NEET Biology Digestion and Absorption MCQs Set 20

Answer: (d) secretin

Explanation:
1. Secretin, from the duodenal mucosa, stimulates the pancreas to release a watery, bicarbonate-rich juice.
2. Cholecystokinin stimulates enzyme release, but secretin is the main stimulant of juice release among the options.
3. Enterokinase activates trypsinogen and does not stimulate release.

Teacher's Note:
1. Secretin acts on the pancreas.
2. CCK acts on the gall bladder and pancreas.

Answer: (d) fundic part of stomach

Explanation:
1. Chief (zymogenic) cells secrete pepsinogen and are found mainly in the fundic part of the stomach, in the gastric glands.

Teacher's Note:
1. Chief cells make pepsinogen.
2. Parietal (oxyntic) cells make HCl.

Answer: (c) bile salts

Explanation:
1. Bile salts lower the surface tension of fat and break large fat globules into small droplets (emulsification).
2. Lipase digests fat but does not emulsify it.

Teacher's Note:
1. Bile has no enzymes.
2. Emulsification increases the surface area for lipase.

Answer: (d) different cells

Explanation:
1. Pancreatic juice is made by acinar cells.
2. The hormones insulin and glucagon are made by the islets of Langerhans, which are different cells.

Teacher's Note:
1. Pancreas is both exocrine and endocrine.
2. Acini are exocrine and islets are endocrine.

Answer: (a) sub-mucosa of duodenum

Explanation:
1. Brunner's glands lie in the submucosa of the duodenum.
2. They secrete mucus and an alkaline fluid that protects the duodenum from the acid chyme.

Teacher's Note:
1. Brunner's glands are in the duodenum.
2. Crypts of Lieberkuhn are in the whole small intestine.

Answer: (d) small intestine

Explanation:
1. Most of the fat digestion takes place in the small intestine by pancreatic and intestinal lipase after emulsification by bile.

Teacher's Note:
1. Lipase of the pancreas is the major fat-digesting enzyme.
2. Little fat is digested in the stomach.

Answer: (d) liver

Explanation:
1. Kupffer cells are the phagocytic cells lining the liver sinusoids.
2. They remove old cells and germs.

Teacher's Note:
1. Kupffer cells are macrophages of the liver.
2. Do not confuse with microglia of the brain.

Answer: (d) enterogasterone

Explanation:
1. Enterogasterone from the intestine inhibits gastric secretion and motility.
2. Gastrin stimulates gastric juice.

Teacher's Note:
1. Enterogasterone is the brake on the stomach.
2. It is released when fat is present in the duodenum.

Answer: (a) Maltose — Maltase

Explanation:
1. Maltase breaks maltose into two glucose molecules.
2. Rennin acts on milk casein, steapsin digests fat, and chymotrypsin acts on proteins.

Teacher's Note:
1. Each enzyme has its own substrate.
2. Match the enzyme with the food.

Answer: (a) These all are proteins

Explanation:
1. Amylase, renin and trypsin are all enzymes, and all enzymes are proteins.
2. Amylase digests starch and the other two digest proteins, so option b is false.

Teacher's Note:
1. Enzymes are proteins.
2. Their optimum pH differs.

Answer: (d) All of these ter Specific

Explanation:
1. Pancreatic juice has enzymes for carbohydrates (amylase), proteins (trypsin) and fats (lipase).
2. Without the pancreas all three remain undigested.

Teacher's Note:
1. Pancreatic juice is the most complete digestive juice.
2. It is alkaline.

Answer: (b) Ameloblast

Explanation:
1. Enamel is secreted by the ameloblasts, which are lost after the tooth erupts.
2. Odontoblasts make dentine and osteoblasts make bone.

Teacher's Note:
1. Enamel is the hardest substance in the body.
2. It cannot be replaced once damaged.

Answer: (c) glucose + galactose

Explanation:
1. Lactose (milk sugar) is a disaccharide of glucose and galactose joined by a glycosidic bond.
2. Sucrose is glucose plus fructose.

Teacher's Note:
1. Lactase digests lactose.
2. Lactose intolerance is lack of lactase.

Answer: (a) ileum

Explanation:
1. Lacteals are lymph vessels in the villi of the small intestine, mainly the ileum.
2. They absorb fat as chylomicrons.

Teacher's Note:
1. Lacteals carry absorbed fats.
2. They join the lymphatic system.

Answer: (d) intestine Truem

Explanation:
1. Cholecystokinin and duocrinin are hormones secreted by the intestinal mucosa.
2. They control the secretion of bile and pancreatic juice.

Teacher's Note:
1. Gastro-intestinal hormones come from the gut wall.
2. They act in digestion.

Answer: (d) DNA which gets digested by pancreatic DNAase

Explanation:
1. Boiled potato has starch, which is digested by amylases.
2. Lactose is not in potato, cellulose is not digested by humans, and DNA of the cells is digested by pancreatic DNase.

Teacher's Note:
1. Humans have no cellulase.
2. Nucleases digest nucleic acids.

Answer: (c) First carbohydrates, next fats and lastly proteins

Explanation:
1. During fasting the body first uses stored carbohydrates (glycogen), then fats, and last proteins.

Teacher's Note:
1. Glucose is the first fuel.
2. Protein is spared as it is needed for structure.

Answer: (c) In the absence of HC1 secretion, inactive pepsinogen is not converted into the active enzyme pepsin

Explanation:
1. Parietal cells secrete HCl.
2. If they are blocked, pepsinogen is not converted into active pepsin because it needs acid.

Teacher's Note:
1. HCl also kills germs.
2. Pepsin is the protein-digesting enzyme of the stomach.

Answer: (d) smooth movement of food down the intestine ter Specific

Explanation:
1. Goblet cells secrete mucus which lubricates the intestinal lining.
2. If they fail, the smooth movement of food through the intestine suffers.

Teacher's Note:
1. Mucus protects the gut.
2. Goblet cells are in the mucosa.

Answer: (d) I 2/2, C 1/1, PM 2/2, M 3/3

Explanation:
1. The adult human dental formula is 2123/2123 (I 2/2, C 1/1, PM 2/2, M 3/3).
2. This gives 32 teeth.

Teacher's Note:
1. Learn the dental formula as I C PM M.
2. Children have 20 milk teeth.

Answer: (d) Brunner’s glands are present in the submucosa of stomach and secrete pepsinogen

Explanation:
1. Brunner's glands are in the submucosa of the duodenum, not the stomach, and they secrete mucus.
2. Pepsinogen is secreted by chief cells of the stomach.

Teacher's Note:
1. Check the gland with its location.
2. Goblet cells and oxyntic cells statements are correct.

Answer: (b) Protein — Kwashiorkor

Explanation:
1. Kwashiorkor results from protein deficiency in children, with swollen lips, skin changes and irritability.
2. Beri-beri is thiamine deficiency, pellagra is niacin deficiency and goitre is iodine deficiency.

Teacher's Note:
1. Kwashiorkor shows oedema.
2. Marasmus is protein-calorie deficiency.

Answer: (a) D

Explanation:
1. Vitamin D helps the absorption of calcium and phosphorus from the intestine.
2. Its deficiency causes rickets and low calcium.

Teacher's Note:
1. Vitamin D is the sunshine vitamin.
2. It makes calcium usable.

Answer: (a) fats

Explanation:
1. Fats give about 9 kcal per gram, more than carbohydrates or proteins (4 kcal).
2. Vitamins are not energy sources.

Teacher's Note:
1. Fat has the highest energy value.
2. It is stored for long term use.

Answer: (c) scurvy

Explanation:
1. Vitamin C (ascorbic acid) prevents scurvy.
2. Rickets is vitamin D deficiency and pellagra is niacin deficiency.

Teacher's Note:
1. Citrus fruits and amla are good sources.
2. Scurvy causes bleeding gums.

Answer: (c) Fluorine

Explanation:
1. Excess fluoride in drinking water causes dental fluorosis (mottled teeth).
2. Mercury, chlorine and boron do not cause this.

Teacher's Note:
1. Safe fluoride limit is about 1 ppm.
2. It causes brown mottled enamel.

Answer: (d) vitamin-K

Explanation:
1. Vitamin K is needed to make clotting factors such as prothrombin.
2. Its deficiency causes bleeding (haemorrhagic disease) in new-born babies.

Teacher's Note:
1. Vitamin K is the clotting vitamin.
2. Gut bacteria also make it.