FREE NEET Biology Practice MCQ Test: Digestion And Absorption Exercise 3 Questions Answers With Detailed Explanations [PDF]

Answer: (a)

Answer: (c)

Answer: (b)

Answer: (b)

Bile is stored temporarily in the gall bladder until it is needed by the small intestine to emulsify fats.

Answer: (c)

In small intestine, carbohydrate-digestion is resumed. The food gets mixed with pancreatic juice. It contains the pancreatic amylase (amylopsin) that hydrolyses the polysaccharides into disaccharides.

Answer: (a)

Answer: (a)

Answer: (d)

Oxyntic cells are found on the inner wall of gastric glands and secrete HCl.

Answer: (b)

Answer: (d)

Enterogastrone is secreted by duodenal epithelium and it slows gastric contractions to delay its emptying and also stops secretion of gastric juice. Gastrin stimulates secretion of gastric juice. Cholecystokinin stimulates release of enzymes in pancreatic juice and release of bile from gall bladder. Cholecystokinin is also known as pancreozymin.

Answer: (a)

Anaemia is not a disease. It is a symptom of various diseases which may result from excessive blood loss, excessive blood cell destruction, or decreased blood cell formation. Folic acid is a part of coenzymes for protein and nucleic acid metabolism and is essential for growth and formation of RBCs. Its deficiency leads to anaemia, failure of RBCs to mature and sprue. Vitamin $B_12$ or cyanocobalamin acts as a coenzyme for nucleic acid metabolism and is essential for formation of RBCs and myelin formation. Its deficiency leads to Pernicious (injurious) anaemia and malformation of RBCs.

Answer: (b)

Cholesterol is a fat like material (a sterol) present in the blood and most tissues especially nervous tissue. Cholesterol is synthesized in the body from acetate, mainly in the liver and blood concentration is normally 140-300 mg/100 ml. It can exists as a free sterol or esterified with a long chain fatty acid. High cholesterol is harmful for the body. So, high cholesterol patients are advised to take groundnut oil, margarine and vegetable oils, as these contain polyunsaturated fatty acids that contain less cholesterol in them.

Answer: (c)

The chylomicrons are formed inside enterocytes and are absorbed in lacteals.

Answer: (b)

• Kupffer-cells are phagocytic cells present in liver.
• Zymogen cells are enzyme producing cells which are secreted by pancreas.
• Paneth cell secrete lysozyme which acts as anti-bacterial agent, into the lumen of intestine.
• Argentaffin cells are hormone producing cells.

Answer: (d)

Fat is largely digested in the small intestine. Bile salts of the bile break down fat droplets into many small ones by reducing the surface tension of fat droplets. This process is called emulsification. This increases lipase action on fat.

Answer: (c)

Answer: (c)

The parietal or acid or oxyntic cells of gastric glands secrete HCl (hydrochloric acid). In the presence of HCl, pepsinogen (proenzyme) which is an inactive precursor of pepsin enzyme, gets converted to an active form, i.e., pepsin. The activated pepsin by autocatalysis activates more pepsinogen to pepsin. This pepsin enzyme is the principle protease or proteolytic enzyme of the stomach.

Pepsinogen (Inactive form) $→↖{HCl}$ Pepsin (Active form)

So, in the absence of HCl secretion, inactive pepsinogen is not converted into the active enzyme pepsin.

Answer: (b)

Succus entericus lacks enzyme nucleases.

Answer: (c)

Brunner’s (duodenal) glands are confined to sub mucosa of duodenum and opens into crypts of Lieberkuhn. It secretes mucous only.

Answer: (d)