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Digestion and Absorption Class 11 – Introduction –
Digestion and Absorption Class 11:- Food is the basic requirement of living organisms. The components of food are proteins,fats and carbohydrates. In this chapter, we are going to study the process of digestion in details.The food provides energy for the growth and development of the organism.The biomolecules in the body cannot be used in original format ,they needs to be break down into simpler, absorbable forms .Let us study this in more details.
Digestion and Absorption Class 11 – Very Short Answer Type Questions
Q.1. What is the food called when food blends fully with acidic gastric juices of the stomach by the churning movements of the muscular wall?
A.1. Food stays in stomach for 4-5 hours during which it gets blended fully with acidic gastric juice present in stomach through the churning movements of muscular walls. At this point, the food is referred to as the chyme.
Q.2. The tissue or the cells that secrete enzyme the enterokinase, which activates the Trypsinogen. Explain in details how it is activated?
A.2. Enzyme enterokinase activates trypsinogen to the trypsin. It is secreted by the intestinal mucosa.
Q.3. In the alimentary canal where absorption of the water, alcohol and the simple sugars takes place?
A.3. It takes place in the wall of stomach.
Q.4. Name the enzymes that are involved in breakdown of the nucleotides into the bases and sugars.
A.4. These are nucleotidases and nucleosidases.
Q.5. What do u mean by digestion?
A.5. It is the process of converting the complex food substances into the simpler substances that can be absorbed through the mechanical and the biochemical methods.
Q.6. Name the type of teeth attachment to jawbones wherein the each tooth is embedded in the socket of the jawbones.
A.6. Type of teeth is known as Codont.
Q.8. Name the glands which are associated with alimentary canal?
A.8.The salivary glands, liver and pancreas, are lists of glands, associated with the alimentary canal.
A.9. Pancreas is an abdominal organ located in stomach, behind abdomen and surrounded by the spleen, liver and the small intestine. It is a vital part of human digestive system and is responsible for the regulation of the blood sugar levels.
Digestion and Absorption Class 11 Quiz
Q.10.What do u meant by Liver?
A.10. Liver is largest organ located in right upper quadrant of the abdomen and below diaphragm. It plays a vital role in digestion of the fats, metabolism of the carbohydrates and the formation of the bile.
Q.11.Write functions of bile?
A.11.The bile is the dark yellowish-green or the brown colour fluid produced by liver and stored within gallbladder. It comprises of the organic molecules such as the bile acids, salts, bilirubin and the cholesterol, and the water.
Q.12.Write in details the process of the elimination.
A.12.Elimination is the last process of the digestion. During this process, food residues that cannot be digested or absorbed are excreted or egested from body as the semi-solid faeces.
Q.13.What do u mean by Constipation?
A.13.Constipation means the digestive disorders, that are associated with the irregular and the difficult bowels movement that are characterized by the hardened faeces.
Q.14.The process of digestion takes place in ?
A.1. Process of digestion begins from mouth and is then carried on to stomach, to the small intestine, large intestine and then to anus.
Q.15.What do u mean by the Alimentary Canal?
A.15. Alimentary canal is pathway by which the food enters to our body. It is the tube-like structure, which starts from mouth and ends at large intestine.
Digestion and Absorption Class 11 – Short Answer Type Questions
Q.1. What do u mean by pancreas? Which are the main secretions of pancreas,which aids in the digestion process?
A.1. Pancreas is gland that has an endocrine and an exocrine parts required in producing the hormones and the digestive enzymes. The inactive enzymes involves in the digestion and secreted by the Pancreas are:
Q.2. Name the organs of human alimentary canal. Mention major digestive glands along with their locations in the body.
A.2. Alimentary canal consists of anterior openings – pharynx, buccal cavity, mouth, oesophagus, stomach, small intestine, large intestine, and the anus.
The digestive glands are:
The salivary glands – Saliva is produced by the three pairs of the salivary glands. These are which the 1.parotids (cheek), the submandibular or the sub-maxillary(lower jaw) and the sublingual gland (under tongue).
2.The pancreas – It is located between limbs of the C-shaped duodenum.
3.The liver – It is located in abdominal cavity, below diaphragm.
Digestion and Absorption Class 11 books
Q.3. What is the significance of gall bladder? Write about it’s consequence if it stops functioning or is removed.
A.3. Gall bladder is a pear-shaped sac-like the composition, which is connected to dorsal surface of liver via connective tissue. The hepatic cells of liver secrete bile, which moves through hepatic ducts gets accumulated in gall bladder.
If gall is removed or turns non-functional, the bile would continuously run from liver into small intestine, without being concentrated enough as bile originated in gall bladder. A low fat diet is suggested even though body adapts as the digestion of fat is seemingly decreased after the gall bladder is being removed.
Digestion and Absorption Class 11 Toppers Notes
Q.4. Name the three major types of the cells present in gastric glands. Name their secretions.
A.4. Gastric glands are present in mucosa of stomach. Three major cells are:
Cell Type Secretions
1.Mucous neck cells 1.Mucus
2.Chief or peptic cells 2.Proenzyme pepsinogen
3.Oxyntic or parietal cel 3.HC1 and intrinsic factor
Q.5. How is intestinal mucosa guarded against acidic food entering from the stomach?
A.5. Highly concentrated hydrochloric acid,HCl rich food is prevented from the excoriation because of mucus secreted by goblet cells along with bicarbonates, which are the significant in lubrication and the protection of mucosal epithelium.
Q6. Write differences between the digestion and the absorption?
A.6.Digestion is the process of crushing or digesting large and insoluble food molecules into smaller and soluble molecules for easy absorption into the bloodstream.
Absorption is mechanical and the digestive processes of absorbing or the assimilation of the substances into cells or across tissues and organs through the process of diffusion or osmosis process.
Q.7. Define the process of digestion and absorption of carbohydrates?
A.7. Carbohydrates consist of the monosaccharides, disaccharides and the complex carbohydrates, including the starch, glycogen, and fibre. The digestion and absorption process of carbohydrates begin with breakdown of disaccharides and the complex carbohydrates into the monosaccharides for the absorption, and the process begins from the in the mouth via the process of chewing and with release of the enzyme amylase from salivary glands. The digestion and absorption of carbohydrates are completed in small intestine, with help of enzyme amylase secreted by the pancreas.
The diagram explains process and the different enzymes involved in the process of digestion and absorption of carbohydrates.
Digestion and Absorption of Carbohydrates.
Q.8.Define digestion, mechanical digestion and chemical digestion?
*Digestion is a term that is associated with the process of converting the large insoluble food molecules into the small, soluble and the absorbable forms. This complete digestion process occurs in a sequential manner by the combination of both the methods:
*Mechanical digestion– Here the food is completely broken down into the very smaller fragments through some physical processes. These physical processes begins from the mouth to the stomach via act of chewing in the mouth, churning in stomach and the segmentation process in the small intestine.
*Chemical digestion – Here,the food is broken down by actions of chemical agents such as the acids, the bile and the enzymes.
Q.9.What do you mean by enzymes?
A.9. Enzymes can be defined as the biological molecules or biological catalysts, which significantly speed up the rate of digestion by lowering the activation energy. Enzymes facilitates the digestion of some of the molecules to occur independently, in the different locations, at the body temperatures and at sufficient speeds.
Q.10.What do u mean by indigestion?
A.10. Indigestion is also called Dyspepsia, is a medical term, which describes the pain and the discomfort in upper abdomen. It is a type of a functional disorder that is caused by abnormal functions of digestive system or the gastrointestinal organs.
Digestion and Absorption Class 11 – Long Answer Type Questions
Q.1. Write the changes occurring in the passage through the alimentary canal when a person has ingested roti and dal as part of his meal.
A.1. The following are the changes:
Teeth in mouth masticates the food particles, wherein the carbs i.e. the carbohydrates in the food are digested through actions of the enzyme secreted by the salivary gland “salivary amylase”.
Food at this specific stage is partially digested and reaches the stomach where the food is treated with the HCL i.e. acidic in nature. The proteins present in the food are digested through proteolytic enzymes.
Gall bladder secrets bile to digest the lipids present in the food particles.
The semi or partially digested food is finally digested in duodenum of the small intestine by actions of the digestive enzymes in pancreatic and the intestinal juices.
Small intestine of the alimentary canal absorbs the disintegrated food in form of glycerol, amino acids(AA),starch, etc after the digestion process.The food that is not digested in the finally eliminated from the system through anus at the end.
Q.2. Write the mechanism of the process absorption.
A.2. It is the phenomenon through which the end products of the digestion process passes through the intestinal mucosa into the blood or the lymph, which is carried out through the passive, active,or the facilitated transportation means. Through simple diffusion process,the little quantities of monosaccharides such as the amino acids, glucose and the few electrolytes such as chloride ions are absorbed. Concentration gradients decides how the passage of these substances takes place into the blood. But the amino acids and the glucose are being absorbed with the aid of carrier proteins and is known as the facilitated transport. Water transportation is dependant on osmotic gradient. Active transportation requires the energy as it takes place against concentration gradient.
Through this mechanism monosaccharides such as glucose, nutrients such as amino acids, electrolytes such as Na+,k+ are being absorbed into the blood vessels.
Q.3. Write the importance of the hepato-pancreatic complex in the digestion of the following -proteins, carbohydrates and the fats components of the food?
A.3. Pancreatic and the bile duct secretes the bile juice and the pancreatic juices into duodenum through a common duct which is known as the hepato-pancreatic duct, that is shielded by the “Sphincter of Oddi”. The pancreatic juices involves the inactive enzymes –
The hepato-pancreatic secretion effects the digestion of fats, proteins, and carbohydrates in the following way-
The hydrolysis of carbohydrates in the chyme into disaccharides by pancreatic amylase
Fats are disintegrated into diglycerides and monoglycerides by lipases along with the aid of bile
Proteolytic enzymes of the pancreatic juice act upon the proteins in the chyme that reach the intestine to produce proteases.
Q.4. How the digestion process occurs in the buccal cavity? Explain in details the arrangement of teeth.
A.4. Buccal cavity performs two important functions –
1. It masticates the food.
2.It facilitates swallowing of food.
3.The tongue and teeth with the aid of the saliva, masticate the food and blend the food completely.
The mucus present in the saliva helps in lubricating and holding the masticated food particles into a bolus. The bolus is further passed into the pharynx and down the oesophagus by deglutition or swallowing. The bolus is moved through the successive wave of the contractions of muscles deep down the oesophagus, this movement is known as peristalsis movement.
Digestion and Absorption Class 11 study materials
Q.5. Explain the following – Bolus, Mastication and Digestive Enzymes.
*Bolus – It is the round, ball-shaped and the mixture of the chewed food formed by combination of the food and the saliva in mouth or the alimentary canal.
*Mastication – It is act of chewing food. In the process of mastication, the food particles are broken down into the smaller and the soluble particles for ease of swallowing. This process occurs inside oral cavity, including teeth, tongue and cheek.
*Digestive Enzyme – They are group of enzymes found in the digestive tracts and are secreted predominantly by pancreas and other organs including salivary gland, stomach and in the lining of the gastrointestinal tract.
Digestive enzymes plays a key role in process of the chemical digestion.
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