Digestion and absorption Sample paper

Q1. Name the hormone which stimulates the secretion of gastric juice. 

  • 1) Renin
  • 2) Enterogastrone
  • 3) Enterokinase
  • 4) Gastrin

Solution

The hormone which stimulates the secretion of gastric juice is gastrin. It is secreted by the parietal cells of the stomach and aids in gastric motility.

Q2. The enzyme pepsin acts in  

  • 1) Acidic medium in the pancreas  
  • 2) Intestine  
  • 3) Mouth  
  • 4) Acidic medium in stomach  

Solution

Pepsin hydrolyses proteins into short polypeptides in an acidic medium of pH 2.0 in the stomach.  

Q3. Vitamin K is required for

  • 1) Change of prothrombin to thrombin
  • 2) Change of fibrinogen to fibrin
  • 3) Synthesis of prothrombin
  • 4) Formation of thromboplastin

Solution

Vitamin K is essential for the formation of prothrombin from liver cells and helps in blood coagulation. Vitamin K is also known as antihaemorrhagic factor or phylloquinone.

Q4. How many teeth appear twice during the lifespan of an individual?   

  • 1) 20  
  • 2) 22  
  • 3) 32  
  • 4) 16  

Solution

The teeth which appear twice during the lifespan are the milk teeth (8 incisors, 4 canines and 8 molars) which are temporary and erupt when the child is about 6 months old. They again appear by the end of 24 months.  

Q5. Bile contribution to digestion is   

  • 1) Emulsification of dietary fats  
  • 2) Carbohydrate digestion  
  • 3) Nucleic acid meta bolism  
  • 4) Phagocytosis  

Solution

The liver secretes bile which is stored in the gall bladder. Bile salts help in the digestion of fats in the small intestine which converts large fat droplets into small ones. This process is called emulsification.  

Q6. Name the gland present in the lower jaw.

Solution

Sub-maxillary gland

Q7. Name the movements which help to pass the food down through the oesophagus.

Solution

Peristalsis

Q8. Bile salts act as an activator of which enzyme?   

  • 1) Lipase  
  • 2) Pancreatic lipase  
  • 3) Pepsinogen  
  • 4) Trypsinogen  

Solution

Bile contains no enzyme, but it activates the enzyme lipase.  

Q9. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?   

  • 1) Exonuclease  
  • 2) Protease  
  • 3) Lipase  
  • 4) Endonuclease  

Solution

The groups of enzymes which catalyse the hydrolysis of phosphodiester bonds between nucleic acids in a polynucleotide chain are endonucleases.  

Q10. Peptic cells secrete 

  • 1) Gastrin
  • 2) Cholecystokinin
  • 3) HCl
  • 4) Pepsin

Solution

Peptic cells of the gastric glands secrete digestive enzymes such as pepsin and lipase.

Q11. Which one of the following pairs is not correctly matched?  

  • 1) Vitamin B12 – Pernicious anaemia  
  • 2) Vitamin B2 – Pellagra  
  • 3) Vitamin B1 – Beri-beri  
  • 4) Vitamin B6 – Loss of appetite  

Solution

Vitamin B2 helps in RBC production. Its deficiency causes cheilosis.  

Q12. Name the region of the large intestine where symbiotic microorganisms take their shelter.

Solution

Caecum

Q13. Name the enzyme secreted by the peptic cells.

Solution

Pepsinogen

Q14. Pellagra is caused by the deficiency of

  • 1) Pyridoxine
  • 2) Biotin
  • 3) Niacin
  • 4) Folic acid

Solution

A disease called pellagra is caused by deficiency of Vitamin B3.

Q15. Explain the role of the buccal cavity during digestion.

Solution

The buccal cavity performs mastication of food and facilitates swallowing. The teeth and tongue mix the food thoroughly with saliva. The mucus present in the saliva helps in lubricating food, and it also adheres masticated food particles together into a bolus. The bolus is then swallowed and conveyed into the pharynx.

Q16. Name the layer which forms the serosa.

Solution

Mesothelium

Q17. Carbohydrate digestion first occurs in the

  • 1) Mouth
  • 2) None of the above
  • 3) Stomach
  • 4) Intestine

Solution

Carbohydrate digestion starts in the oral cavity, in which the food is mixed with saliva which then moves into the stomach.

Q18. Oxyntic cells secrete   

  • 1) NaOH  
  • 2) Trypsin  
  • 3) Pepsin  
  • 4) HCl  

Solution

Oxyntic cells (also called parietal cells) lie against the basement membrane and secrete hydrochloric acid.  

Q19. ‘Crypts of Lieberkühn’ are found in

  • 1) Intestine
  • 2) Liver
  • 3) Gall bladder
  • 4) Pancreas

Solution

The ‘Crypts of Lieberkühn’ (also known as the intestinal glands) are glands found in the walls of the small intestine. The crypts which are embedded within the epithelial lining secrete various enzymes, including sucrase and maltase.

Q20. Stool of a person contains whitish grey colour due to malfunction of which type of organ?  

  • 1) Pancreas  
  • 2) Spleen  
  • 3) Kidney  
  • 4) Liver  

Solution

Bilirubin is broken down to urobilinogen and stercobilinogen. The yellowish brown colour of stool is due to stercobilinogen. Due to the malfunctioning of liver, insufficient production of stercobilinogen leads to white stool.  

Q21. The richest sources of Vitamin B12 are

  • 1) Carrot and chicken’s breast
  • 2) Goat’s liver and Spirulina
  • 3) Rice and hen’s egg
  • 4) Chocolate and green gram

Solution

Vitamin B12 is the only vitamin which is not found in vegetables. It is present in animal protein such as meat, liver, fish and Spirulina. It promotes DNA synthesis, maturation of RBCs and myelin formation.

Q22. Anxiety and eating spicy food together in an otherwise normal human may lead to 

  • 1) Vomiting
  • 2) Jaundice
  • 3) Indigestion
  • 4) Diarrhoea

Solution

Anxiety and eating spicy food together in an otherwise normal human may lead to indigestion.

Q23. In humans, sphincter of Oddi is associated with the opening of  

  • 1) Hepatopancreatic ampulla  
  • 2) Common hepatic duct  
  • 3) Pyloric stomach  
  • 4) Oesophagus  

Solution

The sphincter of ampulla or sphincter of Oddi is a muscular valve which controls the flow of digestive juices (bile and pancreatic juice) through the hepatopancreatic ampulla into the second part of the duodenum.  

Q24. ‘Glisson’s capsule’ is associated with  

  • 1) Pancreas  
  • 2) Lung  
  • 3) Liver  
  • 4) Kidney  

Solution

‘Glisson’s capsule’ is the capsule of the liver. It is a layer of connective tissue surrounding the liver and enclosing the hepatic artery, portal vein and bile ducts within the liver.  

Q25. Chief cells of the gastric glands are   

  • 1) Compound tubular  
  • 2) Simple tubular  
  • 3) Branched tubular  
  • 4) Coiled tubular  

Solution

Gastric glands are numerous microscopic, tubular glands formed by the epithelium of the stomach.  

Q26. Digestive enzymes are 

  • 1) Lyases
  • 2) Transferases
  • 3) Hydrolases
  • 4) Oxidoreductases

Solution

Any enzyme which uses hydrolysis (breaking a molecule in two, resulting in two smaller molecules) is called a hydrolase. In chemical digestion, hydrolysis is the main chemical reaction used by the enzymes to break proteins, lipids, carbohydrates and other complex molecules into smaller pieces.

Q27. The pancreas produces  

  • 1) Three digestive enzymes and two hormones  
  • 2) Three digestive enzymes and one hormone  
  • 3) Three digestive enzymes and no hormone  
  • 4) Two digestive enzymes and one hormone  

Solution

The pancreas produces pancreatic juice which contains trypsinogen, chymotrypsin, carboxypeptidase, lipase, pancreatic alpha amylase, elastase and nucleases. Of these, the first three are concerned with protein digestion which converts proteins into small peptides.     Other than these, the pancreas also secretes the hormones insulin and glucagon which act antagonistically in controlling the blood sugar level.  

Q28. Argentaffin cells in human beings are found in   

  • 1) Stomach  
  • 2) Liver  
  • 3) Large intestine  
  • 4) Small intestine  

Solution

Argentaffin cells, the round or partly flattened cells, occur in the tissue lining the stomach and contain granules thought to have a secretory function.  

Q29. What are partially hydrolysed proteins called?

Solution

Peptones

Q30. The gastric juice contains 

  • 1) Pepsin, Amylase, Trypsin
  • 2) Trypsin, Pepsin, Lipase
  • 3) Trypsin, Pepsin, Rennin
  • 4) Pepsin, Lipase, Rennin

Solution

Gastric juice is secreted by gastric glands which also secrete digestive enzymes such as pepsin and rennin. The gastric glands also produce a small amount of gastric amylase and gastric lipase.

Q31. What will happen if the secretion of the parietal cells of the gastric glands is blocked within an inhibitor?  

  • 1) Gastric juice will lack pepsinogen.  
  • 2) Enterokinase will not be released from duodenal mucosa, so trypsinogen is not converted to trypsin.  
  • 3) In the absence of HCl secretion, inactive pepsinogen is not converted into active enzyme pepsin.  
  • 4) Gastric juice will lack chymosin.  

Solution

Gastric glands are numerous microscopic tubular glands formed by the epithelium of the stomach. The parietal cells are large and most numerous on the side walls of gastric glands. They secrete hydrochloric acid and Castle’s intrinsic factor. The peptic cells of gastric glands secrete gastric digestive enzymes as proenzymes (pepsinogen and prorennin) and a small amount of gastric amylase and gastric lipase. The hydrochloric acid maintains a strongly acidic pH of about 1.5 to 2.5 in the stomach.  

Q32. Where do you find the sphincter of Oddi?

Solution

The sphincter of Oddi is situated between the opening of the hepatopancreatic duct and the duodenum.

Q33. State the action of the following enzymes and the resulting end-product: Carboxypeptidase Sucrase Nucleosidases Amylase

Solution

Carboxypeptidase – It acts on proteins, peptones and proteoses. The end-product is dipeptides. Sucrase – Sucrase acts on sucrose, and the end-products are glucose and fructose. Nucleosidases – These enzymes act on nucleosides, and the end-products are sugars and nitrogen bases. Amylase – It acts on starch, and the end-product is disaccharides.

Q34. Where is the liver situated in the body? Name the structural and functional units of the liver.

Solution

The liver is situated in the abdominal cavity just below the diaphragm. Hepatic lobules are the structural and functional units of the liver.

Q35. What kinds of muscles are present in the muscularis layer of the alimentary canal?

Solution

Smooth muscles

Q36. Which one of the following is a matching pair of a substrate and its particular digestive enzyme?  

  • 1) Starch – Steapsin  
  • 2) Casein – Chymotrypsin  
  • 3) Maltose – Maltase  
  • 4) Lactose – Rennin  

Solution

Intestinal juices contain several oligosaccharides which hydrolyse specific polysaccharides into their monosaccharides. Maltase is one of them, which hydrolyses maltose into two glucose molecules.  

Q37. Name the enzymes present in the saliva.

Solution

Salivary amylase and lysozyme

Q38. What is the technical term used for temporary milk teeth?

Solution

Deciduous teeth

Q39. Calcium deficiency occurs in the absence of vitamin

  • 1) B
  • 2) C
  • 3) E
  • 4) D

Solution

Vitamin D mainly helps in the Ca/P balance of body fluids. It increases absorption of calcium from the intestines, so it is necessary for formation of healthy bones and teeth. Deficiency of Vitamin D causes an increased loss of calcium ions in urine; thus, calcium ions get deposited in the bones. This causes rickets in children and osteomalacia in pregnant woman.

Q40. What is the technical term for swallowing food?

Solution

Deglutition

Q41. Which of the following is the largest gland in an adult man? 

  • 1) Pancreas
  • 2) Thyroid
  • 3) Liver
  • 4) Thymus

Solution

The liver is the largest glandular organ in the body and performs many vital functions to keep the body pure of toxins and harmful substances. It is a vital organ which supports nearly every organ in the body in some way. Without a healthy liver, a person cannot survive. An average adult liver weighs about three pounds.

Q42. Name the capsule which covers the hepatic lobule.

Solution

Glisson’s capsule

Q43. When breastfeeding is replaced by less nutritive food low in proteins and calories in infants below the age of one year, they are likely to suffer from  

  • 1) Marasmus  
  • 2) Pellagra  
  • 3) Rickets  
  • 4) Kwashiorkor  

Solution

Prolonged starvation causes marasmus due to a generalised wasting of body because of both energy and protein deficiency. The body becomes lean and weak, the eyes are depressed and the skin is wrinkled.  

Q44. Which of the following is a fat-soluble vitamin and its related deficiency disease?   

  • 1) Retinol – Xerophthalmia  
  • 2) Cobalamin – Beri-beri  
  • 3) Ascorbic acid – Scurvy  
  • 4) Calciferol – Pellagra  

Solution

Vitamin A (retinol) and Vitamin D (calciferol) are fat-soluble vitamins, but the deficiency of calciferol causes rickets and osteomalacia.     Xerophthalmia is caused by deficiency of Vitamin A.  

Q45. Name teeth found in an adult human.

Solution

Incisors, canines, molars and premolars.

Q46. What is assimilation?

Solution

Assimilation is the use of absorbed food or nutrients by the tissues.

Q47. Name the enzyme which gets activated due to enterokinase.

Solution

Trypsinogen

Q48. Name three secretions released into the small intestine.

Solution

Bile, pancreatic juice and intestinal juice

Q49. Bile secretion is proportional to the concentration of 

  • 1) Carbohydrates
  • 2) None of the above
  • 3) Fats
  • 4) Proteins

Solution

The liver secretes bile which is stored in the gall bladder. Bile salts help in the digestion of fats in the small intestine which converts large fat droplets into small ones.

Q50. The crown of teeth is covered by 

  • 1) Enamel
  • 2) Dentine
  • 3) None of the above
  • 4) Both 1 and 2 above

Solution

Of the three regions of the teeth, the part which projects above the gums is the crown which is covered by enamel, the hardest substance of the human body.

Q51. Name the two ducts which form the bile duct.

Solution

The cystic duct and the hepatic duct join to form the common bile duct.

Q52. Explain diphyodont dentition.

Solution

Dentition in which animals exhibit two kinds of teeth in their life – first deciduous teeth and second adult teeth – is called diphyodont dentition.

Q53. Name the duct which releases bile and pancreatic juice. Where are these juices released? Name the inactive enzymes present in the pancreatic juices.  

Solution

The hepatopancreatic duct releases bile and pancreatic juice. These juices are released into the small intestine. The enzymes present in the pancreatic juices are trypsinogen, chymotrypsinogen, procarboxypeptidases, amylases, lipases, nucleases etc.  

Q54. Pepsinogen is secreted by   

  • 1) Parietal cell  
  • 2) Mast cell  
  • 3) Chief cell  
  • 4) Oxyntic cell  

Solution

Pepsinogen and prorennin are gastric digestive enzymes secreted by the chief cells or peptic cells of the gastric glands.  

Q55. State the role of the large intestine.

Solution

Role of the large intestine: Water is absorbed in the large intestine, and drugs and minerals are also absorbed to some extent. The large intestine secretes mucus which helps in adhering undigested particles together and lubricates them for an easy passage outside the body.

Q56. Secretin and cholecystokinin are digestive hormones. These are secreted by 

  • 1) Duodenum
  • 2) Ileum
  • 3) Pyloric stomach
  • 4) Oesophagus

Solution

Secretin and cholecystokinin are two main gastrointestinal hormones secreted in the duodenum of the alimentary canal. Cholecystokinin stimulates gall bladder contraction and thus increases the flow of bile salts into the intestine. Secretin stimulates the release of an alkaline pancreatic fluid which neutralises stomach acid as it enters the intestine.

Q57. Why are humans called thecodonts?

Solution

In humans, teeth are embedded in the sockets of the jaw bone, and such type of attachment is called thecodont. Hence, humans are called thecodonts.

Q58. In man, the zymogen or chief cells are mainly found in

  • 1) Pyloric part of stomach
  • 2) Fundic part of stomach
  • 3) Duodenum
  • 4) Cardiac part of stomach

Solution

Chief cells or zymogen are mainly found in the fundic part of the stomach.

Q59. Name the ions present in the saliva.  

Solution

The ions present in saliva are Na+, K+, Cl and HCO3.  

Q60. Why are humans called heterodonts?

Solution

Human beings show the presence of four types of teeth, i.e. canines, incisors, molars and premolars. Hence, they are called heterodonts.

Q61. Kwashiorkor disease occurs due to deficiency of

  • 1) Hormones
  • 2) Fats
  • 3) Proteins
  • 4) Sugars

Solution

Kwashiorkor is caused by deficiency of protein in the diet.

Q62. State the optimum pH required for the action of salivary amylase on carbohydrates.

Solution

The optimum pH for the action of salivary amylase on carbohydrates is 6.8.

Q63. Name various substances present in bile. State the functions of bile.

Solution

Various substances present in bile are bilirubin, biliverdin, bile salts, cholesterol and phospholipids. Bile helps in breaking down of the fats into small micelles, and this process is called emulsification. Bile also helps in activation of lipases.

Q64. State the term used for the protein-coated fat droplets.

Solution

Chylomicrons

Q65. Name various substances present in bile. State the functions of bile.

Solution

Various substances present in bile are bilirubin, biliverdin, bile salts, cholesterol and phospholipids. Bile helps in breaking down of the fats into small micelles, and this process is called emulsification. Bile also helps in activation of lipases.

Q66. Name the three types of cells present in the gastric glands of the stomach, and also state their secretions. Also state the significance of the secretions.  

Solution

The three types of cells found in gastric glands and their secretions are     Mucus neck cells secrete mucus. Mucus provides lubrication and protection to the mucosal epithelium from the excoriating effect of HCl.   Peptic or chief cells secrete pepsinogen. Pepsinogen converts proteins into proteoses which are further converted into peptones.   Oxyntic cells or parietal cells which secrete HCl and intrinsic factors. HCl provides acidic pH 1.8 which is necessary for the action of pepsins. Intrinsic factors are required for the absorption of vitamin B12.

Q67. For a person suffering from high blood cholesterol, the physicians recommend  

  • 1) Vanaspati margarine  
  • 2) Vegetable oil such as groundnut oil  
  • 3) Red meat with layers of fats  
  • 4) Pure ‘desi ghee’ or butter  

Solution

A high intake of saturated fat causes high blood cholesterol which ultimately gets deposited in the walls of the arteries causing their blockage resulting in various cardiac diseases. Ghee, butter, red meat and vanaspati are rich sources of saturated fats. A patient with high blood cholesterol is suggested to consume unsaturated fats as vegetable oils.  

Q68. What is the optimal pH for pepsin in the stomach?

Solution

1.8 is the optimal pH for pepsins.

Q69. What is the function of the gastro-oesophageal sphincter?  

Solution

The gastro-oesophageal sphincter regulates the opening of the oesophagus into the stomach.  

Q70. State the role of lysozyme present in the saliva.

Solution

Lysozyme acts as an anti-bacterial agent and prevents infections.

Q71. What is diarrhoea? Why do skin and eyes turn yellow in jaundice?

Solution

Diarrhoea is the abnormal frequency of bowel movement which increases the liquidity of the faecal discharge. In jaundice, due to the deposition of bile, the skin and eyes turn yellow.

Q72. State the four layers of the walls of the alimentary canal.  

Solution

The four layers of the walls of the alimentary canal are     Outermost serosa made of mesothelium.   Middle muscularis formed of smooth muscles arranged in inner circular and outer longitudinal layers.   The inner mucosal layer formed of the loose connective tissue containing nerves, blood vessels and lymph vessels.   The innermost layer is the sub-mucosal layer which lines the lumen and consists of rugae and villi.  

Q73. State the common name given to the secretions of the intestinal mucosa and the secretions of the goblets cells.

Solution

Succus entericus

Q74. Name the bile pigments present in bile.

Solution

Bilirubin and biliverdin

Q75. Name the lymph vessel which joins villi.  

Solution

Lacteal vessel  

Q76. Where are the pyloric sphincters present?

Solution

Pyloric sphincters are present between the stomach and the small intestine.

Q77. Name the point of attachment between the tongue and the oral cavity.  

Solution

Frenulum  

Q78. Name the valve which prevents the backflow of the faeces into the large intestine.  

Solution

Ileocaecal valve  

Q79. Name the enzyme which digests milk proteins in infants.

Solution

Rennin

Q80. Name the cells which secrete HCl in the stomach.

Solution

Oxyntic cells

Q81. Write any two causes of indigestion.

Solution

Inadequate enzyme secretion and anxiety

Q82. In which region of the small intestine are the simple substances absorbed in blood?

Solution

Jejunum and ileum