digestion and absorption solutions class 11 CBSE NCERT

 digestion and absorption solutions class 11 CBSE NCERT 

Q1. 

a-(iv)

       b- (ii)

Q2. 

 column I            column II

         a                           ii

          b                          iv

          c                           iii

           d                         i

Q3.

 (a) villi are the finger-like projections present on the surface of the small intestine which increases in surface area for absorption.  it is mainly present in the small intestine not in the stomach as in our small intestine, the complete digestion takes place, all the secretions are made into this intestine. so to increase surface area for digestion and proper digestion for food, the villas are required in the small intestine.

    (b) the proteolytic proenzyme pepsinogen is an inactive enzyme that is responsible for the breakdown of proteins in the stomach, secreted by peptic cella or chief cells in the stomach. this enzyme is converted into its active form with the help of hydrochloric acid or HCl into pepsinogen. which further breakdown proteins into peptones and proteases.

     (c) the basic layers present in the alimentary canal are four different layers called serosa, muscular, mucosa, sub-mucosa, etc. these are layers of our digestive system which undergoes many functions related to absorptions and secretions and their actions.

      (d) the bile juice is secreted by bile ducts, which contains biliverdin, bilirubin, bile salts, cholesterol, and no enzymes as they are breakdown fats into small micelles. they are responsible for the emulsification of fats easily . it is also digested by lacteals in which these smaller micelles are broken down into chylomicrons so that it can be easily digested and provide us nutrition.

Q4

. the pancreatic juice plays a major role in the breakdown of proteins into amino acids, as they secrete trypsinogen, chymotrypsinogen, procarboxypeptidases, lipases, nucleases, amylases, etc. the uses all secretions made by the pancreas are all in their inactive forms, the trypsinogen changes into trypsin by the enzyme enterokinase, which in turn activates all the other enzymes further for a breakdown of proteins. the proteins from the stomach come in form of proteoses and peptones, the pancreatic juice converts them into dipeptides, which turn them into amino acids by dipeptidases. 

Q5. 

in the stomach, proteins are breakdown by pepsinogen into peptones, and proteases, then in the small intestine, further the proteins convert them into dipeptides, the further dipeptides converts by dipeptidase into amino acids finally which is complete digestion of proteins.

Q6

.the dental formula in the case of human beings is 2123 /2123.

Q7.

 bile contains no enzyme but then also it is very responsible for digestion as it is very important for the emulsification of fats in the stomach with the help of enzyme lipase. it contains biliverdin, bilirubin, lipases, cholesterol, and no enzymes.

Q8.

 (first part of the answer would be in Q4. the same answer ) 

(ii) procarboxypeptidases, chymotrypsinogen, lipases, nucleases, amylases, etc.(any two you can write).

Q9.

 the polysaccharides which are starch is digested from salivary amylase which has pH 6.4, that converts into di/monosaccharides (maltose ), this has many forms like maltose which converts by maltase into glucose, the other form is sucrose which converts by sucrase into glucose and fructose, the other which lactose which converts into glucose and galactose. hance, this is the simplest breakdown of carbohydrates into glucose.

Q10

. if HCL stops its secretions, it can lead to certain problems in our stomach:- 

•  the food would not be properly digested into the stomach and 
• provide nutrition to the body, 
• the proteins which are converted by pepsinogen would be left undigested and would not be digested,
•  the acids also kill certain germs and bacteria which can't live in such acidic pH of the body, when it stops secreting, the food would be full of germs and bacteria. 

Q11. 

 butter is a kind of fat, with the help of lipase, the polyglycerides into mono or diglycerides which inturn changes into fatty acids and glycerol.

Q12. 

same as Q4answer, but add this line before this answer (  in our stomach, the proteins are broken down pepsinogen into peptones and proteoses .). 

 

Q13.

thecodont - this is the type of dentition which, when the tooth is embedded in the socket jaw bone and this attachment is called thecodont.

      diphyodont - this type of dentition is when the milk temporary teeth are to be converted into permanent adult teeth.

Q14. 

the different types of teeth are molars, premolars, incisors, and canines, etc. there are 32 teeth in adult human beings.

Q15. 

being the largest gland of the body, the liver secretes bile juice which is especially for the digestion of fats into smaller micelles, it is around 1.2 to 1.5 kg weight of gland. this is the gland that is responsible for digesting fats in our body.