Students get through the MP Board Class 11th Biology Important Questions Chapter 16 Digestion and Absorption which are most likely to be asked in the exam.

## MP Board Class 11th Biology Important Questions Chapter 16 Digestion and Absorption

Digestion and Absorption Class 11 Important Questions Very Short Answer Type

Question 1.
What is dental formula ? Give dental formula of human. (NCERT)
Dental Formula: Formula representing number of different types of teeth found in the upper and lower half of the jaws is called as Dental formula.
Dental Formula = $$\frac{\text { Number of teeth in one half of upper jaw }}{\text { Number of teeth in one half of lower jaw }} \times 2$$
= $$\frac{\mathrm{I}, \mathrm{C}, \mathrm{P}, \mathrm{M}}{\mathrm{I}, \mathrm{C}, \mathrm{P}, \mathrm{M}}$$
Whereas,
I = Incisor,
C = Canine,
P = Premolar and M = Molar teeth
Dental formula of human = $$\frac{2,1,2,3}{2,1,2,3} \times 2=\frac{16}{16}=32$$

Question 2.
Name different types of teeth and give number of them in an adult person. (NCERT)
In human four types of teeth are found :

1. Incisor (Chisel shaped): helps to cut the food.
2. Canine (Dagger shaped): helps for tearing of food.
3. Premolar and Molar: helps for grinding food.
4. Dental formula of permanent teeth of adult human :
$$\frac{I_{2}, C_{1}, P_{2}, M_{3}}{I_{2}, C_{1}, P_{2}, M_{3}} \times 2$$
or
$$=\frac{2,1,2,3}{2,1,2,3} \times 2=\frac{8}{8} \times 2=\frac{16}{16}=32 \text { teeth }$$

Question 3.
Name bile pigments.
Bile contains two pigments :

1. Bilirubin: Yellow pigment.
2. Biliverdin : Geen pigment.

Question 4.
Write the name of disease caused by deficiency of protein and iodine.

• Disease caused due to deficiency of protein: Kwashiorkor and Marasmus.
• Disease caused due to deficiency of iodine: Goitre.

Question 5.
Write down the difference between chyme and chyle of man’s digestive system.

• Chyme is the food paste formed due to peristaltic movement of the walls of stomach, whereas chyle is the food paste formed due to peristaltic movement of duodenum.
• Chyme is acidic in nature whereas chyle is alkaline in nature.

Question 6.
Name two functions of small intestine.

1. Absorption of fatty substances.
2. Walls of intestine produce mucous which makes food sticky.

Question 7.
What is anaemic stage? How it is cured?
Anaemia is a stage in which the amount of haemoglobin in blood is decreased. The chief cause of this condition is the deficiency of iron. It is also caused due to deficiency of vitamin B6 and B12. It can be cured by taking iron elements, vitamin B6 and vitamin B12.

Question 8.
Is digestion of protein possible when trypsinogen is transferred into stomach?
The digestion of protein is not possible when enzyme trypsinogen is transferred into stomach because stomach contains HCl and thus, solution of stomach becomes acidic while trypsinogen enzyme can function only in alkaline medium.

Question 9.
Write the name of any four enzymes present in pancreatic juice.

1. Amylase,
2. Lipase,
3. Trypsin and
4. Chymotrypsin.

Question 10.
If carbohydrate digesting enzymes are added in stomach then digestion of carbohydrate is possible. Why?
Digestion of carbohydrate increases because amount of carbohydrate digesting enzyme increases.

Question 11.
Microvilli are found in intestine but are absent in stomach, why?
Microvilli present in intestine perform the absorption of food materials. These villi increase the absorbing surface of intestine. Absorption is not accompanied in stomach hence villi are not found within it.

Question 12.
How vitamin A affects the vision? Explain it.
Rods of retina are covered by a photosensitive pigment. These pigments decompose in sunlight but they are also synthesized in presence of vitamin A. Rhodopsin is not synthesized in the absence of vitamin A hence the vision of the person is affected and resulting night blindness.

Question 13.
What is lacteales? Where it is found?
Lacteales is a short lymph duct found in villi of intestine. It absorbs the fatty acid and glycerol in small intestine. Because of fat particle the colour of lymph is white.

Question 14.
How ingested fat is absorbed in the body?
First of all bile juice form the emulsion of fat then lipase enzyme hydrolyses emulsified fat into fatty acids and glycerol. Then it is absorbed by the microvillies of small intestine and passes into lacteal tubules and then through lymphatic system distributed to all parts of the body.

Question 15.
What is rickets? Name the vitamin, the deficiency of which is responsible for it.
Rickets disease occurs in the children. Bones become weak and bent. This disease is caused due to the deficiency of vitamin D.

Question 16.
How milk is digested in the stomach?
The gastric gland of the stomach secretes gastric juice which contains dil HCl and two inactive enzymes pepsinogen and prorenin. Inactive prorenin converts into active renin in the presence of dilute, hydrochloric acid. Renin hydrolyse milk protein (casein) into calcium paracaseinate.

Digestion and Absorption Class 11 Important Questions Short Answer Type

Question 1.
Define diphyodont, thecodont and heterodont.
1. Diphyodont: Two sets of teeth are produced :

1. Temporary or milk teeth,
2. Permanent teeth.
3. Temporary teeth are replaced by permanent teeth during the age period of 6-12 years.

2. Thecodont: Teeth are embedded into the socket of jawbones.
3. Heterodont: Teeth are of various sizes, shapes and structures. In man these are of 4 types: Incisors, canines, premolars and molars.

Question 2.
How does digestion of polysaccharide and disaccharide occurs in the alimentary canal?
(A) Digestion of Polysaccharide: Digestion of Polysaccharide like starch is completed in following three steps:
1. In the Buccal cavity: Salivary gland of the buccal cavity secretes saliva, which contains an enzyme ptyalin. Ptyalin hydrolyses starch into maltose.

2. In the Duodenum: Pancreas secretes pancreatic juice, which reaches to the duodenum, through pancreatic duct. Pancreatic juice contains Amylase enzyme, which hydrolyses starch into maltose.

3. In the Intestine: Intestinal gland of the intestine secretes intestinal juice (succus entericus) which contains maltase enzyme. Maltase hydrolyses maltose into two molecules of glucose.

(B) Digestion of Disaccharides: Disaccharides like Maltose, sucrose and lactose are digested in the intestine. Intestinal gland of intestine secretes Intestinal juice (succus entericus), which contains 3 enzymes for digesting disaccharides. They are Maltase, Sucrose and Lactose. They hydrolyse disaccharides in following ways :

Question 3.
Describe digestion of protein in the alimentary canal. (NCERT)
Digestion is physicochemical process which decompose complex chemical sub¬stances of food into simple substances so that they are absorbed by the wall of alimentary canal. Digestion of protein occurs by the help of gastric juice, pancreatic juice and intestinal juice in the different parts of the alimentary canal in the following way :

1. Buccal cavity: Digestion of protein does not occur in this part.
2. Stomach: In the stomach, gastric juice is found which contains HCl, pepsinogen and prorenin enzymes. These enzymes convert into their active form by the help of HCl.

Pepsin converts protein into proteases and peptone.

Rennin converts milk protein into calcium paracaseinate.

3. Duodenum: In the duodenum, pancreatic juice helps for the digestion of protein. Trypsin and chymotrypsin enzymes present in the pancreatic juice convert peptones into polypeptides.

4. Intestine: In the intestine, intestinal juice is found which contains erepsin enzyme which converts di, tri and polypeptides into amino acids.

Question 4.
Bile juice does not contain any digestive enzyme even then it is important for digestion, why? (NCERT)
Bile is a secretion of liver which emulsifies fat and activate some enzymes. Bile juice does not contain any digestive enzymes but still, it plays an important part like :

• It changes acidic food into alkaline one.
• It emulsifies fat so that lipase may act upon it.
• It converts inactive trypsin into active one.
• It instigates walls of intestine to start peristaltic movement.
• It’kills harmful bacteria of food.
• It neutralizes acidic nature of the food which comes from the stomach.

Digestion and Absorption Class 11 Important Questions Long Answer Type

Question 1.
How does digestion of butter occurs in your body? How its absorption occurs? Describe in details.
(A) Digestion of fat in our body: Digestion of fat in our body occurs in following steps:
1. Digestion in the stomach: Gastric gland of the stomach secretes gastric juice, which contains enzyme gastric lipase. It hydrolyses emulsified fat into fatty acid and glycerol. Gastric lipase is very slow in function.

2. Digestion in the Duodenum: Duodenum receivers bile juice from the liver and pancreatic juice from the pancreas.
Bile juice helps for emulsification of fat

Pancreatic juice contains lipase enzyme, which hydrolyses emulsified fat into fatty acid and glycerol.

3. Digestion in the Ileum : Ileum part of the intestine contains intestinal gland, which secretes intestinal juice (succus entericus). It hydrolyses emulsified fat into fatty acid and glycerol.

(B) Absorption of fat: After completion of digestion process in the intestine, still some fats remain undigested and remain in the form of mono and diglycerides. These undi¬gested fats combine with bile salt to form small globules called as micelles. These are absorbed by the cells of microvilli by diffusion, where they forms large globules by forming phospholipids.

Now, these large globules are called as chylomicron. Chylomicron reaches to the lymph capillaries present in the microvilli become milky in colour due to presence of large globules. Milky lymph is called as chyle and now these fine lymph capillaries are called as Lacteals, which opens into lymph vessels. These lymph vessels carries digested fat to the thoracic lymph duct from where it reaches to the hepatic portal system.

Question 2.
Give role of pancreatic juice in digestion of protein. (NCERT)
Pancreatic juice is secreted by the pancreas, which reaches to the duodenum through pancreatic duct. Pancreatic juice contains 6 enzymes but out to them three enzymes help for digestion of protein.

1. Inactive enzyme trypsinogen is converted into active trypsin by the intestinal enzyme enterokinase.

2. Inactive chymotrypsinogen is converted into active chymotrypsin by the activity of Trypsin.

3. Trypsin and Chymotrypsin both help to hydrolyse peptone into peptides.

4. Carboxypeptidase: It hydrolyses peptides into amino acids.

Question 3.
How does digestion of protein occurs in the stomach ?
Or
Explain the process of digestion in the stomach. (NCERT)
Digestion in stomach: Stomach is the widest part of the alimentary canal where food is kept for 1- 5 hours. Stomach contains a number of microscopic gastric glands. Secretion of gastric gland is called gastric juice. It contains proenzyme pepsinogen, HCl, mucus, a weak enzyme gastric lipase and intrinsic factor. In calf a weak enzyme rennin is also present.

Mucus protects the stomach wall against HCl and proteolytic enzyme pepsin. It also lubricates the food. HCl converts proenzyme pepsinogen into proteolytic enzyme pepsin. Pepsin is also autocatalytic. Other functions of HCl includes providing acidic pH for working of pepsin, stoppage of ptyalin action and prevention of bacterial growth. The enzymes of gastric juice helps in the digestion as follows :
1. Digestion by pepsin: It is secreted in the form of inactive pepsinogen and is activated by HCl to digest protein molecules.

2. Digestion by mucin: It is forming a protective sheath on mucous membrane after decreasing the acidic effect of gastric juice. Water and mucin of saliva moisten the food and make the mucous membrane slippery. Thus it helps in the process of digestion.

3. Digestion by rennin : It is secreted in the form of prorennin and is activated by HCl. It converts milk into curd and takes part in the process of digestion as follows :

4. Digestion by gastric lipase: It is responsible for hydrolysis of fats into fatty acids and glycerols.
At the end of its stay in stomach, the food is converted into a pulpy mass called chyme. The pyloric valve opens at intervals and chyme passes into duodenum part of small intestine.

Question 4.
Describe about the gland which contains the islets of Langerhans.
The islets of Langerhans are found in pancreas. It is a pink coloured small gland situated in the ‘U’ shaped portion of duodenum. It is covered by a membrane which is filled with a connective tissue. It contains a number of the lobules held together by connective tissue.

A lobule has several alveoli or acini. An alveolus possess a narrow cavity and a layer of glandular cells. The latter secrete pancreatic juice. The narrow cavity forms a ductule. The ductules form ducts, which join to produce a single pancreatic duct. The latter opens into duodenum either independently or along with common bile duct.

Question 5.
Give role of chymotrypsin. Name the gland from which it is secreted and also name two more enzymes belongs to same category by this gland. (NCERT)
Chymotrypsin is a proteolytic enzyme secreted as inactive form in the pancreatic juice called as chymotrypsinogen.
Chymotrypsinogen is activated by trypsin into active chymotrypsin.

Chymotrypsin is produced in inactive form as chymotrypsin in the pancreatic juice which is secreted by Pancreas. It reaches to the duodenum through pancreatic duct.
Two other enzyme belongs to some category, i.e. proteolytic enzymes secreted by pancreas are :

1. Trypsinogen and
2. Carboxypeptidase.

Question 6.
What will happen if hydrochloric acid is not secreted in the stomach? (NCERT)
Functions of HCl in the stomach are as follow :

1. Stops activity of ptyalin as due to HCl, medium of food become acidic.
2. Enzymes of gastric juice become active in acidic medium.
3. It destroys harmful germs present in the food.
4. It activates inactive enzymes pepsinogen and prorenin into active pepsin and renin respectively.
5. Helps to digest bones.
6. Regulates opening and closing of pyloric aperture.
If hydrochloric acid is not secreted in the stomach then all above functions will be effected.

Question 7.
(a) Villi are found in the intestine but not in the stomach, why?
(b) How does pepsinogen converts into active form?
(c) What are the basic layers of wall of the alimentary canal?
(d) How does bile help to digest fat?
(a)Microvilli present in intestine perform the absorption of food materials. These villi increase the absorbing surface of intestine. Absorption is not accompanied in stomach hence villi are not found within it.

(b) Gastric juice secreted by gastric gland of the stomach contains dil HCl, Which converts inactive pepsinogen into active pepsin.

(c) Basic layers of the wall of the alimentary canal are – Serosa, Muscular layer, Submucosa and Mucosa.
(d) Bile juice secreted by the liver reaches to the duodenum through bile duct. It do not contain any enzyme but help for digestion in following ways :

• It helps for emulsification of fat.
• It helps to neutrilize acidic nature of the food which comes from the stomach, because bile juice itself is alkaline in nature.

Question 8.
Give functions of Liver. (NCERT)
Functions of Liver: Liver is the most important organ of the body, it performs the following function:

1. Excess quantity of glucose in blood in liver cells is converted into glycogen.
2. Excess quantity of amino acids in hepatic cells are converted into urea.
3. Synthesis of albumin from amino acids.
4. Production of blood proteins like prothrombin and fibrinogen which are essential for blood coagulation.
5. Production of Heparin, an enzyme which prevents clotting of blood in the blood vessels.
6. Production of R.B.C. during foetal life.
7. Storage of Vitamin A, B12 and D.
8. Storage of inorganic substances like copper and iron.
9. It charges acidic food into alkaline one.
10. Excess quantity of glucose present in the blood reaches to liver and converted into fat by lipogenesis process and stored in the adipose tissue.
11. When there is lack of glucose in the blood Glycogen of the liver decomposes by glycogenolysis process to proudce glucose and supplied to the blood.
12. Kupffer cells found in the cells of liver kills harmful bacterias by phagocytic action.
13. It helps for digestion of fat by emulsification by its bile juice. It also help to neutralize acidic nature of the food as bile juice is alkaline.
14. It helps to store copper and iron.

Digestion and Absorption Class 11 Important Questions Objective Type

Question 1.
The function of bile is:
(a) Emulsification of fat
(b) Excretion of waste materials
(c) Digestion of fat by enzymes
(d) None of these.
(a) Emulsification of fat

Question 2.
Amylase enzyme act on:
(a) Carbohydrate
(b) Protein
(c) Fat
(d) Sugar.
(a) Carbohydrate

Question 3.
Lactase is found in:
(a) Saliva
(b) Bile
(c) Pancreatic juice
(d) Intestinal juice.
(d) Intestinal juice.

Question 4.
Goitre affects:
(a) Metabolism
(b) Vision
(c) Excretion
(d) Speech.
(a) Metabolism

Question 5.
Which of the following pair is correctly matched:
(a) Renin-protein
(b) Amylase-lactose
(c) Trypsin-starch
(d) Invertase-sucrose.
(a) Renin-protein

Question 6.
Enzyme arginase is found in:
(a) Buccal cavity
(b) Stomach
(c) Intestine
(d) Liver.
(d) Liver.

Question 7.
Bile salts are secreted into alimentary canal, where they involve in the absorption of:
(a) Na and Ca ions
(b) Fat-soluble vitamins
(c) Amino-acids and monosaccharides
(d) All the nutrients present in chyme.
(b) Fat-soluble vitamins

Question 8.
Found in the gastric juice: (NCERT)
(a) Pepsin, Lipase, Renin
(b) Trypsin, Lipase, Renin
(c) Trypsin, Pepsin, Lipase
(d) Trypsin, Pepsin, Renin.
(a) Pepsin, Lipase, Renin

Question 9.
Succus entericus name is given for: (NCERT)
(a) Joining part of the Ileurn and Large intestine
(b) Intestinal juice
(c) Swelling in the alimentary canal
(d) Appendix.
(b) Intestinal juice

Question 10.
Rickets can be prevented by taking:
(a) Oranges
(b) Carrots
(c) Green vegetables
(d) Calciferol.
(d) Calciferol.

Question 11.
Amylolytic enzymes are formed in:
(a) Salivary glands and liver
(b) Stomach and liver
(c) Stomach and pancreas
(d) Salivary glands and pancreas.
(d) Salivary glands and pancreas.

Question 12.
islets of Langerhans produce:
(a) Insulin
(b) Rennin
(c) Ptyalin
(d) HCl.
(a) Insulin

Question 13.
The hardest substance of vertebrátes body is:
(a) Keratin
(b) Enamel
(c) Dentine
(d) Chondrin.
(a) Keratin

Question 14.
Pepsin is secreted in:
(a) Intestine
(b) Liver
(d) Stomach.
(d) Stomach.

Question 15.
Peyer’s patches contain:
(a) Mucus
(b) Sebum
(c) Lymphocytes
(d) Red blood cells.
(d) Red blood cells.

Question 16.
The pH of succus entericus is:
(a) 78
(b) 66
(c) 56
(d) 20.
(c) 56

Question 17.
Digestion of protein takes place in :
(a) Duodenum and stomach
(b) Stomach and oesophagus
(c) Small and large intestine
(d) Intestine and rectum.
(a) Duodenum and stomach

Question 18.
The food present in stomach consisting of acidic medium is called :
(a) Chegle
(b) Chyme
(c) Bolus
(d) All of these.
(b) Chyme

Question 19.
Goblet cells secretes:
(a) Enzymes
(b) Mucus
(c) Hormones
(d) HCl.
(b) Mucus

Question 20.
Glycogen is stored in the:
(a) Blood
(b) Liver
(c) Lungs
(d) Kidney.
(b) Liver

Question 21.
Herbivorous organisms can digest cellulose because :
(a) In the gastric juice enzymes for this are found
(b) Bacterias present in the caecum help for this
(c) Alimentary canal is long
(d) Molar and premolar teeth help for chewing.
(b) Bacterias present in the caecum help for this

Question 22.
Pancreatic juice helps for digestion of:
(a) Protein
(b) Protein and fat
(c) Carbohydrates and Protein
(d) Protein, fat, carbohydrates.
(d) Protein, fat, carbohydrates.

Question 23.
Disease caused due to deficiency of vitamin B12 :
(a) Beri-beri
(b) Pellagra
(c) Colossi
(d) Scurvy.
(a) Beri-beri

Question 24.
What is called as thiamine :
(a) Vitamin-B
(b) Vitamin-A
(c) Vitamin-B,
(d) Vitamin B complex.
(c) Vitamin-B,

Question 25.
Enterokinase induces:
(a) Pepsinogen
(b) Trypsin
(c) Pepsin
(d) Trypsinogen.
(d) Trypsinogen.

Question 26.
All digestive enzymes are:
(a) Lipases
(b) Hydrolase
(c) Transferase
(d) Oxidases.
(b) Hydrolase

Question 27.
In the caecum of rabbit digestion of which substance occurs
(a) Fat
(b) Starch
(c) Cellulose
(d) Protein.
(c) Cellulose

Question 28.
Disease caused due to deficiency of vitamin-D is:
(a) Rickets
(b) Scurvy
(c) Night blindness
(d) Pellagra.
(a) Rickets

Question 29.
Pellagra is caused due to deficiency of
(a) Vitamin-B5
(b) Vitamin-C
(c) Vitamin-D
(d) Vitamin-E.
(a) Vitamin-B5

Question 30.
Ptyalin hydrolyses:
(a) Fat
(b) Protein
(c) Lipid
(d) Starch.
(d) Starch.

Question 31.
islet of Langerhans produces:
(a) Insulin
(b) Trypsin
(c) Lipase
(d) Amylase.
(a) Insulin

Question 32.
Pepsin is produced in the:
(a) Intestine
(b) Liver
(d) Stomach.
(d) Stomach.

2. Fill in the blanks:
1. The secretion of liver is …………………………. .
Bile,

2. Marasmus disease is caused due to deficiency of …………………………. in food.
Protein,

3. Villi are found in …………………………. and …………………………. .
Jejunum, ileum,

4. The secretion of HCl and gastric juice is controlled by …………………………. hormone.
Enterogestron,

5. Herbivorous animal can digest cellulose because their …………………………. is well-developed.
Caecum,

6. Rickets caused due to deficiency of …………………………. .
Vitamin D.

7. Pepsin formation takes place in …………………………. .
Stomach,

8. In digestion emulsification of fat takes place by …………………………. .
Bile juice,

9. Food reaches to stomach from oesophagus by …………………………. movement.
Peristalsis,

10. Digestive system of human consists of …………………………. and …………………………. .
Alimentary canal, Digestive glands,

11. Saliva is produced by …………………………. pairs of salivary glands.
Three,

12. Wall of the alimentary canal from oesophagus to rectum consists of …………………………. layers.
Three or four.

3. Match the following:

(A)

 Column ‘A’ Column ‘B’ 1. Enterokinase (a) Casein 2. Ruminant (b) Vitamin C 3. Rennin (c) HCl 4. Collagen (d) Reticulum 5. Pepsin (e) Trypsin.

1. (e) Trypsin.
2. (d) Reticulum
3. (a) Casein
4. (b) Vitamin C
5. (c) HCl.

(B)

 Column ‘A’ Column ‘B’ 1. Night blindness (a) Vitamin C 2. Pelagra (b) Vitamin B 3. Beriberi (c) Vitamin B12 4. Scurvy (d) Vitamin A 5. Pemitious anaemia (e) Nicotinamide.

1. (d) Vitamin A
2. (e) Nicotinamide.
3. (b) Vitamin B
4. (a) Vitamin C
5. (c) Vitamin B12.

(C)

 Column ‘A’ Column ‘B’ 1. Bilirubin and Biliverdin (a) Parotid 2. Hydrolysis of starch (b) Bile juice 3. Digestion of fat (c) Lipase 4. Salivary gland (d) Amylase.

1. (b) Bile juice
2. (d) Amylase.
3. (c) Lipase
4. (a) Parotid.

1. Write the name of bile pigments.
Bilirubin and Biliverdin,

2. Name the vitamin known as anti sterility vitamin.
Vitamin E,

3. Write the name of disease caused due to deficiency of vitamin B.
Beriberi,

4. Write the name of any four water-soluble vitamins.
Vitamin B1, B2, B6 and Vitamin C,

5. Write the name of any four enzymes found in pancreatic juice.
Trypsin, Amylase, Lipase, Nuclease,

6. Write the name of any two diseases of children caused due to the deficiency of protein.
Kwashiorkor, Marasmus,

7. Write the name of organ functioning as endocrine as well as exocrine gland.
Pancreas,

8. Write the name of any two protein-digesting enzymes.
Trypsin, Chymotrypsin,

9. Name the vitamin responsible for night blindness.
Vitamin A,

10.Which provides more energy, carbohydrate or fat?
Fat,

11. Name the disease caused due to deficiency of Vitamin-C.
Scurvy,

12.Name the disease caused due to deficiency of Vitamin-D.
Rickets,

13.Name the disease caused due to deficiency of iodine.
Goitre,

14.Name the hormone induce secretion of gastric juice.
Gastrin,

15. Which component of food is digested by bile juice?
Lipid and fat,

16. Which enzyme is secreted by salivary gland?
Ptyalin,

17. Where gastric juice is secreted?