Question 1:
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)
(ii) and (iii)
(d) (iii) and (iv)
Answer:
(b) The food containing starch (carbohydrate) on reaction.with iodine gives blue-black colour, e.g. Boiled and mashed potato, a slice of bread.
Glucose solution and mustard oil would not give blue-black colour as they are not starch. Mustard oil is fat and glucose is simple unit of carbohydrate.

Question 2:
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
Answer:
(b) Molars and premolars perform similar function of chewing and grinding the food.
The molars are broader and have different ridge structure than molars. The other types of teeth are:

• Inciors, chisel-shaped for biting and cutting food.
• Canines, large and pointed for piercing and tearing food.

Question 3:
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
Answer:
(a) in the human digestive system, parts such as oesophagus, large intestine and rectum do not carry out any digestive functions. Oesophagus carries food from the mouth to the stomach. _
Large intestine absorbs most of the water from undigested food material. Rectum is the last part of the large intestine where undigested food is stored till it is egested out.

Question 4:
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 foodpipe
Answer:
(d) As soon as the food enters the food pipe, the muscles in its walls start alternate contractions and relaxation producing a wave-iike movement called peristaltic. These movements are essential for pushing the food downwards in the alimentary canal.

Question 5:
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
Answer:
(a) The inner lining of stomach secretes mucus, hydrochloric acid and digestive juices.
out of these HCI kills any bacteria that may enter the stomach with food and makes the medium acidic.
Mucus protects the stomach lining from HCI and digestive juices breakdown proteins in food into simpler substances.

Question 6:
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
Answer:
(c) Villi are the finger-like outgrowths of inner surface of human intestine. Their role is to increase the surface area for rapid absorption of digested food.
However, in Amoeba, the finger-like projections are called pseudopoida that helps it to catch food particles and to move.

Question 7:
Read the following statements with reference to the villi of small intestine.
(a) They have very thin walls.
(b) They have a network of thin and small blood vessels close to the surface.
(c) They have small pores through which food can easily pass.
(d) They are finger-like projections.
Identify those statements which enable the villi to absorb digested food.
Choose the correct option.
(a) (i), (ii) and (iv)
(b) (ii), (iii) and (iv)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer:
(a) The inner surface of small intestine has many finger-like outgrowth called villi to help in absorption of food. They have very thin walls to pass digested nutrients through diffusion. The villi are connected to the blood vessels, so the circulating blood can carry these nutrients away.

Question 8:
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
Answer:
(c) The false feet or pseudopodia of Amoeba are finger-like projections that allow movement (keep on appearing and disappearing as it moves) and help to catch food particles from the surroundings.

Question 9:
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
Answer:
(b) The salivary gland present in mouth secretes saliva. It contains the enzyme amylase (ptyalin) that breaks down into simple sugars. Only about 30% starch digestion takes place in the mouth.

Question 10:
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
Answer:
(b) The partially digested food in the rumen (part of stomach) of ruminants (e.g. cow, goat, sheep, etc) is called cud. It is brought back to the mouth in small amounts to be chewed thoroughly.

Question 11:
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) hewing of cud-> swallowing -> mixing with digestive juices -> digestion
(d) swallowing -> chewing and mixing -> partial digestion -> complete digestion
Answer:
(a) The process of nutrition in ruminants occur as: swallowing -> partial digestion (cud) -> cud brought back to mouth -> chewing of cud -> other compartments of stomach -> small intestine -> complete digestion.

Question 12:
Cellulose rich food substances are good sources 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.
Answer:
(a) Human beings do not have cellulose digesting enzymes called cellulase but cellulose.
is still a very important part of human diet. If forms a major part of roughage that is essential for proper digestion.

Very Short Answer Type Questions

Question 13:
Name the parts of the alimentary canal where
(a) water gets absorbed from undigested food
(b) digested food gets absorbed
(c) taste of the food is perceived
(d) bile juice is produced
Answer:
(a) Large intestine (no digestive activity takes place)
(b) Small intestine (numerous villi increase the surface area for absorption)
(c) Tongue (contain taste buds)
(d) Liver (produce bile, that is stored in gall bladder and helps in fats digestion).

Question 14:
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.
Answer:
(a) False, tongue is attached to the floor of the mouth cavity at the back.
(b) False, the large intestine is smaller and wider than the small intestine of the human alimentary canal.
(c) True
(d) True

Question 15:
Choose the odd one out from each group and give reasons.
(a) Liver, salivary gland, starch, gall bladder
(b) Stomach, liver, pancreas, salivary gland
(c) Tongue, absorption, taste, swallow
(d) Oesophagus, small intestine, large intestine, rectum
Answer:
(a) Starch is the odd one. It is a type of carbohydrate. All others are parts of digestive system of human.
(b) Stomach is the odd one. It is a digestive organ. All others are glands.
(c) Absorption is the odd one. It is a digestive process that occurs in small intestine. All others are related to mouth.
(d) Small intestine is the odd one.. It releases intestinal juices and is involved in digestion. All others do not take part in the digestion process.

Question 16:
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. Flow could you do it inspite of being blindfolded?
Answer:
Inspite of being blindfolded, one could identify tastes of different drinks with the help of different types of taste buds present in the tongue.
Taste buds are sensory taste receptors that help to or perception of taste.
There are four kinds of taste buds which detect sweet, salty, sour and bitter taste. These are located in different part of the tongue.

Question 17:
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.
Answer:
(a) mouth; anus
(b) sockets; gums
(c) buccal cavity; small intestine.
(d) liver

Question 18:
Following statements describe the five steps in animal nutrition. Read each statement and give one word for each statement. Write the terms that describe 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.
Answer:
(a) Assimilation
(b) Digestion
(c) Egestion
(d) Ingestion
(e) Absorption

Short Answer Type Questions

Question 19:
Match the animals in Column I with their mode of feeding listed in Column II.

Answer:
The correct matching is as given:
(a) —(iii), (b)—(i), (c)—(iv), (d)—(ii)
(b)Housefly is a sponging insect with sponge-like mouth parts that allow them to eat only liquid foods.
(c) Cockroach has primitive arrangement of mouthparts for biting and chewing.
(d) Mosquito has piercing and sucking mouth parts that pierce food items to enable sucking of internal fluids.
(c) Infants suckle milk, as they have no teeth.

Question 20:
Boojho took some grains of boiled rice in test tube ‘A’ and Paheli took boiled and chewed rice in test tube ‘S’. 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.
Answer:
Iodine solution gives a blue-black colour on reacting with starch. In test tube A, blue-black colour appeared because starch was present. In test tube 6, colour of iodine would not change because it contained chewed rice.
Starch in this case has been broken down into simple sugars by the action of amylase present in saliva. The saliva gets mixed with food on chewing.

Question 21:
‘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?
Answer:
After surgical removal of gall bladder, ‘A’ would face problems in digestion of fatty substances when consumed in bulk.
This is because the bile juice stored in the gall bladder helps in digestion of fats. Removal of gall bladder, thus leads to difficulty in digestion of fatty substances.

Question 22:
Match the organs in Column I with the words listed in Column II.

Answer:
The correct matching is as given:
(a)-(iv),
(b)—(v),
(c)—(i),
(d)-(iii),
(e)-(ii)

Question 23:
Ruminants such as cows and buffaloes swallow their food hurriedly and then sit restfully and chew their food. Can you give reason why?
Answer:
Ruminants such as cows and buffaloes swallow their food hurriedly and store it in a part of the stomach called rumen. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.
Later, this partially digested food (cud) is returned to the buccal cavity of the animals in small lumps and animal chews it sitting restfully to complete the process of digestion. This process is called rumination.
The thoroughly chewed cud is swallowed again to other compartment of stomach and then into small intestine for complete digestion and absorption.

Question 24:
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?
Answer:
Sometimes, when we eat hurriedly or talk or laugh while eating, the flap-like valve (called epiglottis) which closes the passage of windpipe remains open. Therefore, the food may enter into the windpipe and it leads to coughing. Coughing helps to clear the passage.

Long Answer Type Questions

Question 25:
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……………….
(b) Large intestine absorbs…….. and some……… from the undigested food.
(c) Tongue is attached at the………… floor of the mouth cavity and is free at the
(d) Amoeba pushes out around the food and traps it in a food
Answer:
(a) intestinal
(b) water; salts
(c) back; front
(d) pseudopodia; vacuole

Question 26:

Label the given figure as directed below in A to D and give the name of each type of teeth.
(a) The cutting and biting teeth as A
(b) The piercing and tearing teeth as B
(c) The grinding and chewing teeth as C
(d) The grinding teeth present only in adults as
Answer:
The name of each type of teeth are as given:

Question 27:
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 that of other nutrients?
(d) Where is the digestion of fat completed?
(e) Does bile juice digest fat completely?
Answer:
(a) Bile juice is secreted by the liver.
(b) Digestion of fats is difficult as compared to that of other nutrients because of insolubility of fat in water.
(c) Bile juice helps in digestion of fat by breaking down big fat droplets into smaller droplet. This is called emulsification of fats.
(d) Digestion of fat is completed in small intestine.
(e) No, fat is not digested by bile juice. Bile contains bile salts, which helps in its emulsification. This makes the action of pancreatic lipase easier that completes fat digestion.

Question 28:
Label the parts of figure given below 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.
Answer:
The parts of figure and their name are as given:

Question 29:
Open your mouth, look into a mirror and try to count the different types of teeth in your mouth. Compare them with figure of question 30. 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.
Answer:

(a) Yes, the difference has been observed in the number of molars.
(b)The number and type of teeth vary in an adult as compared to a child.
Children have 28 teeth in their mouth.
There are only four molars in each jaw. While, adults have 32 teeth in their mouth which means six molars in each jaw. The third molars, present only in adults are known as wisdom teeth.

Question 30:


Answer: