Lesson: Nutrition in Animals

Given below from (i) to (iv) are some food items.

(i) Boiled and mashed potato

(ii) Glucose solution

(iii) A slice of bread

(iv) Mustard oil

Which of the above will give blue-black colour when tested with iodine?

(a) (i) and (ii)

(b) (i) and (iii)

(c)(ii) and (iii)

(d) (iii) and (iv)

(b)

Which of the following pair of teeth differ in structure but are similar in function?

(a)canines and incisors.

(b)molars and premolars.

(c)incisors and molars.

(d)premolars and canines.

(b)

Read carefully the terms given below. Which of the following set is the correct combination of organs that do not carry out any digestive functions?

(a)Oesophagus, Large Intestine, Rectum

(b)Buccal cavity, Oesophagus, Rectum

(c)Buccal cavity, Oesophagus, Large Intestine

(d) Small Intestine, Large Intestine, Rectum

(a)

The swallowed food moves downwards in the alimentary canal because of

(a) force provided by the muscular tongue.

(b) the flow of water taken with the food.

(c) gravitational pull.

(d) the contraction of muscles in the wall of food pipe.

(d)

The acid present in the stomach

(a) kills the harmful bacteria that may enter along with the food.

(b) protects the stomach lining from harmful substances.

(c) digests starch into simpler sugars.

(d) makes the medium alkaline.

(a)

The finger-like outgrowths of Amoeba helps to ingest food. However, the finger-like outgrowths of human intestine helps to

(a) digest the fatty food substances.

(b) make the food soluble.

(c) absorb the digested food.

(d) absorb the undigested food.

(c)

Read the following statements with reference to the villi of small intestine.

(i) They have very thin walls.

(ii) They have a network of thin and small blood vessels close to the surface.

(iii) They have small pores through which food can easily pass.

(iv) They are finger-like projections.

Identify those statements which enable the villi to absorb digested food.

(a) (i), (ii) and (iv)

(b) (ii), (iii) and (iv)

(c) (iii) and (iv)

(d) (i) and (iv)

(a)

The false feet of Amoeba are used for

(a) movement only.

(b) capture of food only.

(c) capture of food and movement.

(d) exchange of gases only.

(c)

The enzymes present in the saliva convert

(a) fats into fatty acids and glycerol.

(b) starch into simple sugars.

(c) proteins into amino acids.

(d) complex sugars into simple sugars.

(b)

Cud is the name given to the food of ruminants which is:

(a) swallowed and undigested.

(b) swallowed and partially digested.

(c) properly chewed and partially digested.

(d) properly chewed and completely digested.

(b)

Choose the correct order of terms that describes the process of nutrition in ruminants.

(a) swallowing → partial digestion → chewing of cud →complete digestion

(b) chewing of cud → swallowing → partial digestion →complete digestion

(c) chewing of cud → swallowing → mixing with digestive juices → digestion

(d) swallowing → chewing and mixing → partial digestion→ complete digestion

(a)

Cellulose-rich food substances are good source of roughage in human beings because

(a) human beings do not have cellulose-digesting enzymes.

(b) cellulose gets absorbed in the human blood and converts into fibres.

(c) the cellulose-digesting bacteria convert cellulose into fibres.

(d) cellulose breaks down into smaller components which are egested as roughage.

(a)

Name the parts of the alimentary canal where

(i) water gets absorbed from undigested food.

(ii)digested food gets absorbed.

(iii)taste of the food is perceived.

(iv) bile juice is produced.

(i) Large intestine

(ii) Small intestine

(iii) Tongue

(iv) Liver

Mark the following statements as True or False. If false, write the correct statements.

(a)   Tongue is attached to the roof of the mouth cavity at the back.

(b)   The large intestine is longer and wider than the small intestine of the human alimentary canal.

(c)   Mucus protects the stomach lining from damage.

(d)   All heterotrophs have a similar basic process of nutrition.

(a)   False $–$ Tongue is attached at the back, to the floor of the mouth cavity.

(b)   False $–$ The large intestine is shorter with a larger lumen (wider) than the small intestine of the human alimentary canal.

(c)   True

(d)   True

Choose the odd one out from each group and give reasons.

(i) liver, salivary gland, starch, gall bladder

(ii) stomach, liver, pancreas, salivary gland

(iii) tongue, absorption, taste, swallow

(iv) oesophagus, small intestine, large intestine, rectum

(i) Starch. Rest all are glands.

(ii) Stomach. Rest are digestive glands.

(iii) Absorption. Rest are associated with the mouth.

(iv) Small Intestine. Rest are organs where no digestion takes place.

You were blindfolded and asked to identify the drinks provided in two different glasses. You could identify drink A as lime juice and B as bitter gourd juice. How could you do it in-spite of being blindfolded?

Tastes can be differentiated even while not seeing the food that is being eaten. This is owing to the presence of taste buds in the tongue that can identify separate food items, based on their taste.

Fill in the blanks with suitable words:

(a)   The alimentary canal stretches from _________to ______________.

(b)   Teeth are rooted in separate __________ in between the ________.

(c)   Digestion of food starts in __________ and gets completed in __________.

(d)   ____________is the largest gland in the human body.

(a) Mouth, anus

(b) Sockets, gums

(c) Buccal cavity, small intestine

(d) Liver

Following statements describe the five steps in animal nutrition.

Read each statement and give one word for each statement.

Write the terms that describes each process.

(a) Transportation of absorbed food to different parts of body and their utilisation.

(b) Breaking of complex food substances into simpler and soluble substances.

(c) Removal of undigested and unabsorbed solid residues of food from the body.

(d) Taking food into the body.

(e) Transport of digested and soluble food from the intestine to blood vessels.

(a) Assimilation

(b) Digestion

(c) Egestion

(d) Ingestion

(e) Absorption

Match the animals in Column I with their mode of feeding listed in Column II.

(a) iii

(b) i

(c) iv

(d) ii

Boojho took some grains of boiled rice in test tube ‘A’ and Paheli took boiled and chewed rice in test tube ‘B’. Both of them poured 1 $–$ 2 drops of iodine solution into the test tube and observed the colour change. What colour change would they have observed? Give reasons for your answer.

Test tube A: The colour will change to blue black because boiled rice contains starch.

Test tube B: The colour will not change because in boiled and chewed rice the starch has been turned into sugars after partial digestion.

A’ got her gall bladder removed surgically as she was diagnosed with stones in her gall bladder. After the surgery, she faced problems in digestion of certain food items when consumed in bulk. Can you tell which kind of food items would they be and why?

There will be digestion problems with foods containing fat. This is because the gall bladder stores bile juice that helps in fat digestion. Without the gall bladder, the bile juice produced by the liver will not get stored, and without the bile juice A will face difficulties in digesting fatty substances.

Match the organs in Column I with the words listed in Column II.

(a) iv

(b) v

(c) i

(d) iii

(e) ii

Ruminants such as cows and buffaloes swallow their food hurriedly and then sit restfully and chew their food. Can you reason why?

They sit restfully and chew cud which is the partially digested food. They do this to digest the food completely.

Boojho and Paheli were eating their food hurriedly so that they could go out and play during the recess. Suddenly, Boojho started coughing violently. Think of the reasons why he was coughing and discuss with your friends.

Sometimes, when eating in a hurry, or while talking and laughing during swallowing food, the epiglottis remains open, Epiglottis is a flap like valve at the opening of the windpipe. When the food enters the wind pipe owing to the open epiglottis, then coughing occurs where the food is forcibly thrown up, helping to clear the windpipe. Boojho started coughing violently because of this reason.

Fill in the blanks using the words listed below.

water, front, intestinal, salts, pseudopodia, back, vacuole

(a) The digestion of all food components is completed by the ____________ juice.

(b) Large intestine absorbs ___________ and some __________from the undigested food.

(c) Tongue is attached at the _____________ to the floor of the mouth cavity and is free at the _____________.

(d) Amoeba pushes out _____________ around the food and traps it in a food _____________.

(a) Intestinal

(b) Water, salts

(c) Back, front

(d) Pseudopodia, vacuole

Label the figure below as directed in (i) to (iv) and give the name of each type of teeth.

(i) The cutting and biting teeth as ‘A’

(ii) The piercing and tearing teeth as ‘B’

(iii) The grinding and chewing teeth as ‘C’

(iv) The grinding teeth present only in adult as ‘D’

A = Incisors

B =Canines

C = Premolars

D= Molars

Read the following passage carefully and answer the questions that follow it.

Bile juice is stored in a sac called, gall bladder, located near its organ of secretion, liver. The gall bladder releases the bile juice into the small intestine whenever food reaches there. Though bile juice is devoid of any digestive enzymes, it is required for the digestion of fats. The fats cannot be digested easily because they are insoluble in water and are present as large globules. Bile juice breaks down big fat droplets into smaller droplets. These are then easily digested by the enzymes released from the pancreas.

(a) Which organ secretes the bile juice?

(b) Why is digestion of fats difficult as compared to that of other nutrients?

(c) How does bile juice help in digestion of fat?

(d) Where is the digestion of fat completed?

(e) Does bile juice digest fat completely?

(a) Liver secretes bile juice.

(b) Fats are difficult to digest because they are insoluble in water.

(c) Bile juice helps in fat digestion by breaking down the big fat droplets into smaller ones, which makes it easier for the pancreatic juices to digest them.

(d) Digestion of fat is completed in the small intestine.

(e) No, bile juice does not digest fat completely, and helps in the breaking down of fat into smaller droplets only.

Label the following parts in Figure and name them.

(a) The largest gland in our body.

(b) The organ where protein digestion starts.

(c) The organ that releases digestive juice into the small intestine.

(d) The organ where bile juice gets stored.

(a)   Liver

(b)   Stomach

(c)   Pancreas

(d)   Gall bladder                    

Open your mouth, look into a mirror and try to count the different types of teeth in your mouth. Compare them with Figure 2.3 on page 13 of your NCERT textbook. Record your observations in the table below:

(a)   Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?

(b)   Compare the number and type of teeth in an adult (say your parents or cousins who have reached the age of 25$–$30 or more). Note your observation.

Children have 28 teeth, comprising of two molars in each jaw. Adults on the other hand have six molars in each jaw, hence the difference in number of molars in the picture and in my mouth.

Solve the crossword given below.

Across	Down
1. Cream-coloured digestive gland	2. Feeds with the help of pseudopodia
3. Undigested excretory solid residues	6. Total number of molars in one jaw of an adult
4. Organ that mixes saliva with the food	8. Largest gland
5. Point of defecation	9. Watery secretion in the mouth
7. Stored in gall bladder	11. A ruminant
10. Finger-like outgrowth in the small intestine	12. Form of food chewed by ruminants
13. Kind of taste buds
14. Kills bacteria in the stomach