Nutrition and Digestion : 12th Class Biology Question Answer Lesson 13 - NIOS

Nutrition and Digestion : 12th Class Biology Question Answer Lesson 13 – NIOS

INTEXT QUESTIONS 13.1

List the five major steps in animal nutrition
Ans – Ingestion, digestion, absorption, assimilation, egestion
What is intracellular digestion? Give example of an organism showing intracellular digestion.
Ans. All the five steps of digestion occur inside the cell itself. Paramecium, Amoeba etc.

INTEXT QUESTIONS 13.2

Match the characteristics in column A with the parts of digestive system givenin column B
Column A Column B
Characteristics Part
(1) Common passage for air (a) Small intestine
breathed in and the food swallowed.
(2) Elastic bag like structure (b) Pancreas
(3) Has three limbs-ascending, (c) Duodenum
transverse and descending
(4) Longest part of the food canal (d) Pharynx
(5) Receives bile and pancreatic juice (e) Appendix
(6) Narrow worm-shaped projection (f) Stomach
(7) Largest gland in body (g) Colon
(8) Gland located in the bend of (h) Liverduodenum
Ans. 1. d, 2. f, 3. g, 4. a, 5. c, 6. e, 7. h, 8. b
Name the three salivary glands and mention their location in the mouth cavity.
Ans. Parotid – in front of and below ear
Submaxillary – inner side of lower jaw.
Sublingual – below the tongue

INTEXT QUESTIONS 13.3

How is grinding of food in the mouth helpful in digestion?
Ans. Smaller particles provide larger surface area for digestive action.
Name the source gland for following enzymes.
(i) amylase – salivary glands
(ii) pepsin – stomach
(iii) lipase – pancreas
List at least four enzymes that contribute towards digesting proteins.
Ans. Pepsin, Trypsin, Chymotrypsin, Carboxypeptidase.

INTEXT QUESTIONS 13.4

In which part of the alimentary canal does maximum absorption of water occur?
Ans. Colon/large intestine.
List any three ways in which the intestine increases the surface area forabsorption?
Ans. (i) very long (ii) villi (iii) microvilli
Which end products of digestion are absorbed by
(i) blood capillaries of intestinal villi?
Ans. Amino acids and simple sugars
(ii) Lacteals – fatty acids and glycerol

INTEXT QUESTIONS 13.5

Mention the source of secretion and the effect of the following:
(i) Gastrin – stomach, stimulates secretion of gastric juice
(ii) Enterogastrone – Duodenum, stops secretion of gastric juice.

INTEXT QUESTIONS 13.6

Name any three substances related to the blood, produced by liver.
Ans. Fibrinogen, prothrombin, heparin
List any three substances which the liver stores.
Ans. Sugar/glycogen, iron, vitamin A/D/B12
What happens to excess amino acids absorbed from gut ?
Ans. Broken down to produce sugar and urea, sugar is used and urea is excreted.

INTEXT QUESTIONS 13.7

(a) A doctor advises a person to sip ORS at regular intervals because he/shewas suffering from diarrheoa. What is this ORS?
Ans. Oral Rehydration Solution which is drinking water containing a pinch Plants and animalsof sugar and salt. Its consumption prevents dehydration.
(b) Name any one causative agent of diarrhoea in developing countires.
Ans. Rota virus / E.coli
(c) During the rainy season there is a rise in diarrhoea cases. What piece of advice will you give to your younger brother / sister to prevent oneself from getting diarrhoea?
Ans. Wash hands with soap and water before eating/wash raw vegetables well before cooking or consuming / cover food so that flies cannotsit on it / consume clear uncontaminated water.

A little girl/boy had a problem in passing stool. The faeces were dry and hard.The doctor said that this was because the child was not taking adequate amountof fibres in the diet and was not taking proper diet at proper time. What is this child suffering from?
Ans. Constipation
What is dyspepsia? What are its symptoms?
Ans. Indigestion or upset stomach. Symptoms–Stomach pain
Which organ of the body is involved in jaundice and how can you make out
that a person is suffering from jaundice.
Ans. Lever; urine and eyes look yellow.

TERMINAL EXERCISES

Explain the term “autotrophs”. How are animals different from plants with
regard to their mode of nutrition?
Enlist at least ten organs of the alimentary canal of man.
Define the term “digestion”. List the digestive processes occurring in the smallintestine.
How does digestion of carbohydrates and proteins take place in humans?
Explain the role of the following in the digestive process in humans :
(a) Gastrin (b) Hydrochloric acid (c) Secretin
Write short notes on
(a) absorption of the digested food (b) assimilation
(c) defaecation (d) role of liver in metabolism
Name the enzymes concerned with the digestion of various carbohydrates, the
region of the gut where they act and their products in the table given below:
Carbohydrate Enzyme Region of gut Product
Starch …………. …………. ………….
Dextrin …………. …………. ………….
Maltose …………. …………. ………….
Sucrose …………. …………. ………….
Lactose …………. …………. ………….
Bile has no digestive enzyme yet it plays a key role in digestion. What is its role?
Draw a well labelled diagram of alimentary canal in humans.
List common digestive disorders. Add a note on ORS.

NIOS 12th class biology Q Ans

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