Important Questions Class 11 Biology Chapter 16

Class 11 Biology Chapter 16 Important Questions – Digestion and Absorption

Biology shapes our understanding of the human body and who we are. The framework of our existence and evolution is provided by Biology. It enhances our comprehension of the biological world and the working of our bodies. The sixteenth Chapter of Class 11 Biology is digestion and absorption. Digestion is essential because our body needs nutrition from the food we consume. We must maintain an appropriate diet, drink adequate water, exercise and stay healthy.

Chapter 16 Class 11 Biology important questions discuss the various concepts revolving around the process of digestion and absorption. Digestion and absorption are crucial for competitive examinations like NEET, MH- CET, and board examinations. Students should have regular practice solving NCERT exercises and exemplar questions to develop a better understanding of the concepts so that they can answer any challenging question in the examination..

Biology requires  a lot of effort to memorise the various scientific names and biological concepts. Students may  find it hard to memorise it all at once. Hence studying Biology requires constant revision , memorisation by writing answers and timely action to resolve all your queries. The experienced Biology subject matter experts  at Extramarks have curated  important questions in Class 11 Biology Chapter 16 using NCERT Textbook, NCERT Exemplar, reference books, past year question  papers, and other sources. To assist students in comprehending each chapter, our Biology faculty has compiled a list of step-by-step solutions to the questions mentioned in the important questions Class 11 Biology Chapter 16. Students are advised to register with Extramarks and access these Class 11 Biology Chapter 16 important questions as per their convenience. 

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Get Access to Important Questions of Digestion and Absorption Class 11 for the Academic Year 2022-23.

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Important Questions Class 11 Biology Chapter 16 With Solutions

The chapter elaborates on various topics like the various parts included in the digestive system, such as the mouth, pharynx, stomach, large intestine, small intestine, rectum, Histology of the alimentary canal that includes serosa, muscular as, submucosa and mucosa, descriptions of the salivary glands, liver and pancreas, the process of food digestion and absorption, the disorder of the digestive system like jaundice, vomiting, constipation, diarrhoea, indigestion etc. Solutions to the Important Questions Class 11 Biology Chapter 16 cover all these crucial concepts with explanations. 

Given  below is the list of Important Questionnaires for Class 11 Biology Chapter 16, along with step-by-step solutions:

Question 1. Define the following terms:

1. Bolus.
2. Mastication.
3. Digestive Enzymes.

Answer 1: 

Bolus: Bolus is a round, ball-shaped mixture. Chewing helps to reduce the size of food particles to a size readily swallowed. As we chew, the salivary glands secrete saliva to ease the process of digestion. Saliva adds digestive enzymes, water and mucus that help to reduce food particles chemically. The saliva lubricates the food and eases the process of swallowing it down. Bolus is a mixture of chewed food formed by a combination of food and saliva in the mouth or alimentary canal.

Mastication: Mastication is the act of chewing food. It is the process of grinding, chewing and shredding food by the teeth. During this process, the food particles are broken down into smaller and soluble particles for easy swallowing. This process occurs inside the oral cavity, including the teeth, tongue and cheek.

Digestive Enzymes: Digestive enzymes are a group of enzymes that help digest complex food materials into simpler molecules for absorption by the body. During the digestion of food, various parts of the alimentary canal produce different digestive enzymes that help in the digestion of different components of food. Digestive enzymes are found in the digestive tract and are secreted predominantly by organs like the pancreas, including the salivary gland, stomach and gastrointestinal tract lining. 

For example, saliva produces digestive enzymes like salivary amylase that digests the starch. The stomach contains gastric glands that produce pepsin which helps in protein digestion. Apart from this, other enzymes such as trypsin and chymotrypsin also help in protein digestion. Digestive enzymes play a vital role in the process of chemical digestion.

Question 2. Write the mechanism of absorption.

Answer 2: The phenomenon in which the end products of digestion go through the intestinal mucosa into the lymph or blood is called absorption. Absorption is carried out either through active, passive or facilitated transport mechanisms.

Simple Diffusion: In simple diffusion, small amounts of monosaccharides, amino acids, and a few electrolytes such as chloride ions are absorbed. The above substances’ passage in the blood depends on the concentration gradient.

Facilitated Transport:  Compounds like fructose, as well as some amino acids, are absorbed with the help of a few carrier ions like Na+. This method is known as facilitated transport. Water transport is dependent on the osmotic gradient. 

Active transport: Active transport is the biological process of molecules moving against the concentration gradient. Hence, it requires chemical energy to transport the components from a lower to a higher concentrated area or body part. Through this mechanism, several monosaccharides like glucose, nutrients such as amino acids, and electrolytes such as Na+ are absorbed into the blood.

Passive transport: Passive transport is a biological procedure of moving molecules across cell membranes and tissues. Passive transport is a natural phenomenon. It does not require any external energy.

Transport of fatty acids and glycerols: Fatty acids and glycerols are not absorbed into the blood as these substances are insoluble. They are converted into tiny droplets; called micelles. These micelles move into the intestinal mucosa. These micelles in the intestinal mucosa get converted into tiny protein-coated globules known as chylomicrons. These chylomicrons are then transported into the lymph vessels in the villi. In the end, the lymph vessels finally release them into the bloodstream. 

Learn more about the absorption mechanism in important questions Class 11 Biology Chapter 16, available on the Extramarks website. These questions ensure that even the minutest doubt is resolved and the students develop an interest in learning and mastering the topic with ease.

Question 3. Bile juice contains no digestive enzymes, yet it is important for digestion. Why?

Answer 3: Bile is a digestive juice secreted by the liver. Bile juice is essential for digestion. Although it does not have any digestive enzymes, it plays an important role in the digestion and absorption of fats. The two bile salts present in bile are bilirubin and biliverdin. Bilirubin and biliverdin perform the role of breaking down large fat globules into smaller globules. After fat globules are broken down and converted into simpler compounds, they can be quickly acted upon by pancreatic enzymes. This phenomenon is known as the emulsification of fats. The bile juice is also known to make the medium alkaline and plays a role in activating the enzyme lipase.

Question 4. What are the functions of the liver?

Answer 4: The liver is the largest internal organ in the human body. The liver performs multiple vital functions for the body. It produces several enzymes required by the human body for normal functioning. It breaks down and detoxifies the substances in the blood and acts as a storage unit for many enzymes necessary for performing various vital functions. These functions include the maintenance of fluid within the circulatory system and blood clotting. The liver is also primarily responsible for the production of cholesterol and triglycerides. The liver also secretes components like carbohydrates, which are responsible for converting glucose to glycogen, stored in the liver and muscle cells. The liver also produces bile which aids food digestion. The liver plays a crucial role in removing toxins from the body. The toxins are flushed out by converting ammonia, a byproduct formed after the process of metabolism in the body is completed. It converts into urea, excreted through urine primarily produced by the kidneys. 

The liver is crucial in lymph formation. The liver produces an anticoagulant called heparin. The liver secretes red blood cells in an embryo. The liver secretes angiotensinogen, a protein known to aid the kidney in maintaining the body’s fluid and water content. It is also responsible for isolating excessive sugar from the blood and accumulating it in cells in the form of glycogen. This phenomenon is called glycogenesis, facilitated by the pancreatic hormone insulin. 

The liver is responsible for breaking down several medications, drugs and alcohol consumed by a person. It is also responsible for cleaving the hormone insulin and other hormones secreted by the body. The liver stores essential vitamins and enzymes that the body requires. These vitamins include vitamin A, D, folic acid, vitamin B12, vitamin K, and iron. Learn more about the liver and its functions through various study resources other than Biology Class 11 Chapter 16 important questions, all at Extramarks.

Question 5. Explain the digestion process in the buccal cavity with a note on the arrangement of teeth.

Answer 5: The buccal cavity primarily performs two significant functions. One is the chewing of food, and the other is the facilitation of swallowing. The food we eat gets mixed with saliva and forms a bolus. The saliva lubricates the food during the chewing process and breaks down food into smaller pieces. The buccal cavity is also involved in the digestion of similar food components. Digestion of carbohydrates begins in the buccal cavity. The food gets mixed with saliva containing salivary amylase. Salivary amylase converts starch into maltose, isomaltose and α-dextrins. Almost 30% of the starch present in the food is hydrolysed in the buccal cavity. Saliva does not have any protein or fat digesting enzyme. Therefore, digestion of protein and fats does not occur in the buccal cavity but in the alimentary canal’s latter part.

The oral cavity consists of several teeth and a muscular tongue. In humans, each tooth is embedded in the socket of the jaw bone. This type of attachment is termed the codont. Humans have two sets of teeth, a temporary and a permanent set. This type of denotation is called diphyodont. There are mainly four types of teeth in human beings – incisors, canines, premolars and molars. They are denoted as I, C, PM and M, respectively. In both halves of the upper and lower jaw, the arrangement of teeth follows the order I, C, PM, and M. The dental formula in humans is as 2123/2123, two incisors, one canine, two premolars and three molars on each side of jaws. Therefore, there are a total of 32 teeth in an adult human.

Question 6. How are the activities of the gastrointestinal tract regulated?

Answer 6: The activities of the Gastrointestinal Tract (GIT) are under neural and hormonal control for proper coordination among the different body parts. The gastrointestinal tract is innervated by many intrinsic nerves as well as by extrinsic nerves. These nerves help in the coordinated functioning of different parts of the alimentary canal. The intrinsic neural system, also named the enteric neural system, consists of: 

(i) Meissner’s plexus is located in the submucosa.

(ii) Auerbach’s plexus is situated in the muscular layer. 

The enteric neural system controls many gastrointestinal functions like secretion and motility. The extrinsic innervation of the gut consists of parasympathetic and sympathetic nerves, which can modify the activity of the intrinsic neural system in response to reflex activity initiated by GIT or from other body parts. 

The various senses like sight, smell and the presence of food in the oral cavity can stimulate saliva secretion through the vagus nerve. Neural signals also stimulate gastric and intestinal secretions. The muscular activity of various parts of the alimentary canal can also be moderated by neural mechanisms, both local and through CNS. Hormonal control for digestive juice secretions is done by the local hormones produced by the gastric and intestinal mucosa. These hormones include gastrin, which stimulates the release of gastric juice, enterogastrone, which inhibits gastric secretion and motility, secretin, which decreases gastric secretion, Vuorinen, which stimulates Brunner’s gland, etc.

Benefits of Solving Important Questions Class 11 Biology Chapter 16

Biology is difficult to comprehend biological systems and digestive processes . After reading and solving exercises regularly, students can prepare well for exams.  Students from Class 1 to Class 12 can register themselves  on Extramarks website.  They can access the study materials designed by our Biology faculty experts. Students can revise and solve questions from different chapters using our wide range of study materials. This will help build conceptual knowledge and help you score well in exams.

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