ICSE Class 9 Biology Solutions Chapter 14 The Respiratory System

Class 9th ICSE Biology Solutions Chapter 14 The Respiratory System

Question 1.
Given below is the definition of respiration with a few blanks to be filled in. Write suitable words in the blanks:
Respiration is a process of releasing ………………………. by breaking down …………………….. for carrying out processes.
Answer:
Respiration is a process of releasing energy by breaking down glucose for carrying out life processes.

Question 2.
Write the overall chemical equation representing the above definition of respiration.
Answer:
C₆H_12O6 + 6O₂ → 6CO₂ + 6H₂O + energy

Question 3.
In what form is the energy liberated in respiration?
Answer:
Energy is liberated in the form of ATP (adenosine triphosphate).

Question 4.
Give two examples of life activities which need energy.
Answer:

1. Production of enzymes.
2. Contraction of muscles for movement.

PROGRESS CHECK

Question 1.
State whether the following statements are true (T) or false (F) :
(i) Strenuous physical exercise may cause fatigue due to accumulation of C02 in the blood. T/F
(ii) NOCO₂ is produced in anaerobic respiration in the human body. T/F
(iii) Breathing and gaseous transport are one and the same thing. T/F
(iv) CO₂ is transported to the lungs by the blood in two forms as bicarbonates and as carbamino-haemoglobin.T/F
(v) Tissue respiration means chemical changes occurring in side the cell. T/F
Answer:
(i) False (ii) True (iii) False (iv) True (v) True.

PROGRESS CHECK

Question 1.
Match the items in Column I with those in Column II.

Column I	Column II
A. Nasal chamber	(i) Production of voice
B. Epiglottis	(ii) C-shaped rings
C. Air-sacs	(iii) Warms air
D. Lungs	(iv) Drives mucus
E. Larynx	(v) Closes wind-pipe during swallowing
F. Trachea	(vi) Network of capillaries
G. Cilia	(vii) Spongy and elastic

Answer:

Column I	Column II
A. Nasal chamber	(iii) Warms air
B. Epiglottis	(v) Closes wind-pipe during swallowing
C. Air-sacs	(vi) Network of capillaries
D. Lungs	(vii) Spongy and elastic
E. Larynx	(i) Production of voice
F. Trachea	(ii) C-shaped rings
G. Cilia	(iv) Drives mucus

Question 2.
How do the following contribute in inspiration during breathing?
(i) Ribs
(ii) Diaphragm
Answer:
(i) Ribs. Ribs are moved inward and outward by the muscles stretched between them, thus enlarging the chest cavity all around.
(ii) Diaphragm. On contraction, it flattens from the dome-shaped outline to an almost horizontal plane and thus contribute to the enlargement of chest cavity lengthwise.

Question 3.
Match the lung capacities in Column I with the quantities given in Column II.

Column I	Column II
A. Residual air	4500 ml.
B. Vital capacity	6000 ml.
C. Total lung capacity	1500 ml.
D. Dead air space	150 ml.

Answer:

Column I	Column II
A. Residual air	1500 ml.
B. Viral capacity	4500 ml.
C. Total lung Çapacity	6000 ml.
D. Dead air space	150 ml.

PROGRESS CHECK

Question 1.
Mention any two points of difference in the quality of inspired and expired air.
Answer:
Points of difference between inspired and expired air :

1. Expired air contains less oxygen as compared to inspired air.
2. Expired air contains some bacteria as compared to inspired air.

Question 2.
Give reasons for :
(i) People climbing to high altitudes may suffer from dizziness and unsteady vision.
(ii) Use of lime water in most experiments on respiration.
(iii) Respiration rate is higher in animals than in plants.
Answer:
As we go higher or to high altitudes, the air has a decrease in the contents of oxygen. Also the pressure of the air is decreased. At about 4500 meters above sea level. One may suffer from air sickness and lack of oxygen leads to dizziness, unsteady vision, loss of hearing and lack of muscular coordination. Sometimes one may feel even complete blackout. All this happens due to decrease in air pressure and decrease in oxygen contents in the air.

(ii) The lime water turns milky when CO₂ is passed through it. Therefore, in most of experiments to check whether the process of respiration is taking place or not, lime water is used.

(iii) The animals consume a lot of energy in doing physical work. They have to more about for obtaining food or run away to escape enemies. They have to look after their young ones or eggs. The birds and mammals need still more energy to keep their body warm. Therefore, the respiratory rate in animals is higher than in plants.

Question 3.
Given alongside is an experiment intended to demonstrate the action of diaphragm, but some thing has gone wrong.
(i) What is the mistake in the diag.? Explain.

Answer:
The experiment set up shows or demonstrates the action of the diaphragm during breathing. The rubber sheet tied round the bottom- edge of the bell-jar represents the diaphragm. When the sheet is pulled downward, the pressure inside the bell jar is lowered and the balloons are expanded by the air, rushing in through the tube at the top.

When the sheet is pushed upward the balloons collapse again due to the air rushing out. This is the mistake in the diagram. The balloons (representing lungs) should collapse when the rubber sheet is pushed upward.

Review Questions

A. Multiple Choice Type

Question 1.
During inspiration, the diaphragm
(a) relaxes,
(b) contracts,
(c) expands,
(d) gets folded
Answer:
(b) contracts

Question 2.
The ultimate end parts of the respiratory system in humans are known as
(a) alveoli,
(b) bronchioles,
(c) tracheoles,
(d) bronchi
Answer:
(a) alveoli

Question 3.
During respiration there is :
(a) gain in dry weight
(b) loss in dry weight
(c) no change in dry weight
(d) increase in the overall weight
Answer:
(b) loss in dry weight

B. Very Short Answer Type

Question 1.
Choose the odd one out in each of the following groups of four items each :
(a) Trachea, Bronchus, Alveolus, Diaphragm
(b) Ethyl alcohol, Carbon dioxide, Starch, Oxygen absence
(c) Diffusion, Respiratory gases, Alveoli, Capillary network
(d) Trachea, Ciliated epithelium, Mucus, Diffusion
(e) Oxyhaemoglobin, Carbaminohaemoglobin, Hypoxia, Carboxyhaemoglobin
(f) Hairy, Moist, Nostril, Vocal cord.
Answer:
(a) Diaphragm
(b) Ethyl alcohol
(c) Diffusion
(d) Diffusion
(e) Hypoxia
(f) Vocal cord.

Question 2.
Name the body structure concerned with the given functional activity :
(a) Prevents food from entering the trachea during swallowing.
(b) Transports oxygen to the body cells.
(c) Helps to increase the volume of the chest cavity lengthwise.
(d) Combines with the oxygen in the lungs.
(e) Protects the lungs from mechanical injuries.
(f) Provides actual diffusion of respiratory gases in the lungs.
Answer:
(a) Epiglottis
(b) Capillaries’
(c) Diaphragm
(d) Bronchioles
(e) Ribs
(f) Alveoli or air sacs.

Question 3.
What is the normal percentage composition of the gases in the inspired and expired air respectively?
Answer:

	Inspired air	Expired air
Oxygen	20-96%	16-4%
Carbon dioxide	0-04%	4-0%
Nitrogen	79-00%	79-6%

Question 4.
Which chemical compound inside a cell can be termed “Currency of Energy”.
Answer:
ATP is called or termed as currency of energy.

Question 5.
Match the items in Column I with the ones most appropriate in column II. Rewrite the matching pairs:

Column I	Column II
(a) Alveoli	(i) where aerobic respiration takes place
(b) Bronchioles	(ii) lined with hair
(c) Nasal chamber	(iii) diffusion of gases
(d) Bronchi	(iv) small air tubes
	(v) An inverted Y shaped tube
	(vi) A common passage for food and air

Answer:

Column I	Column II
(a) Alveoli	(iii) diffusion of gases (1998)
(b) Bronchioles	(iv) small air tubes
(c) Nasal chamber	(ii) lined with hair (1999)
(d) Bronchi	(v) An inverted Y shaped tube

c. Short Answer Type

Question 1.
Given below is an example of a certain structure and its special functional activity “Kidney and excretion.” Fill in the blanks on a similar pattern.
(a) Alveoli and ………….
(b) Mitochondria and…………..
(c) Epiglottis and ………….
(d) Pleura and ………….
(e) Diaphragm and ………….
(f) ‘C’ shaped cartilage rings and ………….
Answer:
(a) Alveoli and gaseous diffusion,
(b) Mitochondria and power houses.
(c) Epiglottis and guard of entrance to trachea.
(d) Pleura and lung covering. ,
(e) Diaphragm and differentiate thoracic cavity and abdominal cavity.
(f) ‘C’ shaped cartilage rings and support.

Question 2.
State one function of each of the following :
(a) Ciliated epithelium lining the respiratory tract
(b,) Mitochondria
(c) Diaphragm
(d) Intercostal muscles
(e) Pleural fluid
Answer:
(a) Ciliated epithelium protective inner lining of respiratory passage. It helps in motion driving any fluid that is on them.

(b) Mitochondria. In mitochondria pyruvic acid is further broken down step by step in a cyclic manner in presence of oxygen.

(c) Diaphragm. Diaphragm contributes to the enlargement of the chest cavity lengthwise.

(d) Intercostal muscles. The muscles help the inward and outward movement of ribs enlarging the chest cavity all around.

(e) Pleural fluid. It provides lubrication for free movement of the expanding and contracting lungs.

Question 3.
Match the items in Column A with those in column B.

A	B
1. Cartilaginous	(a) Epiglottis
2. Large surface area	(b) Diaphragm
3. Breathing movements	(c) Bronchi
4. Voice	(d) Alveoli
5. Complemental air	(e) Larynx
6. Swallowing	(f) Extra inhalation

Answer:

A	B
1. Cartilaginous	(c) Bronchi
2. Large surface area	(d) Alveoli
3. Breathing movements	(b) Diaphragm
4. Voice	(e) Larynx
5. Complemental air	(f) Extra inhalation
6. Swallowing	(a) Epiglottis

Question 4.
Under what conditions would the breathing rate increase?
Answer:
The breathing rate increases after a vigorous physical exercise. Also, accumulation of CO₂ in the blood increases the rate of breathing.

Question 5.
How would you prove that the are you breathe out is warmer?
Answer:
During breathing the air expelled out is always warmer or at the temperature of the body. It can be felt by breathing out the air on own hand. One can feel the warmth of the air expelled out during breathing.

Question 6.
How is the respiratory passage kept free of dust particles?
Answer:
The respiratory tract is lined with cilliated epithelium to remove the mucus and dust particles from the respiratory tract.

Question 7.
What is wrong in the statement “We breathe in oxygen and breathe out carbon dioxide”?
Answer:
Actually, we inhale air which contains much oxygen and a small quantity of CO₂ while giving out or exhaling the/pir contains less quantity of O₂ and more carbon dioxide. Therefore, the statement “we breath in oxygen and breathe out carbon dioxide” is wrong.

D. Long Answer Type

Question 1.
Differentiate between the following pairs on the basis of the aspect given in the brackets.
(a) ‘ Aerobic and anaerobic respiration (end products of the process)
(b) Respiration and photosynthesis (Gas released)
(c) Photosynthesis and respiration (Reactants)
(d) Inspired air and alveolar air (CO₂ content)
(e) Respiration and breathing lungs (organs involved)
(f) Tidal volume and residual volume – (quantity of air)
Answer:
(a) Aerobic respiration:- CO₂ and H₂O is released.
Anaerobic respiration:-Lactic acid and ATP and heat energy released.
(b) Respiration:- CO₂ is released.
Photosynthesis:- O₂ is released.
(c) Photosynthesis :- CO₂ + sunlight + H₂O
Respiration :- Glucose + Oxygen
(d) Inspired air :- 0-04%
Alveolar air:- more CO₂ 4 0%
(e) Respiration :- lungs
Breathing :- lungs
(f) Tidal volume :-1500 ml .
Residual volume:- 500 ml

Question 2.
Give suitable explanations for the following :
(a) Breathing through the nose is said to be healthier than through the mouth.
(b) Why does gaseous exchange continue in the lungs even during expiration?
(c) Why does a person feel breathlessness at higher altitudes?
Answer:
(a) Because, the hair present in the nostrils prevent large particles enter the system.
(b) Expiratipn’ is the result of reverse movements of the ribs and diaphragm. As a consequence of the movements of the ribs and diaphragm, the thorax cavity is diminished and lungs are compressed, forcing the air out into the atmosphere.
(c) At higher altitudes the oxygen content of the air is low. So, a person feels breathlessness at higher altitudes.

Question 3.
With regard to the respiratory system and the process of respiration in man, answer the following questions:
(a) Name the two kinds of muscles that help in breathing.
(b) Briefly describe how the above mentioned muscles help in the inspiration of air.
(c) Give the overall chemical equation to represent the process of respiration in humans.
(d) What is meant by :
1. Residual air and
2. Dead air space
Answer:
(a) (i) Abdominal muscles (ii) Intercostal muscles.
(b) (i) The ribs are moved inward and outward by the intercostal muscles stretched between them and thus, enlarges the chest cavity.
(ii) The diaphragm flattens and presses the organs inside the abdomen and with the abdominal muscles relaxed, the abdominal wall moves outward.
(c) The overall chemical equations of the process of respiration in humans is

(d)
1. Residual air. Some air is always left in the lungs even after forcibly breathing out. This is the left over or residual air.
2.Dead air space. Some tidal air is left in respiratory passage such as trachea and the bronchi where no diffusion of gases can occur. This volume is called dead air pace. This volume is 150 ml.

Question 4.
Starting from the nostrils, trace the path in sequence which the inspired air takes until it reaches the air sacs.
Answer:
Nose → pharynx → larynx → trachea → bronchi.

Question 5.
What are the functions of the following in breathing?
(a) Ribs,
(b) Diaphragm,
(c) Abdominal muscles
Answer:
(a) Ribs. The ribs move inward and outward by the muscles stretched between them, thus enlarging the chest cavity all around.

(b) Diaphragm. On contraction, it falls or flattens from the dome shaped outline to an almost horizontal plane and thus, contributes to the enlargement of the chest cavity lengthwise.

(c) Abdominal muscles. These muscles help in the increase in the size of thoracic cavity by the movement of diaphragm and therefore the inspiration.

E. Structured / Application / Skill Type

Question 1.
Give alongside is a diagrammatic sketch of a kind of part in human lungs.
(i) Name the parts numbered 1-4
(ii) What do the arrows 5 and 6 indicate?

Answer:

(i)
Name of parts 1 to 4 and 5, 6
1. Thin walls of capillary
2. R.B.C. (Red blood corpuscles)
3. Plasma
4. Thin wall of the Alveolus
(ii)
5. CO₂ diffuses out ‘
6. O₂ diffuses in

Question 2.
Given below is an overall chemical reaction of a certain process :
C6H₁₂O6 > lactic acid + 2ATP + heat energy
(a) Name the process.
(b) Is this reaction applicable to animals or to plants or to both animals and plants?
(c) Name one tissue in which this reaction may occur.
Answer:
(a) Anaerobic respiration.
(b) This reaction is applicable to animals only.
(c) This reaction may occur in muscular tissues (skeletal).

Question 3.
Given below are chemical reactions (1 to 5) involving glucose and five other chemical products (A-E).

(a) Write the reaction number of the following ;
(i) Anaerobic respiration in plants ………………
(ii)End-products in aerobic respiration ………………
(iii)Reaction occurring in liver………………
(iv) Anaerobic respiration in animals…
(v) Storage in liver………………
(b) Which reactions (1-5) in the above correspond to the following (write the corresponding number of reaction next to them).
(i) Aerobic respiration ………………
(ii) Change taking place in the liver ………………
(iii) Anaerobic respiration in yeast ………………
(iv) Change taking place in a plant storage organ, e.g., potato ………………
(v) Anaerobic respiration in animals ………………
Answer:
(a)
(i) Anaerobic respiration in plants [5]
(ii) End product in aerobic respiration [4]
(iii) Reaction occurring in liver [2]
(iv) Anaerobic respiration in animals [1]
(v) Storage in liver [3]
(b)
(i) Aerobic respiration [4]
(ii) Change taking place in the liver [3]
(iii) Anaerobic respiration in yeast.[5]
(iv) Change taking place in a plant storage organ, e.g., potato [2]
(v) Anaerobic respiration in animals [1]

Question 4.
The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.
The following diagram shows a group of the lung volumes and capacities. .
Study the diagram carefully and explain briefly the following:
(a) Tidal volume (TV)
(b) Inspiratory reserve volume (IRV)

(c) Expiratory reserve volume (ERV)
(d) Vital capacity (VC)
(e) Residual volume (RV)
Answer:
(a) Tidal volume (TV) ;
The air breathed in and out in a normal quite breathing is 500 ml.

(b) Inspiratory reserve volume (IRV) ‘
Air that can be drawn in forcibly over and above the tidal * air which is also called complemental air is 3000 ml.

(c) Expiratory reserve volume (ERV)
Air that can be forcibly expelled out after an ordinary ” expiration which is also called supplemental air is 1000 ml.

(d) Vital capacity (VC)
The volume of the air that can be taken in and expelled out by maximum inspiration and expiration is called vital capacity. It is 4500 ml.

(e) Residual volume (RV)
Some air is always left in the lungs even after forcibly breathing out. This is called residual volume. It is 1500 ml.

Three Common Experiences Related To Breathing

Hiccups -“Jerky incomplete inspiration” (nothing to do with some one remembering you).
Sneezing – “Forceful sudden expiration” (A protective reflex). Snoring – “Vibration of the soft palate during breathing while sleeping.”
All these are related to Respiratory System , (Name the organ-system)

ICSE Class 9 Biology Solutions