STD 9 Biology: Chapter 04 Breathing for Energy - Questions and Answers

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Class 9 Biology Questions and Answers
Chapter 4: Breathing for Energy 
* What is the purpose of the distribution of iron tablets in schools as part of the WIFS programme?
Ans.
Haemoglobin is necessary for the transport of Oxygen. The main constituent of haemoglobin is iron. If the amount of haemoglobin in the blood decreases it will lead to a disease called anaemia. Iron tablets are distributed in schools as part WIFS programme is to avoid this.


* Respiration?        
Respiration is the process of releasing energy from food nutrients.
• Aerobic respiration
(Releasing energy with the help of oxygen)
• Anaerobic respiration
(Releasing energy without oxygen)

* Respiration in man includes
*  Breathing (inspiration & expiration) 
*  Exchange of respiratory gases     
*  Cellular respiration.

* Human Respiratory System (parts of the respiratory tract)


Each bronchiole enters a set of alveoli (air sacs), which are surrounded by a number of blood capillaries. The alveoli increase the respiratory surface area of the lungs and thus increase the efficiency of the exchange of gases.

• Pleura?
The double-layered outer membrane of the lungs with pleural fluid, which prevents friction.
• The pathway of air through the respiratory tract (from nostrils to the alveoli):

* A. Breathing  (Process of Inspiration and Expiration)
Occur by the combined working of the diaphragm (a flat muscular structure between the thoracic and abdominal cavities) and intercostal muscles (muscles seen in between the ribs).

Oxygen is more in inhaled air. CO₂  and water vapour are more in exhaled air.

* B. Exchange of gases
From the alveoli of lungs, oxygen diffuses to the red blood corpuscles of the surrounding blood capillaries. The iron of haemoglobin, seen in the RBCs, absorb oxygen to form a less stable compound 'oxyhaemoglobin' and is transported. Oxygen diffuses into the tissue fluid and then into the cells. 
 CO₂ diffuses from blood to the alveoli, where its concentration is low.

• How far is the structure of red blood cell suitable for carrying oxygen?
Red blood corpuscles can carry more oxygen in its haemoglobin molecules, because of their disc shape and absence of nucleus or other cell organelles within them. Oxygen has an affinity to combine with haemoglobin, due to the iron in it. Our blood contains 45 to 60 lakh RBCs per each ml.

• How many oxygen molecules can be carried by one haemoglobin molecule?
- Four.

• Why is it advisable to include iron contained food items like leafy vegetables in our diet? (What is the importance of taking iron tablets ?)
Iron in the haemoglobin of RBCs carries oxygen molecules through our blood. Iron contained food helps to prevent anaemia.

• Define anaemia.
Anaemia is a condition in which the amount of haemoglobin in the blood decreases. (The average amount of haemoglobin  in a healthy man is 15gm/100ml and that of a woman is 13gm/100ml of blood)

• The pathway of oxygen from alveoli to the cells:


* C. Cellular Respiration?  
The process of energy production in cells. It has two stages.

• How is CO₂  eliminated?
70% CO₂ is eliminated as bicarbonate by dissolving in the water of plasma and the RBCs, 23%  as carbaminohaemoglobin and 7% as dissolved in blood plasma water.

* Comparison between Photosynthesis and Aerobic respiration
• How does the respiratory system help to maintain the homeostasis (internal equilibrium of the body)?
Through eliminating excess CO₂ and a trace of water vapour.

• How excess CO₂  is harmful to our body?
CO₂ may combine with water to form carbonic acid, which in turn increases acidity in blood and tissue fluid. To avoid these lungs eliminate excess CO₂. 

* Anaerobic Respiration (Fermentation)
Certain bacteria and yeast produce energy through anaerobic respiration (also known as fermentation) Illustration of lactic acid fermentation and alcohol fermentation is given below: 


• Reason for muscle fatigue after strenuous work or exercise?
During strenuous work or exercise, oxygen may cease and anaerobic respiration occurs for energy production resulting in the formation of lactic acid in the muscle cells.

• The things that can cause damage to our respiratory system?
In taking of smoke, dust, fog, germs and chemicals, the habit of smoking etc.

* Respiratory disorders caused by smoking
• Lung cancer due to the carcinogens contained in tobacco.
• Emphysema (rupture of alveoli when elasticity is lost) due to the toxic substances of tobacco.
• Bronchitis (mucus deposition and swelling of lungs) due to the proliferation of germs by the tar or carbon monoxide in tobacco.

• What do you mean by the terms, tidal volume and vital capacity?
- The volume of air breathed in and out during normal breathing is the tidal volume. (it is about 500 ml). The maximum volume of air that we can breathe in and out is called the vital capacity of our lungs. (it is about 3 litres in females and 4.5 litres in males) 

• Experimental set up for measuring the vital capacity of lungs.
- Take two jars with lids. Fill water half the level of the first jar. Close the lid and attach a U shaped tube and connect it with the empty second jar. Attach a tube to the first jar lid in order to blow air. Forefully blow air into the jar. The water that is exppelled from the first jar and filled in the second jar will be equal to the vital capacity.

• The organ or mode and the process of respiration in Amoeba, Cockroach and Fish.
Amoeba  - The cell membrane, through which oxygen diffuses from water.
Cockroach - Trachea, (a network of tubules), through which oxygen diffuses to cells from the atmosphere.
Fish - Gill is the organ through which oxygen diffuse to blood, from water.

* Mechanisms of gas exchange in plants
• through the stomata seen on leaves and green tender stems.
• through lenticels (small pores on the surface of stem and roots)

* Observe the following illustration and answer the questions
(a) How does the difference in concentration of A in alveoli and blood capillaries during inspiration help in this process?
(b) How the structure of Red blood cells is suitable for the formation of C?
Ans. 
(a)During inspiration, the concentration of oxygen is high in the alveoli. But, in the blood capillaries, the concentration of oxygen is low. As a result of this, oxygen from the alveoli diffuses into the capillaries.
(b)  Haemoglobin which has a great affinity to oxygen is abundantly present
* If the carbon dioxide produced as a result of cellular respiration is not removed, it will affect homeostasis - What is your response to this statement?
Ans. Carbon dioxide combines with water present inside and out of the cell to form carbonic acid. The increase in the level of carbonic acid increases the acidity in the body. This changes the internal environment.

* Compare the process of respiration in Cockroach and fishes
Ans.
Cockroach - Directly with tissues using trachea
Fishes - directly to blood using gills

* Find the word pair relationship and fill in the blanks. Write the relationship between words
Cockroach: Trachea
Amoeba:…………..
Ans.
Cell membrane, Respiratory Organ / Mode of Respiration in organisms

* Observe the picture and answer the following questions.

(a)What is the aim of this experiment?
(b)What does the increase in the level of water in the second jar indicate? How is this beneficial to the body?
Ans.
(a)Measurement of vital capacity.
(b)The volume of water in the second jar will be proportional to vital capacity. When vital capacity increases, the level of oxygen dissolving in blood and thus energy production increases.

* "Young man was saved by a lifeguard from drowning while bathing in the sea." - News
What first aid should be given to a victim in such situations?
Ans.
- The person must be rescued immediately from the water.
- Expel water which has entered the body.
- Provide artificial respiration.

* Find the word pair relationship and fill in the blanks.
Heart: Pericardium
Lungs:………….
Ans. Pleura

* Analyze the following statements and choose the correct answer.
a. Bronchioles are supported by cartilaginous rings.
b. The exchange of respiratory gases takes place in pleura.
c. Nasal cavity connects the nostrils with the pharynx.
d. Diaphragm separates the thoracic and abdominal cavities.
A. a, c is right
B. c,d are right
C. a is right
D. b,d is right
Ans. B) c,d are right

* “Like how the pericardium is to heart, so is the pleura to lung”-This is the opinion of a student in a discussion on the respiratory system. Is there a basis for this comparison? Justify.
Ans.
- Yes
- Both are double-layered membranes.
- Both are protective layers.
- In both, the fluid present in between two layers reduce the friction

* How far is the peculiarity of alveoli suitable for their function?
Ans.
- Alveolar membranes are thin and elastic.
- Alveoli are surrounded by numerous blood capillaries.
- The wall is made up of a single layer of cells.
- The inner wall of the alveoli is always moist.
- Alveoli increase the respiratory surface area in the lungs

* Write the reason for the diffusion of blood from the alveoli to the blood capillaries.
a. Less concentration of oxygen in the blood.
b. Decreased thickness of the walls of alveoli and blood capillaries.
c. Increased concentration of oxygen in the alveoli.
d. All of the above.
Ans. (d) All the above

* Does the haemoglobin has any role in the transport of oxygen and carbon dioxide? How?
Ans.
- Yes
- Oxygen is transported in the form of oxyhaemoglobin and Carbon dioxide is transported in the form of Carbamino haemoglobin.

* Compete for the following table suitably.

Inspiration

Process

Expiration

.............

Raises

.............

.............

............

Diaphragm

Ribs

Volume of thoracic cavity

Pressure in the thoracic cavity.

Air

............

...........

...........

...........

Expelled out

Ans. 

Inspiration

Process

Expiration

Contracts

Raises

Increases

Decreases

Enters in

Diaphragm

Ribs

Volume of thoracic cavity

Pressure in the thoracic cavity

Air

Relaxes

Lowers

Decreases

Increases

Expelled out



* How do the contraction and relaxation of diaphragm and ribs help in inspiration and expiration? Write your inferences?
Ans.
- Diaphragm contracts, ribs raise due to the contraction of the intercostal muscles, Volume of the thoracic cavity increases-inspiration takes place
- Diaphragm relaxes, ribs lower due to the relaxation of intercostal muscles, the volume of the thoracic cavity decreases-expiration takes place

* Copy the diagram.

* Complete the following illustration
Ans.
(a)Blood capillary
(b)Carbon dioxide

* The vital capacity of three men A, B and C are given in the graph below.
Analyze the graph and answer the questions.
(a) Whose vital capacity is in a healthy condition?
(b)Give two suggestions that will increase your vital capacity?
Ans.
a)B
b) Do proper exercise, avoid smoking

* Find the word pair relationship and fill in the blanks.
Stem: Lenticel
Leaves:……………
Ans. Stomata

* Complete the given flowchart using appropriate sentences.
(a)Red blood cells-Oxygen combines with haemoglobin to form Oxyhaemoglobin
(b)Blood capillaries in tissues-Haemoglobin releases oxygen and becomes free

* “It is necessary to include food items like leafy vegetables with iron content in our diet for the proper health of respiratory system” Do you agree with the above statement? Justify
Ans.
Yes, The main constituent for the synthesis of haemoglobin is iron molecules. Haemoglobin is necessary for the transport of oxygen.

* Complete the following table on the basis of indicators

* Find the word pair relationship and fill in the blanks.
(a) Glycolysis: Cytoplasm
Krebs cycle:……………
(b)Glycolysis: 2 ATP
Krebs cycle:……………
Ans.
(a)Mitochondria
(b)28 ATP

* Find the word pair relationship and fill in the blanks
Vital capacity: 4.5 litre
Tidal Volume: ………..
Ans. ½ litre

* Which one of the following is not related to inspiration?
(a)Diaphragm relaxes.
(b)Volume of the thoracic cavity increases.
(c)Pressure in the thoracic cavity decreases.
(d)Ribs raises.
Ans. (a)Diaphragm relaxes.

* Complete the following chemical equation related to respiration
Ans.
(a)Glucose/Oxygen
(b)Oxygen/Glucose
(c)Carbon dioxide/Water
(d)Water/Carbon dioxide

* Find the word pair relationship and fill in the blanks
Oxygen + Haemoglobin: Oxyhaemoglobin
Carbon dioxide + Haemoglobin:…………………….
Ans. Carbaminohaemoglobin
* Find the word pair relationship and fill in the blanks
Bacteria: ……………...
Yeast: Alcohol
Ans. Lactic acid

* Observe the two activities given below.
Activity 1
Glucose + Oxygen ----------> Carbon Dioxide + Water + Energy
Activity 2
Carbon dioxide + water ------------> Glucose + Oxygen
a) Identify the activity which occurs in both plants and animals.
b) Which activity takes place only in plants?
Ans.
(a) Activity 1
(b )Activity 2

* Find the word pair relationship and fill in the blanks
Cellular respiration:30 ATP
Fermentation:-------------
Ans. 2 ATP

* Find out the odd one and write the common feature of others
(a)Emphysema,Bronchitis,Uremia,Lung cancer
(b)bronchus,Alveoli,Pleura,Pericardium
Ans.
(a) Uremia, Others are the diseases which affect the respiratory system
(b)Pericardium, Others are the parts of the respiratory system

* Which is the most appropriate statement about breathing?
a) Intake of oxygen to the lungs.
b) Absorbing oxygen and releasing carbon dioxide.
c) Releasing of energy from the nutrients by utilizing oxygen and removal of carbon dioxide.
d) the raising and lowering of the rib.
Ans. c) Releasing of energy from the nutrients by utilizing oxygen and removal of carbon dioxide

* Correct the underlined words of the following statement if it is not correct.
(a) The main constituent for the synthesis of haemoglobin is iron.
(b) Alcohol is formed by the fermentation of milk
(c) Cartilaginous rings help trachea to remain open always.
(d) In plants, lenticel in leaves helps in gaseous exchange.
Ans:
(b) Lactic acid is formed by the fermentation of milk
(d) In plants, Stomata in leaves helps in gaseous exchange.

* Find out the correct statements from the following.
(a) Emphysema is a disease that affects alveoli
(b) Smoking is the main cause of lung cancer.
(c) 28 ATP molecules of energy are released by glycolysis
(d) Krebs cycle takes place in Mitochondria
A) a, b and c are correct
B) a, b and d are correct
C) Only A is right
D) a and b are correct
Ans.
B) a,b and d are correct

* Arrange column B and C of the table according to column A

A

B

C

Pleura

Diaphragm

Alcohol

Anaerobic Respiration

Yeast

30 ATP

Krebs Cycle

Mitochondria

Prevent friction

 

Double layered membrane

28 ATP
Ans.

A

B

C

Pleura

Double layered membrane

Prevent friction

Anaerobic Respiration

Yeast

Alcohol

Krebs Cycle

Mitochondria

28 ATP

* Arrange column B and C of the table according to column A.

A

B

C

Stem

Fermentation

Vital capacity

Carbonic Acid

Emphysema

Tidal volume

Tobacco

Lenticel

Homeostasis

 

Acidity

Gaseous exchange
Ans.

A

B

C

Stem

Lenticel

Gaseous exchange

Carbonic Acid

Acidity

Homeostasis

Tobacco

Emphysema

Vital capacity

* Analyse the relation between respiration and photosynthesis and complete the following table

Indicators

Photosynthesis

Respiration

Functions

 

 

Phases of the reaction

 

 

Substrates

 

 

Products

 

 
Ans.

Indicators

Photosynthesis

Respiration

Functions

Energy stored by the formation of Glucose

Releasing of energy by the depletion of glucose

Phases of the reaction

Light phase and dark phase

Glycolysis and Krebs cycle

Substrates

CO2, Water

Glucose, Oxygen

Products

Glucose, Oxygen

CO2, Water

* Observe the following illustration and answer the questions.
(i) What does the given illustration indicate?
(ii) Complete a and b with the appropriate sentences?
Ans.
(i) Expulsion of carbon dioxide
(ii) b-As carbaminohaemoglobin, formed by combining with haemoglobin
c-As bicarbonates, formed by getting dissolved in water in the RBC

* Based on the indicators, complete the following illustration in relation to Carbon dioxide transport
indicators
(a)7% is transported through this method.
(b) 70% are transported through this method.
Ans.
a)Dissolved in plasma water.
(b)As bicarbonates, formed by getting dissolved in water in the RBC.

* "A child who ate airtight canned food was suffered from bacterial infection"-News
Analyze this news and answer the questions given below.
a) How do these bacteria sustain life?
b) Write the name of the two chemicals produced through this process?
Ans.
(a)Anaerobic respiration
(b)Lactic acid, alcohol
* Leaves get oxygen through stomata. How do the roots and stems get oxygen?
Ans.
The roots and stems get oxygen through lenticels. Exchange of carbon dioxide and oxygen takes place in stems and roots through the cells of lenticels by diffusion.

* Complete the following flowchart in connection with anaerobic respiration in microorganisms
Ans.
(a)Pyruvic acid
(b)Lactic acid
(c)Alcohol, Carbon dioxide

* We use yeast to ferment the batter. After some hours batter becomes soft and puffy.
(a)Write the reason behind batter becoming soft and puffy.
(b)What is the name of this process?
Ans.
(a) Due to the formation of alcohol and carbon dioxide as a result of anaerobic fermentation
(b)Anaerobic fermentation

* Milk is converted into curd
a. Write the name of the chemical reaction in this process?
b. Which bacteria that perform this process?
c. What is the product of this chemical reaction?
Ans.
     a) Lactic acid fermentation
     b) Lactobacillus bacteria
     c) Lactic acid

* A person’s arms get fatigued or tired after he carries weight for a long time.
Explain the reason.
Ans.
When the person carries weight for a long time, energy utilization in muscles increase and the oxygen availability decreases. In such situations, muscle cells produce energy by anaerobic respiration and lactic acid is formed in the muscle cells.

* Complete the missing part of the table given below

 Part of the Respiratory System

 Function

 Alveoli

 (a)

 (b)

 The cavity which connects the nostrils with the pharynx

 (c)

 Muscular wall that helps in thoracic movements

 Pleura

 (d)
Ans.
(a)The part that helps in gaseous exchange
(b)Nasal cavity
(c)Diaphragm
(d)Reduces friction in lungs

* Write examples of three proper health habits which helps us to maintain our respiratory system healthy?
Ans.
Any three suitable health habits-
Avoid bad habits like smoking.
Do not respire polluted air.
Keep personal hygiene.
Do not prone to cough and sneezing.

* Write any two lung diseases which are likely to be associated with people who use tobacco
Ans.
Emphysema, Bronchitis, Lung cancer (Any Two)

* Lung disorders of two persons are given below
Individual A – Vital capacity reduces due to the reduction of the respiratory surface area in the alveoli
Individual B - Swelling of lungs due to the proliferation of germs in the alveoli.
a) Identify the disease condition of patients A and B.
b) How does smoking cause these conditions?
Ans.
a. A-Emphysema
    B-Bronchitis
b) Emphysema -Alveoli rupture due to the loss of elasticity, by the deposition of toxic substances contained in tobacco.
 Bronchitis-Tar, carbon monoxide, etc contained in tobacco leads to the deposition of mucus and the swelling of lungs due to the proliferation of germs in the alveoli.

* Smoking is simultaneous suicide and murder. Evaluate this statement?
Ans.
- The smoker is affected by various lung diseases.
- Persons who inhale smoke also is prone to various lung diseases.

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