NCERT Solutions for Class 11 Biology Chapter 16
NCERT Solutions for Class 11 Biology Chapter 16 Digestion and Absorption to Study online or free to download in PDF updated for new session 2020-2021 useful for UP Board, CBSE, MP Board, Gujrat board, etc.Download Offline Apps based on latest NCERT Solutions in updated format for the this academic session. Ask your queries in Discussion Forum as well as help the others by answering their queries.
NCERT Solutions for Class 11 Biology Chapter 16
|Chapter 16:||Digestion and Absorption|
Class 11 Biology Chapter 16 Solutions in English
NCERT Solutions for Class 11 Biology Chapter 16 in PDF form to free download is given below updated for new academic session 2020-2021. Download NCERT Books 2020-21 following the latest CBSE Syllabus. Offline Apps are also based on latest NCERT Solutions. If you have doubts, visit to discussion forum and ask your doubts.
Important Notes on Digestion and Absorption
1. Peristalsis: The involuntary movement of the gut by which the food bolus is pushed forward.
2. Deglutition: The process of swallowing of food bolus. It is partly voluntary and partly involuntary.
3. Ruminants: The herbivores animals (e.g., cow, buffalo etc.) which have symbiotic bacteria in the human of their stomach which synthesize enzymes to hydrolyse cellulose into monosaccharides.
4. Diarrhoea: The abnormal frequent discharge of semisolid or fluid faecal matter from the bowel.
5. Vomiting: The ejection of stomach contents through the mouth, caused by antiperistalsis.
6. Dysentery: Frequent watery stools often with blood and mucus and with pain, fever and causes dehydration.
DIFFERENT TYPES OF TEETH
1. Canine – for tearing
2. Incisors – for cutting
3. Premolars – for grinding
4. Molars – for churning and grinding
Basic Steps of Holozoic Nutrition
1. Ingestion: Intake of food.
2. Digestion: Breaking down of complex organic food materials into simpler, smaller soluble molecules.
3. Absorption and assimilation: Absorption of digested food into blood or lymph and its use in the body cells for synthesis of complex components.
4. Egestion: Elimination of undigested food as faeces
Important Terms related to Chapter 16
1. Chyme: The semifluid mass into which food is converted by gastric secretion and which passes from the stomach into the small intestine.
2. Gastric: Anything associated with stomach is given a prefix – gastric.
3. Proenzyme: The inactive forms of enzymes.
4. Sphincter: A flap like structure at various junctions of the alimentary canal which facilities one way traffic in the alimentary canal.
5. Bolus: The masticated food mixed with saliva.
6. Digestion: The process in alimentary canal by which the complex food is converted mechanically and biochemically into simple substances suitable for absorption and assimilation.
7. Food: A substance which on taken and digested in the body provides material for growth, repair, energy, and reproduction, resistance from disease or regulation of body processes.
8. Thecodont: The teeth embedded in the sockets of the jaw bone, e.g., in mammals.
Important Questions on 11th Biology Chapter 16
Within these villi, there are numerous blood vessels that absorb the digested products of proteins and carbohydrates, carrying them to the blood stream. The villi also contain lymph vessels for absorbing the products of fat-digestion. From the blood stream, the absorbed food is finally delivered to each and every cell of the body.
(i) Serosa is the outermost layer of the human alimentary canal. It is made up of a thin layer of secretory epithelial cells, with some connective tissues underneath.
(ii) Muscularis is a thin layer of smooth muscles arranged into an outer longitudinal layer and an inner circular layer.
(iii) Sub-mucosa is a layer of loose connective tissues, containing nerves, blood, and lymph vessels. It supports the mucosa.
(iv) Mucosa is the innermost lining of the lumen of the alimentary canal. It is mainly involved in absorption and secretion.
The main components of gastric juice are hydrochloric acid, pepsinogen, mucus, and rennin. Hydrochloric acid dissolves the bits of food and creates an acidic medium so that pepsinogen is converted into pepsin. Pepsin is a protein- digesting enzyme. It is secreted in its inactive form called pepsinogen, which then gets activated by hydrochloric acid. The activated pepsin then converts proteins into proteases and peptides.
Rennin is a proteolytic enzyme, released in an inactive form called prorennin. Rennin plays an important role in the coagulation of milk.
The dental formula for milk teeth in humans is:2102/2102×2=20
Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, and 2 molars.
Premolars are absent in milk teeth.
The dental formula for permanent teeth in humans is:2123/2123×2=32
Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, 2 premolars, and 3 molars. An adult human has 32 permanent teeth.
Therefore, if HCl were not secreted in the stomach, then pepsin would not be activated. This would affect protein digestion. A pH of about 1.8 is necessary for proteins to be digested. This pH is achieved by HCl.
Examples include living crocodilians and mammals.
Diphyodont is a type 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 the permanent adult teeth. This type of dentition can be seen in humans.
The eight teeth in the front are incisors. There are four incisors each in the upper jaw and the lower jaw. They are meant for cutting.
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.
They are present next to the canines. They are eight in number, four each placed in the upper jaw and the lower jaw. They are meant for grinding.
They are present 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.
Hence,the dental formula in humans=2123/2123×2=32
This means each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, 2 premolars, and 3 molars. Hence, an adult human has 32 permanent teeth.