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NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption

NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption

Edited By Irshad Anwar | Updated on Sep 08, 2023 01:27 PM IST

Digestion and Absorption | NCERT Solutions PDF

NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption: Everybody knows that food is one of the basic requirements of all living organisms. The major components of our food are carbohydrates, proteins, and fats. Vitamins and minerals are also required in small quantities. You know that food provides energy and organic materials for the growth and repair of tissues. Likewise so many important topics and concepts are in this chapter which you are going to study. NCERT Solutions have been updated to the latest CBSE Syllabus. NCERT Solutions for Class 11 is a great resource for students who have just started getting ready for the upcoming annual exams.

NCERT Solutions For Class 11 Biology Digestion and Absorption

In the solutions for NCERT Class 11 Biology Chapter 16 Digestion and Absorption you will get questions along with their answers and all will be related to the digestion and absorption of food in our body. In CBSE NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption, you will learn that biomacromolecules in food cannot be utilized by our bodies in their original form. They have to be broken down and converted into simple substances in the digestive system. This process of conversion of complex food substances to simple absorbable forms is called digestion. It is carried out by our digestive system by mechanical and biochemical methods. You are going to get questions related to this in NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption. If you are looking for an answer from any other chapter even from any other class then go with NCERT Solutions, there you will get all the answers including Digestion and Absorption Class 11 NCERT Solutions.

Biology Class 11: Digestion and Absorption NCERT PDF will help you in getting all the answers to digestion and absorption class 11 NCERT. As in this Chapter 16 - Digestion and Absorption of Human Physiology, you will also learn about the absorptions of digested food and the digested end products are absorbed into the body through the epithelial lining of the intestinal villi. and now the question is what about undigested food, so it enters into the caecum of the large intestine through the ileocecal valve, which prevents the backflow of the faecal matters. Check your knowledge and practice Digestion and Absorption Class 11 NCERT Questions and Answers.

After going through Digestion and Absorption NCERT, you must be able to understand the answers to all the following questions given in Digestion and Absorption Class 11 NCERT PDF:

NCERT Solutions For Class 11 Biology Digestion and Absorption - PDF Download

This chapter has been removed as per the latest update on the CBSE Syllabus 2023-24,

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NCERT Solutions for Class 11 Biology Chapter 16 - Digestion and Absorption (Solved Exercise)

The complete solution for Digestive System NCERT is given below:

Digestion and Absorption Class 11 NCERT Questions and Answers

Q1. Choose the correct answer among the following :

(a) Gastric juice contains

  • (i) pepsin, lipase and rennin
  • (ii) trypsin, lipase and rennin
  • (iii) trypsin, pepsin and lipase
  • (iv) trypsin, pepsin and renin

Answer:

Gastric juice contains pepsin, lipase and rennin. Pepsin is secreted as pepsinogen (inactivated), which is activated by HCI. Pepsin digests proteins into peptones. Lipase breaks down fats into fatty acids. Rennin is a photolytic enzyme present in the gastric juice. It helps in the coagulation of milk.

Q1. Choose the correct answer among the following :

(b) Succus entericus is the name given to (i) a junction between ileum and large intestine (ii) intestinal juice (iii) swelling in the gut (iv) appendix

Answer:

Correct option is ii. Intestinal juice. Succus entericus is another name for intestinal juice. It is secreted by the intestinal gland and it contains a variety of enzymes such as maltase, lipases, nucleosidases, dipeptidases, etc.

Q2. Match column I with column II :

Column I Column II
(a) Bilirubin and biliverdin (i) Parotid
(b) Hydrolysis of starch (ii) Bile
(c) Digestion of fat (iii) Lipases
(d) Salivary gland (iv) Amylases

Answer:

Correct matching is (a)- ii, (b)- iv, (c)- iii, (d)- i

Column I Column II
(a) Bilirubin and biliverdin (ii) Bile
(b) Hydrolysis of starch (iv) Amylases
(c) Digestion of fat (iii) Lipases
(d) Salivary gland (i) Parotid


NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption:

Q3. Answer briefly:

(a) Why are villi present in the intestine and not in the stomach?

Answer:

The Intestine is involved in the absorption of digested food. So, to increase the surface area of the absorption, villi are the present on the surface of the intestine. Villi are small finger-like structures. that increase the surface area of absorption of digested food into the blood.

Q3. Answer briefly:

(b) How does pepsinogen change into its active form?

Answer:

pepsinogen is a precursor of pepsin stored in the stomach walls. It is converted into pepsin by the action of hydrochloric acid. Pepsin is the activated form of pepsinogen.

Q3. Answer briefly:

(c) What are the basic layers of the wall of alimentary canal?

Answer:

The wall of the alimentary canal consists of four concentric layers. Beginning from the outside, these layers are visceral peritoneum, muscular coat, submucosa and mucosa.

Q3. Answer briefly:

(d) How does bile help in the digestion of fats?

Answer:

Bile refers to the digestive juice secreted by the liver and stored in the gallbladder. Bile juice has bile salts such as bilirubin and biliverdin. These break down large fat globules into smaller globules so that the pancreatic enzymes can easily act on them. This process is known as emulsification of fats. Bile juice also makes the medium alkaline and activates lipase.

Solutions for NCERT Class 11 Biology Chapter 16 Digestion and Absorption:

Q4. State the role of pancreatic juice in digestion of proteins.

Answer:

The pancreatic juice is secreted by the pancreas and it is a mixture of enzymes such as trypsinogen, chymotrypsinogen, and carboxypeptidases. These enzymes are inactive and they are required for the process of digestion of proteins.

The role of these enzymes in protein digestion is depicted below

1. Enzyme trypsinogen gets activated into trypsin by an enzyme called enterokinase. This enzyme is secreted by the intestinal mucosa. Trypsin further activates the other enzymes of pancreatic juice such as chymotrypsinogen and carboxypeptidase.

2. Chymotrypsinogen is a milk-coagulating enzyme that converts proteins into peptides.

3. Carboxypeptidase is an enzyme that acts on the carboxyl end of the peptide chain and helps in the release of the last amino acid from the polypeptide chain, thus, aiding protein digestion.

Q5. Describe the process of digestion of protein in stomach.

Answer:

Stomach is the first organ where the digestion of proteins starts while the small intestine is the part where protein digestion ends. Stomach possess gastric glands which secret gastric juices containing enzymes that act on food. Gastric juice mainly contains hydrochloric acid, pepsinogen, mucus, and rennin. Firstly, the food that enters the stomach becomes acidic when it mixes with the gastric juice. The function of these components in protein digestion is as follows:

1. Hydrochloric acid dissolves the food particle and creates an acidic medium inside the stomach. Acidic medium is a pre-requisite for the conversion of inactive enzyme pepsinogen into active pepsin. .

2. Pepsin is a protein-digesting enzyme that converts proteins into proteases and peptides.

3. Rennin which plays an important part in the coagulation of milk is a proteolytic enzyme which is released as prorennin i.e. inactive rennin.

Digestion and Absorption Class 11 NCERT Solutions

Q6. Give the dental formula of human beings.

Answer:

The dental formula refers to the arrangement of teeth in each half of the upper jaw and the lower jaw.

The dental formula for milk teeth in humans is:

Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, and 2 molars. Premolars are absent in milk teeth. It is represented as

2102/2102 \times 2 = 20

An adult human has 32 permanent teeth. Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, 2 premolars, and 3 molars. The dental formula for permanent teeth in humans represented as

2123/2123 \times 2 = 32

Q7. Bile juice contains no digestive enzymes, yet it is important for digestion. Why?

Answer:

The bile juice secreted by the liver does not contain any digestive enzymes, however, it plays an important role in the digestion of fats. It contains bile salts such as bilirubin and biliverdin which break down large fat globules into smaller globules. This makes sure that the pancreatic enzymes can easily act on the fat globules. This process is known as emulsification of fats. Bile juice also makes the medium alkaline and activates lipase. Hence, bile juice contains no digestive enzymes, yet it is important for digestion

CBSE NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption:

Q8. Describe the digestive role of chymotrypsin. Which two other digestive enzymesof the same category are secreted by its source gland?

Answer:

Chymotrypsinogen is an inactive enzyme that gets activated into chymotrypsin by the action of enzyme trypsin present in the pancreatic juice. Chymotrypsin, when activated plays an important role in the breakdown of the partially- hydrolysed proteins into peptides

The other digestive enzymes of the same category, are trypsinogen and carboxypeptidase. These are also secreted by the same source-gland, pancreas. Trypsinogen gets activated via enterokinase into trypsin.

Q9. How are polysaccharides and disaccharides digested?

Answer:

The process of digestion of carbohydrates occurs in the mouth and small intestine.

Digestion of carbohydrates in the mouth- After entering into the mouth, the food gets mixed with saliva which breaks down the starch into maltose, isomaltose and limit dextrins. Saliva contains an enzyme called salivary amylase which is involved in the break down of starch into its constituents at a particular pH of 6.8. This enzyme continues to act in the oesophagus, but its action stops in the stomach as the contents become acidic. Therefore, the carbohydrate-digestion stops in the stomach.

Digestion in the small intestine- In the small intestine, carbohydrate digestion resumes. The food is acted upon by pancreatic juice and the intestinal juice. Pancreatic juice contains the pancreatic amylase that hydrolyses the polysaccharides into disaccharides. On the other hand, intestinal juice contains a variety of enzymes (disaccharidases such as maltase, lactase, sucrase, etc.) which help in the digestion of disaccharides.

The digestion of carbohydrates is completed in the small intestine.

Class 11 Biology Chapter 16 Question Answer

Q10. What would happen if HCl were not secreted in the stomach?

Answer:

The function of hydrochloric acid in the stomach is to dissolve food particles and maintain an acidic medium. The acidic medium is required for the pepsinogen to be converted into pepsin which is essential for the process of digestion of proteins. Hence, if HCL were not secreted in the stomach, then pepsin would not be activated leading to impaired protein digestion.

Q11. How does butter in your food get digested and absorbed in the body?

Answer:

Butter is a fat-based product.

Digestion of fats

Fats are digested in the small intestine. The liver secretes bile juice which contains bile salts such as bilirubin and biliverdin. These break down large fat globules into smaller globules, to increase their surface area for the action of lipase. This process is called emulsification of fats. Later, the pancreatic lipase present in the pancreatic juice and the intestinal lipase present in the intestinal juice hydrolyse the fat molecules into triglycerides, diglycerides, monoglycerides, and finally into glycerol.

Absorption of fats

During the digestion of fats, the fats are broken down into fatty acids and glycerol. These are water-insoluble substances, hence, they cannot be directly absorbed by the blood. Therefore, they are first incorporated into small droplets called micelles and then transported into the villi of the intestinal mucosa. These are then converted into small microscopic particles called chylomicrons, which are small, protein-coated fat globules. These chylomicrons are transported to the lymph vessels in the villi. From the lymph vessels, the absorbed food is finally released into the bloodstream and from the bloodstream, to each and every cell of the body.

NCERT Solutions for Class 11 Biology Digestion and Absorption:

Q13. Explain the term thecodont and diphyodont.

Answer:

Thecodont: It refers to a type of dentition in which the teeth are embedded in the deep sockets of the jaw bone. This type of dentition is common in mammals.

Diphyodont: It refers to a specialised kind of dentition in which two successive sets of teeth are developed during the lifetime of the organism. The first set of teeth is deciduous and the other set is permanent. The deciduous set of teeth is replaced by permanent adult teeth. This type of dentition can be seen in humans.

Q14. Name different types of teeth and their number in an adult human.

Answer:

In an adult human, four different types of teeth are found. These include incisor, canine, premolar and molar teeth.

1. Incisors: The eight teeth in the front are incisors. There are four incisors each in the upper jaw and the lower jaw. The function of incisors is the cutting off food particles.

2. Canines: The pointy teeth on either side of the incisors are canines. They are four in number, two each placed in the upper jaw and the lower jaw. They are meant for tearing.

3. Premolars: These are the teeth next to the canines. They are eight in number, four each placed in the upper jaw and the lower jaw. Their function is grinding.

4. Molars: These are found at the end of the jaw, next to the premolars. There are twelve molars, six each placed in the upper jaw and the lower jaw.

Questions on Digestion and Absorption Class 11

Q15. What are the functions of liver?

Answer:

Functions of bile juice are as follows:

1. The liver secretes bile juice which plays an important role in the digestion of fats.

2. Conversion of poisonous ammonia to urea, to clear the blood of drugs and other poisonous substances

3. Conversion of excess glucose into glycogen for storage, which can later be converted to glucose for energy

Important Topics of NCERT Solutions for Class 11 Biology Chapter 16 - Digestion and Absorption

The important topics and subtopics of Class 11 Biology Digestion and Absorption Solutions are given below:

16.1 Digestive System

16.1.1 Alimentary Canal

16.1.2 Digestive Glands

16.2 Digestion of Food

16.3 Absorption of Digested Products

16.4 Disorders of Digestive System

NCERT Solutions for Class 11 Biology Chapter 16 – Digestion and Absorption

Unit 5 - Human Physiology is where - NCERT Solutions for Class 11 Biology - Digestion and Absorption is located. Students should pay extra attention to Digestion and Absorption NCERT because, based on past trends, it can be inferred that Unit 5 carries 18 marks, making up about 25% of the total weightage. If you have any queries in understanding Class 11 Biology Chapter 16 NCERT Solutions which are mentioned in the Digestion and Absorption Class 11 PDF, then again go through the NCERT Digestion and Absorption, then try to solve them by yourself. Then compare your solutions with the given Class 11 Biology Digestion and Absorption Solutions. All important concepts have been covered in the Digestion and Absorption Class 11 NCERT Questions and Answers

Ch 16 Biology Class 11 focuses on the vitally important processes of digestion and absorption in living things. Since all living things are made up primarily of major components like proteins, fats, and carbohydrates, food is one of our fundamental needs. Digestion and Absorption NCERT PDF will help you not only for your school exam but also in the preparation for other competitive exams like NEET as questions on digestion and absorption Class 11 appears in the exam frequently.

Highlights of NCERT Solutions for Class 11 Biology Chapter 16 – Digestion and Absorption

The key features of Class 11 Biology Digestion and Absorption Solutions are listed below:

  • Digestion and Absorption Class 11 NCERT Solutions are framed in accordance with the textbook data.
  • Class 11 Biology NCERT Solutions provide answers to all the questions of Class 11 digestion and absorption appearing in the same order as provided in the textbook.
  • Digestion and Absorption NCERT Solutions are the ultimate resources for all the academic requirements of students in the CBSE session.
  • The experienced subject experts at Careers360 crafted these Class 11 Biology Chapter 16 Question Answer.
  • Digestion and Absorption Class 11 Questions and Answers are provided in the most efficient and effective pattern.
  • The conceptual knowledge of students can be assessed while referring to Digestion NCERT.
  • NCERT Digestion and Absorption PDF are easily available in a ready-to-download format.

NCERT Solutions for Class 11 Biology: Chapter-wise

NCERT Solutions for Class 11: Subject-wise

Check the NCERT Books and NCERT Syllabus here:

Frequently Asked Questions (FAQs)

1. What are the benefits of digestion and absorption ncert pdf?

The benefits of NCERT Biology Class 11 digestion and absorption are given below: 

  • NCERT is the base of your learning.  
  • You will get all the answers to digestion and absorption class 11 ncert and it will help you to score good marks in the exam.  
  • Digestion and absorption class 11 ncert pdf will also help you with competitive exams like NEET.  
  • Digestion and absorption ncert will also help you in your 12th board exam.  
  • NCERT digestion and absorption will also boost your knowledge. 
  • To score well in the examination, follow the NCERT syllabus and solve the exercise given in the NCERT Book. To practice more problems, students must refer to NCERT Exemplar.

2. What are the important topics of digestion and absorption class 11 pdf?

The important topics of ch 16 biology class 11 are:

  • Digestive System  

  • Alimentary Canal  

  • Digestive Glands  
  • Digestion of Food  
  • Absorption of Digested Products  
  • Disorders of Digestive System
3. Why are villi present in the intestine and not in the stomach according to digestion and absorption 11 ncert?

The Intestine is involved in the absorption of digested food. So, to increase the surface area of the absorption, villi are the present on the surface of the intestine. Villi are small finger-like structures. that increase the surface area of absorption of digested food into the blood.

4. How does bile help in the digestion of fats according to digestive system pdf ncert?

Bile refers to the digestive juice secreted by the liver and stored in the gallbladder. Bile juice has bile salts such as bilirubin and biliverdin. These break down large fat globules into smaller globules so that the pancreatic enzymes can easily act on them. This process is known as emulsification of fats. Bile juice also makes the medium alkaline and activates lipase.

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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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