Digestive System Concise ICSE Class-9 Biology Selina Publishers

Revised Biology Chapter-11 Digestive System Solutions

Digestive System Concise ICSE Class-9 Biology Selina Publishers Chapter-11 . We Provide Solutions of Progress Check , MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type Questions and Structured / Applications / Skill Type Questions of Exercise-11 Respiration in Plants. Visit official Website CISCE  for detail information about ICSE Board Class-9.

Digestive System Concise ICSE Class-9 Biology Selina Publishers

.–: Select Topics :–

1_Progress Check (page-107),

2_Progress Check (page-109),

3_Progress Check (page-112),

4_Progress Check (page-113),

5_Progress Check( Page-114)

A.MULTIPLE CHOICE TYPE,

B.VERY SHORT ANSWER TYPE,

C.SHORT ANSWER TYPE,

D.LONG ANSWER TYPE

E. Structured /Application/Skill Type

Note :-  Before Viewing Concise Solutions of Chapter-11 Digestive System. Read the whole chapter carefully with figure. Focus on The structure of a tooth , different types of teeth. Function of different types of teeth .

Dental formula for adult, their function (including enzymes and their functions in digestion, absorption  and assimilation of digested food). brief idea of peristalsis.


Progress Check (page-107), Chapter-11 Digestive System Concise Biology Solutions  

Question 1 

Given……………pharynx.

Answer 1

 Correct sequence is-Pharynx, Oesophagous, Stomach,Small intestine, Large intestine

Question 2

Name the following.

(i)…….

(ii)…….

(iii)…….

Answer 2

(i)Duodenum ,jejunum,Ilium

(ii)Caecum, Colon ,Rectum

(iii)Parotid, Sub mandibular, Sublingual Gland,

Question 3

Give ….jaw.

(i)…….

(ii)…….

(iii)…….

(iv)…….

Answer 3

(i)…….Molar

(ii)…….Canine

(iii)…….Incisor

(iv)…….Milkn Teeth

Question 4

Name the following Part of Tooth

(i)…….

(ii)…….

(iii)…….

(iv)…..

(v)…….

Answer 4

(i)…….Crown

(ii)…….Enamel

(iii)……Pulp

(iv)…..Cement 

(v)…….Neck


Progress Check (page-109), Selina Solutions of Chapter-11 Digestive System 

 Question

Mention………false(F):

(i)…….

(ii)…….

(iii)…….

(iv)…..

(v)…….

(vi)……

(vii)……….

Answer

(i)….True

(ii)…..False

(iii)……True

(iv)…..True

(v)…..False

(vi)……False

(vii)…..True


Chapter-11 Digestive System Progress Check (page-112) Concise Biology Solutions  

Question 1

Mention if….false(F)

(i)….

(ii)….

(iii)….

(iv)…

(v)….

(vi)…..

Answer 1

(i)….True

(ii)….False ( intestine is narrow for slow movement)

(iii)….True

(iv)…True

(v)….True

(vi)…..True

Question 2

Name the enzyme which digest:

(i)…….

(ii)…….

(iii)…….

(iv)…..

Answer 2

(i)…Amylase/Ptylin

(ii)…..Lipase

(iii)…..Trypsin

(iv)…..Sucrose

Question 3

What are the end product of digestion of

(i)…….

(ii)…….

(iii)…….

(iv)…..

Answer 3

(i)….Peptide, Amino Acid

(ii)…..Fatty acid, Glycerol

(iii)…..Maltose

(iv)…..Glucose or Fructose


Progress Check (page-113), Selina Publishers Solutions Chapter-11 Digestive System

Question

Fill in the blnaks

(i)…….

(ii)…….

(iii)…….

(iv)…..

Answer

(i)…Glycogen

(ii)…RBCs

(iii)…..Liver,……Amino Acid.

(iv)…..38


Progress Check( Page-114) Digestive System Solutions Chapter-11 for Selina Biology

Question

(i)

(ii)

(iii)

(iv)

Answer

(i) Protien

(ii)  Starch

(iii) Flucose

(iv) Mineral Substances


Review Question 

 A.Multiple Choice Questions: Chapter:- 11 Digestive System Solutions for ICSE Class 9th Concise Biology 

Question 1

Pylorus is an opening from

(i) oseophagus into stomach

(ii) mouth cavity into stomach

(iii) stomach into intestine

(iv) intestine into rectum

Answer 1

(iii) stomach into intestine

Question 2

Gastric juice contains

(i) HCl and pepsin

(ii) pepsin and trypsin

(iii) trypsin and HCl

(iv) amylopsin and pepsin

Answer 2

(i) HCl and pepsin

Question 3

The water from the digested food is mainly absorbed by

(i) stomach

(ii) duodenum

(iii) colon

(iv) rectum

Answer 3

(iii) colon

Question 4

Which one of the following pairs of types of teeth perform one common function as stated against it?

(i) Incisors, canines – Holding

(ii) Canines, premolars – Biting

(iii) Premolars, molars – Grinding

(iv) Molars, incisors – Tearing

Answer 4

(iii) Premolars, molars – Grinding


B. VERY SHORT ANSWER TYPE Chapter:- 11 Digestive System Selina Solutions 

Question 1

What is the dental formula of a normal human adult?

Answer 1

The dental formula of a normal human adult is:

Human adult = = 32 (Permanent teeth + Wisdom teeth)

Question 2

Mention two reflexes which occur when a person chews and swallows food.

Answer 2

The two reflexes which occur when a person chews and swallows food are:

Reflex when a person chews – Secretion of saliva

Reflex when a person swallows – Tongue presses upward and back against the roof (palate)

Question 3

Consider the following two statements A and B and select the right option from (i)-(iv) about their correctness.

Small intestine is shorter than large intestine.

Small intestine is wider than large intestine.

Options :

(i)Both the statements are correct

(ii) Both the statements are wrong

(iii) Statement A is correct, B is wrong

(iv) Statement B is correct, A is wrong

Answer 3

(ii) Both the statements are wrong. Small intestine is longer (7 metres) than large intestine (1.5 metres). Also, large intestine is so called because of its width which is larger than that of small intestine.


C. SHORT ANSWER TYPE Chapter:- 11 Digestive System Solutions for Selina Publishers

Question 1

What is digestion? Why do only animals require a digestive system?

Answer 1

Digestion is the process of breaking down complex food materials into simpler substances by the action of enzymes.

Need for a digestive system:

(i) Large complex molecules like carbohydrates, proteins and lipids need to be broken down to simpler molecules. These simpler molecules can then be absorbed and utilized by the body.

(ii) The breaking down of complex food molecules into their simpler form is possible only through the process of digestion.

(iii) During digestion, large complex macromolecules present in food are converted into small simpler molecules, which can be simplified in different compartments of digestive system only.

Question 2

What are the end products of the digestion of: starch, proteins and fats respectively?

Answer 2

SUBSTRATE END

PRODUCTS

Starch Maltose
Proteins Small

peptides

and

amino

acids

Fats Fatty

acids

and

glycerol

 

Question 3

Why is there no enzyme to digest vitamins?

Answer 3

Vitamins are used in their original form by the cells. They do not require digestion. So They are either water soluble or fat soluble, hence no enzyme is required to digest vitamins. It is  absorbed directly from the digestive tract, transported by blood to the cells, and the cells absorb and use them whenever they need. Besides, vitamins themselves act as catalysts or enzymes in essential chemical reactions that take place in the body.

Question 4

How is thorough chewing of food helpful in digestion?

Answer 4

It is very important to chew our food thoroughly as chewing of food helps to break down complex food materials into simpler substances. The act of chewing stimulates the salivary glands to release saliva. The saliva helps to moisten the food and form bolus, which can be swallowed easily. Saliva also contains special enzymes that help to break down carbohydrates.

Question 5

What is the function of rectum?

Answer 5

Rectum acts as a temporary storage site for undigested food. It has voluntary smooth muscles that remove the faeces out of the body through the anus.

Question 6

What is roughage? Give two examples.

Answer 6

Roughage is a dietary fibre that largely consists of cellulose. It cannot be digested by our body as our body does not contain cellulose-digesting enzymes.

Examples of roughage:
  1. Fruits
  2. Green leafy vegetables

Question 7

Mention two ways in which the ileum of the mammal is adapted for the absorption of digested food.

Answer 7

Adaptations of ileum for the absorption of digested food:

(1) Very long to provide more surface area for absorption

(2) Presence of large number of villi to further increase the surface area

Question 8

The stomach secretes gastric juice, which contains hydrochloric acid. What is its function?

Answer 8

Functions of hydrochloric acid:

(1) It gets mixed with food and kills the bacteria present in food.

(2) It activates pepsin to act on proteins.


D. LONG ANSWER TYPE Chapter:- 11 Digestive System Solutions for ICSE Class 9th Concise Biology 

Question 1

Prepare a possible vegetarian menu for your dinner which would provide all the necessary nutrients.

Answer 1

Vegetarian menu for dinner:

 

Foodstuffs Weight (gm/ml)
Cereals 320
Pulses 70
Green leafy vegetables 100
Root vegetables 75
Fruits 75
Milk 600
Fat and oil 30
Brown sugar and jaggery 30

 

Question 2

What are the main characteristics of an enzyme ?

Answer 2

Enzymes are biological  catalysts. They speed up reaction although they are not changed in the  reaction . Enzymes are proteins , and therefore are folded chains of amino acids with a specific shape.

Question 3

Why is the small intestine the most important organ of the digestive system?

Answer 3

The small intestine is the most important organ of the digestive system as it serves both, for digestion and absorption. It receives two digestive juices; the bile and the pancreatic juice in the duodenum. These two juices virtually complete the digestion of starch, proteins, carbohydrates, etc. After the breakdown of food, the small intestine absorbs simple substances such as glucose, amino acids, etc.

Question 4

How is the liver an important organ in our body?

Answer 4

Liver is an important organ in our body as it serves the following functions:

Production of bile

Control of blood sugar levels

Control of amino acid levels

Synthesis of foetal red blood cells

Produce fibrinogen and heparin

Regulate blood volume

Destroy dead red blood cells

Store vitamin and minerals

Excrete toxic and metallic poisons

Produce heat

Detoxification

Question 5

Define the following terms :

(a) Peristalsis

(b) Omnivore

(c) Pylorus

(d) Kilocalorie

(e) Basal metabolic rate

Answer 5

(a) Peristalsis:

Peristalsis is the rhythmic contraction and relaxation of the muscles of the alimentary canal that pushes the food along the gut.

(b) Omnivore:

 Omnivores are organisms that consume both plants and animals.

(c) Pylorus:

 Pylorus is the passage at the lower end of the stomach that opens into the duodenum.

(d) Kilocalorie:

 A kilocalorie is a unit of energy. It is the energy required to raise the temperature of 1 kg of water by 1 Celsius.

(e) Basal metabolic rate: 

Basal metabolic rate refers to the minimum amount of energy in the form of calories that our body requires to complete its normal functions.

Question 6

List the enzymes and their action on food in the stomach and intestine.

Answer 6

REGION ENZYME ACTION

ON

FOOD

Stomach Pepsin Acts on proteins

and

converts

it into polypeptides

Small intestine
Duodenum Amylopectin Acts on

starch

and

converts

it into

maltose

Trypsin Acts on remaining proteins, proteoses

and

peptones

to produce peptides

and

amino

acids

Ileum Erepsin Acts on proteins

and polypeptides and

converts

them into small

peptides

and

amino

acids

Sucrase Acts on sucrose

and

converts

it into

glucose

and

fructose

Lactase Acts on lactose

and

converts

it into

glucose

and

galactose

 

Question 7

Give any four reasons why water is necessary in our body.

Answer 7

Importance of water in our body:
  1. Water is the major component of blood, which carries nutrients and oxygen, to and from all the cells.
  2. It is the major component of saliva and mucous, which lubricate the membranes that line our digestive system beginning with the mouth.
  3. It helps in regulating the temperature of the body.
  4. Water is very essential for digestion as well as absorption of food.

Question 8

You have been supplied with a sample of food. How will you perform tests for the presence of starch and proteins on it?

Answer 8

Test for starch:
  1. Take the food item to be tested. Put it into a test-tube containing water and boil to make a solution.
  2. Cool the solution and add 2-3 drops of dilute iodine solution to it.
  3. Blue-black colour of the solution indicates the presence of starch in the food item.
Test for proteins:
  1. Take the food item to be tested in a test tube.
  2. Add few drops of dilute nitric acid to it.
  3. Heat the test-tube gently.
  4. Rinse off the acid with water and add few drops of ammonium hydroxide to it.
  5. Colour change from colourless to yellow and then from yellow to orange red indicates the presence of protein in the food item.

E. STRUCTURED/APPLICATION/SKILL TYPE Chapter- 11 Digestive System Solutions for ICSE Class 9th Concise Biology 

Question 1

Draw a labelled diagram to show the internal structure of a mammalian tooth with two roots.

Answer 1

 internal structure of tooth

    Internal structure of a mammlian tooth

Question 2

Try to swallow the saliva in your mouth, and feel with your hand your neck. What happens in the neck?

Answer 2

While swallowing saliva in the mouth, the larynx is pulled upwards to bring it close to the back of the tongue, when a flap called epiglottis closes its opening. Then, it goes towards the oesophagus.

Question 3

Complete the following table by filling in the blanks 1 to 8.

Organ Enzyme Food

acted

upon

Find

product

1 Pepsin 2 3
Mouth 4 5 Di

saccharide

6 7 Maltose 8

 

Answer 3

Organ Enzyme Food

acted

upon

Find

product

Stomach Pepsin Proteins Poly

peptide

Mouth Amylase Starch Di

saccharide

Ileum Maltase Maltose Glucose

 

Question 4

Study the diagram given below and then answer the questions that follow:

enemel

(a) Name the parts labelled 1, 2, 3, 4, 5 and 6.

(b) Identify the tooth and give a reason to support your answer.

(c) Describe the structure of the part labelled ‘3’.

(d) Give the total number of the type of tooth mentioned in ‘1’ above, in the mouth of an adult and state its function.

Answer 4

(a)

1 → Enamel

2 → Dentine

3 → Pulp

4 → Gum

5 → Crown

6 → Cement

(b)

 The tooth shown in the diagram has only one root, so it is an incisor or canine which is used for biting and piercing.

(c)

 The part labelled ‘3’ (pulp) is a soft connective tissue present in the pulp cavity of the tooth. It consists of blood capillaries, lymph vessels and nerve fibres. These extend from the crown of the tooth and open through the pulp cavity at the base of the root.

(d)

 Type of teeth in the mouth of an adult:

  1. Incisors (8) → Used for biting and cutting
  2. Canines (4) → Used for holding and tearing of food
  3. Premolars (8) → Used for grinding and crushing of food
  4. Molars (12)→ Used for grinding and crushing of food

Question 5

Study the following dental formula and then answer the questions that follow:

………….

(a) State the total number of teeth present in the dentition.

(b) Is the dentition that of a carnivore or herbivore? Give a reason to support your answer.

(c) Name an animal possessing such a dentition.

(d) Give the dental formula of an adult human being.

Answer 5

(a) A total of 20 teeth are present in the given dentition.

(b) The given dentition is that of a herbivore because there are no canines present in the dentition. Canines are required by carnivores as they help in holding and tearing of food. The teeth of herbivores are used for cutting, gnawing, and biting, while the teeth of carnivores are sharper and more suited for catching, killing and tearing the prey.

(c) The given dentition is likely to be present in any herbivore such as deer.

(d) Dental formula of an adult human being is.

2,1,2,3

2,1,2,3

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