Selina solutions concise biology class 9 icse Solutions for Chapter 11 digestive system

Exercises in Chapter 11 digestive system Grade 9

Exercise

Questions in Exercise

Mention if the following statements are true (T) or false (F).

(i) The flexor and extensor muscles of the arm are antagonistic muscles T/F

(ii) Muscles can contract as well as elongate T/F

(iii) Muscles are attached to bones by ligaments T/F

(iv) Cardiac muscle is a voluntary muscle T/F

(v) Bending of arm on elbow is an example of first order of lever mechanism. T/F

Name the following parts of a tooth: (i) Part exposed above the gum. (ii) The hard substance making the covering of the tooth. (iii) The soft connective tissue contained in the central space of the tooth. (iv) Bone-like structure fixing the root in position. (v) Slight constriction between the root and the crown.

Mention if the following statements are true (T) or false (F):

(i) Saliva moistens and lubricates food

(ii) Saliva contains a protein-digesting enzyme

(iii) Saliva tends to destroy germs in the mouth

(iv) Peristalsis occurs through all regions of the gut

(v) The food in stomach stays for about 10 hours

(vi) Gastric juice is alkaline

(vii) Gastric juice contains pepsinogen

Mention if the following statements are true(T) or false(F)

(i) Intestinal villi have a lymph vessel called lacteal.

(ii) Intestine is narrow for fast movement of food.

(iii) Large intestine secretes no enzymes

(iv) Bile neutralizes the acid content of the food received from the stomach

(v) Pancreatic juice has enzymes to digest all the major components of food.

(vi) The anus is surrounded by circular muscles

Name the enzyme which digests: (i) Starch in the mouth (ii) Fats in the ileum (iii) Protein in the duodenum (iv) Sucrose in the ileum

Fill in the blanks: (i) Liver stores glucose as ___________ (ii) Liver produces ___________ only in embryo (iii) Urea is produced in ___________ by the de-amination of extra ___________ (iv) For testing the action of saliva on starch the material has to be kept at a temperature of about ___________ °C.

Mention the constituents of food if the end result of the test shows:

(i) White to yellow and yellow to orange colour (after adding ammonium hydroxide).

(ii) Turning blue-black after adding iodine solution

(iii) Blue green to deep red with appearance of a precipitate when added to Fehling solution

(iv) Ash that does not burn after continued heating

Pylorous is an opening from

(a) Oesophagus into stomach

(b) Mouth cavity into esophagus

(d) Intestine into rectum

Gastric juice contains

(a) HCl and pepsin

(b) Pepsin and trypsin

(d) Amylopsin and pepsin

The water from the digested food is mainly absorbed by

(a) Stomach

(b) Duodenum

(d) Rectum

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

(a) Incisors, canines - Holding

(b) Canines, premolars - Tearing

(d) Molars, incisors - Tearing

What are antagonistic muscles? Give one example.

What is the dental formula of a normal human adult?

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

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

A. Small intestine is shorter than large intestine.

B. 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.

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

What are the end-products of the digestion of:

Starch, proteins and fats respectively?

Why is there no enzyme to digest vitamins?

How is thorough chewing of food helpful in digestion?

What is the function of rectum?

What is roughage? Give two examples.

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

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

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

What are the main characteristics of an enzyme?

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

How is the liver an important organ in our body?

Define the following terms: (a) Peristalsis (b) Omnivore (c) Pylorus (d) Kilocalorie (e) Assimilation

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

Give any four reasons why water is necessary in our body

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

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

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

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

organ	enzyme	food acted upon	final product
1	pepsin	2	3
mouth	4	5	disaccharide
6	7	maltose	8

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

(a) Name the parts labeled 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 labeled ‘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.

Study the following dental formula and then answer the questions that follow: i- c- pm- m (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.