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Chapter Review:

• The saliva breaks down the starch into sugars.
• The canal can be divided into various compartments: (1) the buccal cavity, (2) foodpipe or oesophagus, (3) stomach, (4) small intestine, (5) large intestine ending in the rectum and (6) the anus.
• Liver is the largest gland of body system.
• Salivary gland, liver and pancreas are the main glands of digestive system.
• The digestive juices break down the proteins into simpler substances.
• The liver is a reddish brown gland situated in the upper part of the abdomen on the right side.
• Amoeba is a microscopic single-celled organism found in pond water.
• Amoeba constantly changes its shape and position.
• It pushes out one, or more finger-like projections, called pseudopodia or false feet for movement and capture of food.
• Amino acid is the simplest form of proteins.
• Carbohydrate is the simplest form of sugar or starch.
• Fatty acid (lipid) is the simplest form of fats.
• Food components are mainly absorbed in small intestine.
• Water is absorbed mainly in large intestine.
• Stomach releases gasaric juice and acid. 

2. Nutrition in Animals

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Q1. Fill in the blanks:

(a) The main steps of digestion in humans are __________, __________, __________, _________ and __________.

Ans: ingestion, digestion, absorption, assimilation, egestion

(b) The largest gland in the human body is __________.

Ans: Liver

(c) The stomach releases hydrochloric acid and ___________ juices which act on food.

Ans: gastric

(d) The inner wall of the small intestine has many finger-like outgrowths called _________.

Ans: Villi.

(e) Amoeba digests its food in the ____________ .

Ans : Food vacules

Q2. Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) Digestion of starch starts in the stomach. (T/F)

(b) The tongue helps in mixing food with saliva. (T/F)

(c) The gall bladder temporarily stores bile. (T/F)

(d) The ruminants bring back swallowed grass into their mouth and chewit for some time. (T/F)

Ans:

(a)    F

(b)    T

(c)    T

(d)    T

Q3. Tick ( ) mark the correct answer in each of the following:

(a) Fat is completely digested in the

(i)  stomach  (ii)  mouth    (iii) small intestine   (iv)  large intestine

Ans: (iii) Small intestine

(b) Water from the undigested food is absorbed mainly in the

(i)  stomach  (ii)   foodpipe  (iii)  small intestine  (iv) large intestine

Ans: (iv) Large intestine|

Q4. Match the items of Column I with those given in Column II:

Column I	Column II
Food components	Product(s) of digestion
Carbohydrates	Fatty acids and glycerol
Proteins	Sugar
Fats	Amino acids​

Ans:

Column I	Column II
Food components	Product(s) of digestion
Carbohydrates	Sugar
Proteins	Amino acids
Fats	Fatty acids and glycerol

Q5. – What are villi? What is their location and function?

Ans:– Many small finger-like outgrowths are situated in the inner walls of small intestine, these are called villi.

Functions: The villi increase the surface area for absorption of the digestive food.

Q6. – Where is the bile produced? Which component of the food does it digest?

Ans:– The bile produced in liver.  It is responsible for complete digestion of fats

Q8. Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Ans: cellulose is a type of carbohydrate that can be digested by ruminants but not by humans.

(i) Ruminants have a large sac-like structure between the small intestine and large intestine while human have no so.

(ii) The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

Q9. Why do we get instant energy from glucose?

Ans: Glucose is the simplest form of carbohydrate. It is absorbed very quickly without taking part in any process  and give instant energy to the body.

Q10. Which part of the digestive canal is involved in:

(i) absorption of food ________________.

(ii) chewing of food ________________.

(iii) killing of bacteria ________________.

(iv) complete digestion of food ________________.

(v) formation of faeces ________________.

Ans:

(i) Small Intestine

(ii) Buccal cavity

(iii) Stomach

(iv) Small intestine

(v) Large intestine

Q11. Write one similarity and one difference between the nutrition in amoeba and human beings.

Ans:

Similarity: Both take digestion and use digestive juice to digest food.

Difference: Human need to chew food, whereas in amoeba there is no chewing.

Q12. Match the items of Column I with suitable items in Column II

Column I	Column II
(a) Salivary gland	(i) Bile juice secretion
(b) Stomach	(ii) Storage of undigested food
(c) Liver	(iii) Saliva secretion
(d) Rectum	(iv) Acid release
(e) Small intestine	(v) Digestion is completed
(f) Large intestine	(vi) Absorption of water (vii) Release of faeces

Ans: 

Column I	Column II
(a) Salivary gland	(iii) Saliva secretion
(b) Stomach	(ii) Storage of undigested food (iv) Acid release
(c) Liver	(i) Bile juice secretion
(d) Rectum	(vii) Release of faeces
(e) Small intestine	(v) Digestion is completed
(f) Large intestine	(vi) Absorption of water

                 

Short Answered Questions: 

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Ques:– What is digestion?

Ans:- The breakdown of complex components of food into simpler substances is called digestion.

Ques:- Name the various parts of digestive system.
Ans:- (i) Buccal cavity (ii) food pipe or oesophagus (iii) stomach (iv) small intestine (v) large intestine (vi) rectum (vii) anus

Ques:- By which process amoeba take its food?
Ans:- Endocytosis (engulfing)

Ques:- By the help of which organ does amoeba move?
Ans:- Pseudopodia.

Ques:- What is similar in amoeba and human?
Ans:- Both digest the food.

Ques:- What is absorption?
Ans:- The digested food passes into the blood vessels in the wall of the intestine. This process is called absorption.

Ques:- What is called the process of taking food into the body?
Ans:- Ingestion.

Ques:- Name the substance which breaks down the starch into sugars.
Ans:- Saliva.

Ques:-Where is saliva secreted From?
Ans:- Saliva is secreted from salivary glands situated in the mouth.

Ques:- Name the cavity in which teeth and tongue are situated.
Ans:- Buccal cavity.

Ques:- Write the various types of teeth.
Ans:- (i) Incisor (ii) Canine (iii) Premolar (iv) Molar

Ques:- Which teeth are used for chewing and grinding?
Ans:- Premolar and Molar.

Ques:- Which teeth are used for cutting and biting?
Ans:- Incisor.

Ques:- Which teeth are used for piercing and tearing?
Ans:- Canine.

Ques:- What substance causes tooth decay?
Ans:- acids.

Ques:- Write the cause of diarrhoea.
Ans:- It is caused by infection, food poisoning or indigestion.

Ques:- What is rumen?
Ans:- The grass eating animal quickly swallow the grass and store it in a part of the stomach called rumen.

Ques:- What is cud?
Ans:- When food gets partially digested and is called cud.

Ques:- What are ruminants?
Ans:- In the grass eating animal, cud returns to the mouth in small lumps and the animal chews it. This process is called ruminants.

Ques:- Name the carbohydrate that can’t be digested by the human?
Ans:- Cellulose

Ques:- What substances are secreted by inner lining of stomach?
Ans:- Mucous, hydrochloric acid and digestive juice.

Ques:- Name the movement which occurs during swallowing through oesophagus.
Ans:- Peristalsis movement.

Ques:- Name the largest gland in the body.
Ans:- Liver.

Ques:- Name the substances which are secreted by liver.
Ans:- Bile juice.

Ques:- Name the sac in which the bile juice is stored.
Ans:- Gall Bladder.

Ques:- Name the substance which plays an important role in digestion of fats.
Ans:- Bile juice.

 

Long Answered Questions: 

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Ques:- What is assimilation?
Ans:- The absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances such as the proteins required by the body. This process is called assimilation.

Ques:- What is tooth decay?
Ans:- If we don’t clean our mouth properly after eating it results in growth of harmful bacteria, which break down the sugars present from leftover food and release acids. These acids damage the teeth. This is called tooth decay.

Ques:- Write the functions of saliva.
Ans:- The functions of saliva;
(i) It makes the chewed food soft for swallowing.
(ii) It breaks down the starch into sugars.

Ques:- Write the functions of tongue.
Ans:- The functions of tongue;
(i) We use our tongue for taking.
(ii) It mixes saliva with the food.
(iii) It helps in swallowing food.
(iv) We taste food with our tongue.

Ques:- Name the processes which define the nutrition in human beings.

    Or

Ques:- Name the complex processes by which nutrition is completed.
Ans:- There are five complex processes which define the nutrition in human beings.
(i) ingestion
(ii) digestion
(iii) absorption
(iv) assimilation
(v) egestion

Ques:- What are villi? Write its function.
Ans:- Many small finger-like outgrowths are situated in the inner walls of small intestine, these are called villi.
The villi increase the surface area for absorption of the digestive food.

Ques:- Why can we not digest the cellulose like the cattle?
Ans:- The cattle have a large sac-like structure called caecum between the small intestine and large intestine. The cellulose of the food is digested here by the action of the certain bacteria which are not present in humans.

Ques:- Name the structure in amoeba which helps it to capture the food.
Ans:- Pseudopodia

Ques:- How does amoeba take food?
Ans:- When amoeba senses food it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole. Digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances. Gradually the digested food is absorbed.

Ques:- Draw a label diagram of amoeba.
Ans:-