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NCERT Exemplar Class 11 Biology Solutions Chapter 16 Digestion and Absorption

NCERT Exemplar Class 11 Biology Solutions Chapter 16 Digestion and Absorption

Edited By Priyanka kumari | Updated on Aug 19, 2022 10:59 AM IST

NCERT Exemplar Class 11 Biology chapter 16 solutions explores the process of digestion and absorption in human beings. Food is vital for the survival of both humans and animals as it is from this food that we obtain major components like carbohydrates, proteins, fats, vitamins and minerals which thereby gives us the energy to carry out our day-to-day activities. Digestion is the process in which complex food items are converted into simpler substances for easier and proper digestion and absorption to take place. NCERT Exemplar Class 11 Biology solutions chapter 16 explains the different types of digestive disorders and what causes them in the first place and what happens when it happens.

Also, check NCERT Solutions for Class 11 other subjects

NCERT Exemplar Class 11th Biology Solution Chapter 16 Digestion And Absorption:

Multiple Choice Questions:

Question:1

Select what is not true of intestinal villi among the following

(a) They possess microvilli
(b) They increase the surface area
(c) They are supplied with capillaries and the lacteal vessels
(d) They only participate in digestion of fats

Answer:

The answer is the option (d) They only participate in digestion of fats.

Question:2

Hepato-pancreatic duct opens into the duodenum and carries
(a) Bile (b) Pancreatic juice (c) Both bile and pancreatic juice (d) Saliva

Answer:

The answer is the option (c) Hepato-pancreatic duct opens into the duodenum and carries both bile and pancreatic juice.

Question:3

One of the following is not a common disorder associated with the digestive system

(a) Tetanus (b) Diarrhoea (c) Jaundice (d) Dysentery

Answer:

The answer is the option (a) Tetanus is not a common disorder associated with the digestive system.

Question:4

A gland not associated with the alimentary canal is
(a) Pancreas (b) Adrenal (c) Liver (d) Salivary glands

Answer:

The answer is the option (b) A gland not associated with the alimentary canal is adrenal (this is endocrine gland).

Question:5

Match the two columns and select the correct among options given


Column I
Column II
A.Biomacromolecules(i)Alimentary canal and of food associated gland
B.Human digestive system(ii)Embedded in jawbones
C.Stomach(iii)Outer wall of visceral organs
D.Thecodont(iv)Converted into simple substances
E.Serosa(v)J-shaped bag like structure

Options:
(a) A—(ii), B—(i), C—(v), D—(iii), E—(iv)
(b) A—(iv), B—(i), C—(v), D—(ii), E—(iii)
(c) A—(i), B—(ii), C—(iii), D—(iv), E—(v)
(d) A—(i), B—(iii), C—(ii), D—(iv), E-(v)

Answer:

The answer is the option (b) A—(iv), B—(i), C—(v), D—(ii), E—(iii)

Column I Column II A. Biomacromolecules (i) Alimentary canal and of food associated gland B. Human digestive system (ii) Embedded in jawbones C. Stomach (iii) Outer wall of visceral organs D. Thecodont (iv) Converted into simple substances E. Serosa (v) J-shaped bag like structure Options: (a) A—(ii), B—(i), C—(v), D—(iii), E—(iv) (b) A—(iv), B—(i), C—(v), D—(ii), E—(iii) (c) A—(i), B—(ii), C—(iii), D—(iv), E—(v) (d) A—(i), B—(iii), C—(ii), D—(iv), E-(v)
Edit Q

Question:6

Match the two columns and select the right one among options given

Column IColumn II
A.Duodenum(i)A cartilagenous flap
B.Epiglottis(ii)Small blind sac
C.Glottis(Hi)‘C’ shaped structure emerging from the stomach
D.Caecum(iv)Opening of windpipe
(a) A—(i), B—(ii), C—(iii), D—(iv)
(b) A—(iv), B—(iii), C—(ii), D—(i)
(c) A—(iii), B—(i), C—(iv), D—(ii)
(d) A—(ii), B—(iv), C—(i), D—(iii)

Answer:

The answer is the option (c) A—(iii), B—(i), C—(iv), D—(ii)

Question:7

Match the enzymes with their respective substrates choose the right one among options given.

Column IColumn II
A.Lipase(i)Dipeptides
B.Nuclease(ii)Fats
C.Carboxypeptidase(iii)Nucleic acids
D.Dipeptidases(iv)Proteins, peptones and proteoses
Options:
(a) A—(ii), B—(iii), C—(i), D—(iv)
(b) A—(iii), B—(iv), C—(ii), D—(i)
(c) A—(iii), B—(i), C—(iv), D—(ii)
(d) A—(ii), B—(iii), C—(iv), D—(i)

Answer:

The answer is the option (d) A—(ii), B—(iii), C—(iv), D—(i)

Question:8

Dental Formula for human beings is
a. 3223/3223

b. 2123/2123

c.1232/1232

d. 2233/2233

Answer:

b. 2123/2123

Question:9

Liver is the largest gland and is associated with functions, choose one which is not correct
(a) Metabolism of carbohydrate
(b) Digestion of fat
(c) Formation of bile
(d) Secretion of hormone called gastrin

Answer:

The answer is the option (d) secretion of hormone called gastrin; as the liver performs all the other functions specified herein.

Question:10

Mark the right statement among the following
(a) Trypsinogen is an inactive enzyme
(b) ’trypsinogen is secreted by intestinal mucosa
(c) Enterokinase is secreted by pancreas
(d) Bile contains trypsin

Answer:

The answer is the option (a) Trypsinogen is an inactive enzyme.

Question:2

Trypsinogen is an inactive enzyme of pancreatic juice. It is activated by an enzyme, enterokinase. Which tissue/ cells secrete this enzyme? How is it activated?

Answer:

Internal mucosa secretes trypsinogen. The enzyme enterokinase activates inactive trypsinogen into active trypsin.

Question:3

In which part of the alimentary canal does absorption of water, simple sugars, and alcohol takes place?

Answer:

Absorption of water, simple sugar and alcohol occurs in the stomach.

Question:4

Name the enzymes involved in the breakdown of nucleotides into sugars and bases?

Answer:

The enzymes involved in the breakdown of nucleotides into sugar and base is nuclease.

Question:5

Define digestion in one sentence.

Answer:

Digestion can be defined as the conversion of complex food substances into simpler absorbable forms.

Question:8

Does gall bladder make bile?

Answer:

No. the Bile juice is produced by the liver.





Question:9

Correct the following statements by deleting one of the entries (given in bold).

(a) Goblet cells are located in the intestinal mucosal epithelium and secrete
chymotrypsin/mucus.

(b) Fats are broken down into di- and monoglycerides with the help of
amylase/lipases.

(c) Gastric glands of stomach mucosa have oxyntic cell/ chief cells which
secrete HCI.

(d) Saliva contains enzymes that digest
starch/protein.

Answer:

(a) Mucus
(b) Lipase
(c) Oxyntic cells.
(d) Starch.

Short Answer Type Questions:

Question:1

What is pancreas? Mention the major secretions of the pancreas that are helpful for digestion.

Answer:

The pancreas is a compound gland, i.e. both endocrine and exocrine glands. It is situated between the limbs of the U-shaped duodenum. It is a mixed gland since it contains both exocrine and endocrine parts. The exocrine portion of this gland secretes the pancreatic juice released in the duodenum and containing digestive enzymes. The digestive enzyme is alkaline and neutralizes the acid present in the food coming from the stomach into the duodenum. Whereas the endocrine portion of this gland secretes hormones: insulin and glucagon that helps maintain the level of sugar in the blood.

Question:2

Name the part of the alimentary canal where major absorption of digested food takes place. What are the absorbed forms of different kinds of food materials?

Answer:

The part of the alimentary canal where major absorption of digested food takes place in the small intestine. Carbohydrate is absorbed in glucose form, Proteins are absorbed in the form of amino acids, whereas fats are absorbed in the form of fatty acids and glycerol.

Question:3

List the organs of the human alimentary canal and name the major digestive glands with their location.

Answer:

The organ present in the human alimentary canal includes: Mouth, Oesophagus, Stomach, Small Intestine, Large Intestine and Rectum
The major digestive glands are:
(a) Salivary gland: Mouth, (b) Gastric glands: Stomach, (c) Liver: adjacent to the stomach, (d) Pancreas: Below stomach.

Question:4

What is the role of the gall bladder? What may happen if it stops functioning or is removed?

Answer:

The role of the gall bladder is to store bile juice secreted by the liver and release it as and when required in the duodenum.
In case if the gall bladder stops functioning or, bile directly moves to the small intestine. The concentration of bile decreases, but the body learns to adjust to this change.

Question:5

Correct the statement given below by the right option shown in the bracket against them

(a) Absorption of amino acids and glycerol takes place in the___.
(small intestine/ large intestine)

(b) The feces in the rectum initiate a __reflex causing an urge for its removal.
(neural /hormonal)

(c) Skin and eyes turn yellow in__ infection.
(liver /stomach)

(d) Rennin is a proteolytic enzyme found in gastric juice in__
(infants/adults).

(e) Pancreatic juice and bile are released through.
(intestine-pancreatic/ hepatopancreatic duct)

(f) Dipeptides, disaccharides, and glycerides are broken down into simple substances in the region of ___small intestine.
(jejunum/ duodenum).

Answer:

(a) Small intestine
(b) Neural
(c) Liver
(d) Infants
(e) Hepato-pancreatic duct
(f) Duodenum

Question:6

What are the three major types of cells found in the gastric glands? Name their secretions.

Answer:

The major types of cells in gastric glands along with their secretion are:
(A) Mucous neck cells secrete mucus
(B) Peptic or chief cells secrete Pepsinogen, Prorennin
(C) Parietal or oxyntic cells secrete HCI and Intrinsic Factor.

Question:7

How is the intestinal mucosa protected from the acidic food entering from the stomach?

Answer:

The activities of the gastrointestinal tract, are regulated by the neural system as well as the hormonal system. Many intrinsic and extrinsic nerves connect this tract. These nerves help in the coordinated functioning of several parts of the alimentary canal. Moreover, there are some hormones as well that play an important role in the coordination of these functions.

Question:8

How are the activities of gastro-intestinal tract regulated?

Answer:

Activities of the gastrointestinal tract are under neural and hormonal control for proper coordination of different parts:
(i) The sight, smell and/or the presence of food in the oral cavity can stimulate the secretion of saliva.
(ii) Similarly, gastric and intestinal secretions are also stimulated by neural signals.
(iii) The muscular activities of different parts of the alimentary canal can also be moderated by neural mechanisms (both local and through CNS).
(iv) Hormonal control of the secretion of digestive juices is carried out by local hormones produced by the gastric and intestinal mucosa.

Question:9

Distinguish between constipation and indigestion. Mention their major causes.

Answer:

ConstipationIndigestion
This can happen because of the intake of less water and roughage in the diet.This can happen because of inadequate enzyme secretion, food poisoning, or anxiety.
Bowel movement is irregular, and feces are retained in the rectum.Improper indigestion of food gives a feeling of fullness.
This can be usually cured by improving the intake of water and roughage and by exercise.This may need medicines for cure.


Question:10

Describe the enzymatic action on fats in the duodenum.

Answer:

The bile secreted by the liver first carries out the emulsification of fat. After that, the fat is broken down by enzyme lipase into di- and monoglycerides.

Long Answer Type Questions:

Question:1

A person had roti and dal for his lunch. Trace the changes in those during its passage through the alimentary canal.

Answer:

Let us first determine what nutrients had the man is taken. Roti mainly consists of carbohydrates and fibres, whereas dal contains protein. It may also contain fat due to the addition of oil during cooking.
Thus, the trajectory of the diet would be as follows:

a) Oral Cavity: Saliva is mixed with food, making it a semi-solid paste, which is easier to digest. Moreover, the enzyme, salivary amylase in saliva digests starch. The starch of food is converted into maltose during this process.
b) Oesophagus: No digestion occurs inside the oesophagus.
c) Stomach: Food, once it reaches the stomach, is further churned into an even finer paste. Hydrochloric acid is mixed with the food, which kills germs in the food, if any, as well as it provides acidic pH for optimum activity of pepsin. Partial digestion of protein begins in the stomach. Here, the protein present in dal is converted by pepsin into peptones and proteases.
d) Small intestine: Pancreatic juices flow till here. They contain pancreatic amylase which converts polysaccharides into disaccharides. This step further processes the carbohydrates from the roti. Chymotrypsin further breaks peptones and proteoses into dipeptides. Intestinal juice contains various enzymes, which helps in digestion of all the nutrients. The dipeptides are broken down into Amino acids by enzyme Dipeptidases. Maltose breaks into glucose with the help of Maltase. Lactose breaks into glucose and galactose with the help of lactase. Sucrose breaks into glucose and fructose with the help of Sucrase. The di- and monoglycerides are broken down into fatty acids and glycerol with the help of Lipases.

Once all the nutrients are finally converted into their simpler forms, they get absorbed by the walls of the small intestine. After that, the remaining undigested food is sent to the large intestine and is passed on to the rectum.

Question:2

What are the various enzymatic types of glandular secretions in our gut helping digestion of food? What is the nature of end products obtained after complete digestion of food?

Answer:

a) Secretions from Gastric Glands: These glands secrete gastric juice which contains hydrochloric acid and the enzyme pepsin. In infants, rennin is also secreted by the stomach. Rennin helps in the digestion of milk.

b) Secretions from the Liver: The liver produces the bile juice. Bile does not contain any enzyme but plays an important role in digestion. It facilitates the emulsification of fats so that its digestion can be easier. Bile also provides an alkaline medium so that the enzymes in the small intestine can work.

c) Secretions from Pancreas: Pancreas secretes pancreatic juice which contains inactive enzymes like amylase, lipase, nuclease; trypsinogen and chymotrypsinogen.Trypsinogen is activated by an enzyme enterokinase into active trypsin,secreted by the intestinal mucosa. Trypsin, then activate other enzymes in the pancreatic juice. Amylase digests carbohydrate, and trypsin/chymotrypsin digests protein.

d) Secretions from Small Intestine: Small intestine secretes succus entericus which contains various enzymes including dipeptidase, lipase, lactase, etc.

e) End Products of Digestion: The final products of digestion are simpler substances like glucose, amino acids, fatty acids, and glycerol. These substances can be easily absorbed by the villi present in the small intestine.

Question:3

Discuss the mechanisms of absorption.

Answer:

The Absorption of digested food happens through three mechanisms,namely: passive, active or facilitated transport mechanisms.
Simple Diffusion: Small amounts of monosaccharides, amino acids, and some electrolytes are absorbed by diffusion. The passage of the above substances into the blood depends on the concentration gradient.
Facilitated Transport: Fructose, as well as some amino acids, are absorbed with the help of carrier ions like Na+. This method is known as facilitated transport.
Transport of Fatty Acids and glycerols: These substances are not absorbed into the blood because these are insoluble. They are made into small droplets; called micelles. These move to the intestinal mucosa. In the intestinal mucosa, these micelles get converted into very small protein-coated globules, called chylomicrons. The chylomicrons are then transported into the lymph vessels in the villi. The lymph vessels finally release them into the bloodstream.

Question:4

Discuss the role of hepatopancreatic complex in the digestion of carbohydrate, protein, and fat components of food.

Answer:

The hepato-pancreatic complex is very crucial for the digestion of carbohydrates, protein, and fat.

Role of Liver: Liver produces the bile juice. Bile does not contain any enzyme but plays an important role in digestion. It facilitates the emulsification of fats
so that its digestion can be easier. Bile also provides an alkaline medium so that the enzymes in the small intestine can work.

Role of Pancreas: Pancreas secretes pancreatic juice which contains inactive enzymes like amylase, lipase, nuclease; trypsinogen and chymotrypsinogen.

Trypsinogen is activated by an enzyme enterokinase into active trypsin, secreted by the intestinal mucosa. Trypsin, then activate other enzymes in the pancreatic juice. Amylase digests carbohydrate, and trypsin/chymotrypsin digests protein.

Question:5

Explain the process of digestion in the buccal cavity with a note on the arrangement of teeth.

Answer:

Arrangement of Teeth: In human beings, each tooth is embedded in a socket of the jawbone. This type of attachment is known as the diphyodont. Human beings get two sets of teeth in their lifetime, i.e. temporary teeth, and permanent teeth. Milk teeth are temporary and are replaced by permanent teeth. This type of arrangement is diphyodont.
There are four types of teeth in human beings, namely incisors, canines, premolars, and molars. Each half of a jaw contains numbers of each type of teeth. This can be shown by the following dental formula: 2123/2123. This shows that there are 2 incisors, 1 canine, 2 premolars, and 3 molars teeth in each half of a jaw. Thus, there are a total of 32 teeth in a human adult.


More About NCERT Exemplar Class 11 Biology Chapter 16

In a very systematic and well-structured way, the process of digestion of food is explained in NCERT Exemplar Class 11 Biology chapter 16 solutions and to add to it various chemical reactions which occur while digesting is explained in a simple and concise method for the better understanding of the students. The following set of solutions have been worked upon by professionals having immense knowledge of CBSE, NCERT, and the subject so that you get the best possible answers for the questions.

All of which are detailed in the NCERT Exemplar solutions for Class 11 Biology chapter 16 which by utilising the NCERT Exemplar Class 11 Biology chapter 16 Solutions PDF Download function students can make learning even more convenient as they will get access to quality study material effectively constructed by experts for the best learning experience.

NCERT Exemplar Class 11 Biology Chapter 16 Solutions - Major Subtopics

  • Digestive System
  • Alimentary Canal
  • Digestive Glands
  • Digestion of food
  • Absorption of digested products
  • Disorders of the digestive system

What will the students learn in NCERT Exemplar Class 11 Biology Chapter 16 Solutions?

As mentioned earlier, digestion is an important process in the bodies of every living organism as without this, humans or animals would either not exist or be a lot different than we are currently. The mention of the different chemical reactions for every breakdown process of food such as carbohydrates, proteins, fats has made the understanding of the chapter easier for the students.

In a table-like format, the summary of the absorption process has also been explained. Students who are interested in pursuing medicine must pay keen attention to this chapter as it is an essential aspect of the human bodies.

Keeping aside the examination point of view, it is always good and interesting to learn about the processes and functions that go on in our bodies which help us have a healthy life and be at ease. Knowing about the different types of digestive disorders will help them treat them with care and also handle medicines effectively, now and later in life when one pursues it.

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Important Topics - NCERT Exemplar Class 11 Biology Chapter 16 Solutions

  • Class 11 Biology NCERT Exemplar solutions chapter 16 has detailed that the digestive system, digestive glands, absorption of digested products(nutrients), digestive tract and disorders of the digestive system are important topics which students should pay extra attention to.
  • It also has fairly detailed and well-drawn diagrams to explain the functioning of the digestive system in human beings. NCERT Exemplar Class 11 Biology chapter 16 solutions, thus, provides a proper understanding of human physiology.
  • NCERT Exemplar Class 11 Biology chapter 16 solutions is designed to help students for their examinations, but it is a good resource material to refer to in other cases as well to enhance your knowledge or to get an expert opinion on something you are unclear on. Having accurate and detailed knowledge about the topics which are considered important from an examination point of view is important.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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