chief among these is amylase, a starch that accounts for 20 percent of dietary carbohydrate.

Fat and cellulose is the pair of food components in human reaches the stomach totally undigested.

Goblet cells, found in the intestinal mucosal epithelium, secrete mucus. The mucus lubricates the food for an easy passage. So, if for some reason, goblet cells become non-functional, it will adversely affect the smooth movement of food down the intestine.

The coughing would have been due to improper movement of epiglottis.

In humans milk protein digesting enzyme in stomach is pepsin. In calves it is rennin. Rennin is also present in small amounts in human infants but not adults. Pepsin acts on water soluble caseinogen (milk protein) to form solubles 'casein'. This combines with calcium salts to form insoluble calcium paracaseinate, which gets readily digested enzymatically.

Answer is B  "pepsin"

Because it is inactive form and we know that all enzymes of pancreas are secreted in this form. Enzyme enterokinase is secreted from the duodenal mucosa, at the chemical stage that changes the inactive pancreatic secretion trypsinogen to trypsin.

The adult dental formula of human is Incisor   Canine Premolar  Molar

Anxiety and eating spicy food together in normal healthy man can lead to indigestion which is difficulty in digestion.

The caecum is a pouch-like portion of the large intestine which hosts some symbiotic micro-organism. The caecum absorbs water and salts from undigested foods before they continue on to the large intestine.

Small intestine is major area of absorbtion of nutrients. Approximately 80% of absorbtion take place here. Glucose, fructose, fatty acids, amino acids (Glycine etc.) are absorbed through mucosa into blood and lymph by active absorbtion.

Physiological value of carbohydrates is 4.0 kcal/g,
proteins 4.0 kcal/g and of fats is 9.0 kcal/g. Hence,
5 g raw sugar will yield
5 × 4.0 = 20.0 kcal
4 g albumin (protein) will yield
4 × 4.0 = 16.0 kcal
10 + 2 g of fat will yield
12 × 9.0 = 108.0 kcal
Total yield = 144 kcal.

Chemical process of digestion started in the oral cavity by the hydrolytic action of the carbohydrate (potato contains starch) splitting enzyme, the salivary amylase. Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides.