RESPIRATION IN ORGANISMS
1. What is respiration?
A. Respiration is the process of taking air ( oxygen) from the environment of the organism, using it for releasing of energy by oxidation of food and expelling the waste products, carbon dioxide (CO2) and water ( H2O). There are two types of respiration:
1. External respiration
2. Internal respiration
3. Differentiate between internal respiration and external respiration.
A. Internal Respiration External Respiration
1. It is a chemical process. It is a physical process.
2. In this process special enzymes are used. Enzymes are not used in this process.
3. It involves oxidation of food particles. It involves exchange of gases.
4. In this process energy is released. In this process energy is not released.
5. Using oxygen, food particles are oxidized- It involves taking of oxygen and
and Carbon dioxide water are formed and- removal of carbon dioxide.
energy is released.
6. It occurs inside the cells. It occurs outside the cells.
4. What is aerobic and anaerobic respiration?
A. The respiration taking place in the presence of oxygen is called aerobic respiration. Or in other words when breakdown of glucose occurs with the use of oxygen, it is called aerobic respiration. It takes place inside the cells.
In the presence of Oxygen
Glucose ---------------------------------
C6 H12 O6 (C3H6O3)
5. What are the difference between aerobic an anaerobic
Aerobic respiration Anaerobic respiration
Breaking down of glucose occurs in the Breaking down of glucose occurs
presence of oxygen. in the absence of oxygen
Glucose is completely oxidized. Glucose is incompletely oxidized.
The end products are carbon dioxide, water The end products are carbon -
and energy. dioxide, ethyl alcohol and energy.
Energy release is more. Energy release is less.
It occurs in all higher organisms. It occurs lower organisms.
( both the equations)
6. With the help of diagram explain the respiratory system of Human.
A. The various organs of respiratory systems in humans are:-
1. Nostrils
2. Nasal cavity
3. Oral cavity
4. Wind pipe
5. Trachea
6. Lungs
7. diaphragm
Human beings take the air through the nostrils. The nostrils are surrounded by hair which prevents the dust particles to enter through the nose. Air from the nostrils enters the nasal cavity which enters the larynx.
From larynx air passes into the wind pipe. The wind pipe is divided into two parts:-
Bronchial tubes:- Each one turns to the lungs of the sides. It is divided into different tubes in the lungs. These terminating air sacs are known as alveoli. The blood capillaries are connected to each of the alveoli. Oxygen is carried to and from by the blood vessels to different parts of the body. From the different parts of the body carbon dioxide is carried by the blood vessels and exchange of gases takes place in the alveoli of the lungs.
8. What is breathing rate?
A. The number of times a person breathes in a minute is known as breathing rate.
9. Why do we feel hungry after a physical exercise?
A. During a physical exercise our body requires extra energy, so we breathe faster. Because of supply of more oxygen to our cells, the rate of breaking down of food or oxidization of food becomes more as a result of which extra energy is obtained by our body. After the exercise all the energy is utilized and the body requires more energy. So, this is why we feel hungry after a physical exercise.
10. Explain the mechanism of breathing in human.
A Breathing is a part of respiration. Breathing means taking in air rich in oxygen and giving out air rich in carbon dioxide with the help of respiratory organs. Taking in of air rich in oxygen into the body is called inhalation and giving out of air rich in carbon dioxide is called exhalation. The respiratory organs of humans are nostrils, Nasal cavity, oral cavity, wind pipe, trachea, lungs and diaphragm.
When we inhale air, it passes through our nostrils into the nasal cavity. From the nasal cavity, the air reaches our lungs through the windpipe. Lungs are present in the chest cavity. This cavity is surrounded by ribs on the sides. A large, muscular sheet called diaphragm forms the floor of the chest cavity. During inhalation the ribs move in a upward direction and the diaphragm moves in a downward direction. This movement expands the space in our chest cavity and air rush into the lungs. The lungs get filled with air. During inhalation the size of the chest increases. During exhalation, the ribs move in downward direction and the diaphragm move in upward direction. Here the air is exhaled out of the lungs. During exhalation the size of the chest decreases.
11. How do the respiration takes place in (i) Earth worm ii) Frog iii) Fish?
A. Respiration in Earthworm: An earthworm is a terrestrial organism. It breathes through the moist skin or skin surface.
Respiration in Frog: A frog is an amphibian. On land it breathes through a pair of lungs like any other higher organisms. In water it breathes through its moist slippery skin.
Respiration in Fish: A fish is an aquatic organism. It respires through the gills present on the sides. They take in oxygen dissolved in water.
12. Explain about the respiration in cockroaches.
A. A cockroach has small openings called spiracles present on the sides of its body. It has a network of air tubes called tracheae for gas exchange. Oxygen rich air rushes through the spiracles into the tracheal tubes diffuses into the body tissue and reaches every cell of the body. Similarly, carbon dioxide from the cell goes into the tracheal tubes and moves out through spiracles. These air tubes or tracheal tubes are found only in insects and not in any other group of animals.
13. Explain about the respiration in plants?
A. Like other animals plants also respire. Plants respire through stomata generally present on the lower surface of the leaves. They also respire through the stems and roots. They contain small openings through which air enter it. Soil contains trapped air.
NCERT BOOK QUESTIONS
Q.1: Why does athlete breathe faster and deeper than usual after finishing the race?
Ans: An athlete needs more energy during the race and after. Since demand for the energy is high, the breakdown of food must be speeded up. This requires more oxygen to be supplied. This is why an athlete not only breathes fast, but also take deep breathes than usual after finishing the race and thus inhale more oxygen.
Q.2. Given before.
Q.3: Why we often sneeze when we inhale a lot of dust-laden air?
Ans: The air around us has various types of unwanted suspended particles like- smoke, dust, pollens etc. When we inhale these particles get trapped in the hair present in our nasal cavity. However, sometimes these particles may get past the hair present in our nasal cavity. Then they irritate the lining of the cavity as a result of which we sneeze. Sneezing expels these foreign particles from the inhaled air and a dust-free, clean air enters our body.
Q.5: Tick the correct answer:
A. In cockroaches air enters the body through
i. lungs ii. Gills iii. Spiracles iv. Skin
B. During heavy exercise, we get cramps in the legs due to the accumulation of
i. carbon dioxide ii. lactic acid iii. Alcohol iv. Water
C. Normal range of breathing rate per minute in an average adult person at rest is -
i. 9-12 ii. 15-18 iii. 21-24 iv. 30-33
D. During exhalation, the ribs
i. move outwards ii. move downwards iii. move upward iv. do not move at all
Q.6: Match the items in column I with those in column II
Column I
Column II
(a) Yeast
(b) Diaphragm
(c) Skin
(d) Leaves
(e) Fish
(f) Frog
(i) Earthworm
(ii) Gills
(iii) Alcohol
(iv) Chest cavity
(v) Stomata
(vi) Lungs and skin
(vii) Trachea
Ans: (a)-iii (b)-iv (c)-I (d)-v (e)-ii (f)-vi
Q.7: Mark true (T) and false (F)
(i) During heavy exercise the breathing rate of a person slows down.
(ii) Plants carry out photosynthesis only during the day and respiration only at night.
(iii) Frogs breathe through their skins as well as their lungs.
(iv) The fishes have lungs for respiration.
(v) The size of the chest cavity increases during the inhalation.
Ans: (i)F (ii)F (iii)T (iv)F (v)T
EXTRA QUESTIONS
Q.1: Why we get muscle cramps after heavy exercise?
Ans: During heavy exercise the demand for energy is high. But the supply of oxygen to produce energy is limited. Then anaerobic respiration takes place in the muscle cells to fulfill the demand of energy.
Glucose in absence of oxygen > Lactic Acid + Energy
The cramps occur only when the muscle cells respire anaerobically. The partial breakdown of glucose produces lactic acid. The accumulation of lactic acid causes muscle cramps.
Q.2: Why we feel hungry after a physical activity?
Ans: During a physical activity we need more energy. Whenever a person needs extra energy he/she breathes faster. As a result, more oxygen is supplied to our cells. It speeds up the breakdown of food and more energy is released. Due to rapid breakdown of food we feel hungry.
Q.3: How does the exchange of gases occur in breathing?
Ans: When we inhale air it passes through our nostrils to nasal cavity. From nasal cavity the air reaches our lungs. The exhaled air follows same route to go out. Breathing in and out involves the movement of the diaphragm and the rib cage.
Fig: Inhalation and Exhalation
Q.4: Write short notes on -
(i) Inhalation and Exhalation
(ii) Gills
Ans:
(i) Inhalation: The process of taking in of air rich in oxygen into the body is called ‘inhalation’. During inhalation, ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. Exhalation: The process of giving out of air giving out of air rich in carbon dioxide is known as ‘exhalation’. During exhalation, ribs move down and inwards while, diaphragm moves up to its former position. This movement reduces the size of our chest cavity and air is pushed out
(ii) Gills: Gills in fish help them to use oxygen dissolved in water and thus, help them in breathing. Gills are projections of their skin. These are well supplied with blood vessels for exchange of gases.
Q.5: Do the plants also respire?
Ans: Like all other organisms, plants also respire for their survival. They take oxygen from the air and give out carbon dioxide. In the cells oxygen is used to breakdown glucose into carbon dioxide and water as in other organisms.
Q.6: How do the plants breathe in oxygen?
Ans: In plants each part can independently take in oxygen from air and give out carbon dioxide. Leaves of the plants have tiny pores called ‘stomata’ for exchange of oxygen and carbon dioxide. Roots take up air from the pores (air spaces) present between the soil particles.
Objective Questions
Q.1: Fill in the blanks:
(a) Breathing is a part of ________.
(b) The food has _______ which is released during _____.
(c) Yeasts can survive in the absence of air. They are called ________.
(d) All living organisms ________ to get energy from food.
(e) ________ are used in wine, beer industry and bakery.
(f) Blood in our body is oxygenated by the organ known as ________.
(g) Breathing rate in human beings in normal condition is ________ times in a minute.
(h) The site of cellular respiration is ________.
(i) Cockroach breath through _________.
(j) Earthworms breathe through their _________.
(k) The process of breakdown of food in the cell with the release of energy is called ____________.
Ans: (a) respiration (b) stored energy, respiration (c) anaerobes (d) respire (e) yeasts (f) lungs (g) 15-18 (h) mitochondria (i) spiracles (j) skin (k) cellular respiration.
1. What is respiration?
A. Respiration is the process of taking air ( oxygen) from the environment of the organism, using it for releasing of energy by oxidation of food and expelling the waste products, carbon dioxide (CO2) and water ( H2O). There are two types of respiration:
1. External respiration
2. Internal respiration
3. Differentiate between internal respiration and external respiration.
A. Internal Respiration External Respiration
1. It is a chemical process. It is a physical process.
2. In this process special enzymes are used. Enzymes are not used in this process.
3. It involves oxidation of food particles. It involves exchange of gases.
4. In this process energy is released. In this process energy is not released.
5. Using oxygen, food particles are oxidized- It involves taking of oxygen and
and Carbon dioxide water are formed and- removal of carbon dioxide.
energy is released.
6. It occurs inside the cells. It occurs outside the cells.
4. What is aerobic and anaerobic respiration?
A. The respiration taking place in the presence of oxygen is called aerobic respiration. Or in other words when breakdown of glucose occurs with the use of oxygen, it is called aerobic respiration. It takes place inside the cells.
In the presence of Oxygen
Glucose ---------------------------------
C6 H12 O6 (C3H6O3)
5. What are the difference between aerobic an anaerobic
Aerobic respiration Anaerobic respiration
Breaking down of glucose occurs in the Breaking down of glucose occurs
presence of oxygen. in the absence of oxygen
Glucose is completely oxidized. Glucose is incompletely oxidized.
The end products are carbon dioxide, water The end products are carbon -
and energy. dioxide, ethyl alcohol and energy.
Energy release is more. Energy release is less.
It occurs in all higher organisms. It occurs lower organisms.
( both the equations)
6. With the help of diagram explain the respiratory system of Human.
A. The various organs of respiratory systems in humans are:-
1. Nostrils
2. Nasal cavity
3. Oral cavity
4. Wind pipe
5. Trachea
6. Lungs
7. diaphragm
Human beings take the air through the nostrils. The nostrils are surrounded by hair which prevents the dust particles to enter through the nose. Air from the nostrils enters the nasal cavity which enters the larynx.
From larynx air passes into the wind pipe. The wind pipe is divided into two parts:-
Bronchial tubes:- Each one turns to the lungs of the sides. It is divided into different tubes in the lungs. These terminating air sacs are known as alveoli. The blood capillaries are connected to each of the alveoli. Oxygen is carried to and from by the blood vessels to different parts of the body. From the different parts of the body carbon dioxide is carried by the blood vessels and exchange of gases takes place in the alveoli of the lungs.
8. What is breathing rate?
A. The number of times a person breathes in a minute is known as breathing rate.
9. Why do we feel hungry after a physical exercise?
A. During a physical exercise our body requires extra energy, so we breathe faster. Because of supply of more oxygen to our cells, the rate of breaking down of food or oxidization of food becomes more as a result of which extra energy is obtained by our body. After the exercise all the energy is utilized and the body requires more energy. So, this is why we feel hungry after a physical exercise.
10. Explain the mechanism of breathing in human.
A Breathing is a part of respiration. Breathing means taking in air rich in oxygen and giving out air rich in carbon dioxide with the help of respiratory organs. Taking in of air rich in oxygen into the body is called inhalation and giving out of air rich in carbon dioxide is called exhalation. The respiratory organs of humans are nostrils, Nasal cavity, oral cavity, wind pipe, trachea, lungs and diaphragm.
When we inhale air, it passes through our nostrils into the nasal cavity. From the nasal cavity, the air reaches our lungs through the windpipe. Lungs are present in the chest cavity. This cavity is surrounded by ribs on the sides. A large, muscular sheet called diaphragm forms the floor of the chest cavity. During inhalation the ribs move in a upward direction and the diaphragm moves in a downward direction. This movement expands the space in our chest cavity and air rush into the lungs. The lungs get filled with air. During inhalation the size of the chest increases. During exhalation, the ribs move in downward direction and the diaphragm move in upward direction. Here the air is exhaled out of the lungs. During exhalation the size of the chest decreases.
11. How do the respiration takes place in (i) Earth worm ii) Frog iii) Fish?
A. Respiration in Earthworm: An earthworm is a terrestrial organism. It breathes through the moist skin or skin surface.
Respiration in Frog: A frog is an amphibian. On land it breathes through a pair of lungs like any other higher organisms. In water it breathes through its moist slippery skin.
Respiration in Fish: A fish is an aquatic organism. It respires through the gills present on the sides. They take in oxygen dissolved in water.
12. Explain about the respiration in cockroaches.
A. A cockroach has small openings called spiracles present on the sides of its body. It has a network of air tubes called tracheae for gas exchange. Oxygen rich air rushes through the spiracles into the tracheal tubes diffuses into the body tissue and reaches every cell of the body. Similarly, carbon dioxide from the cell goes into the tracheal tubes and moves out through spiracles. These air tubes or tracheal tubes are found only in insects and not in any other group of animals.
13. Explain about the respiration in plants?
A. Like other animals plants also respire. Plants respire through stomata generally present on the lower surface of the leaves. They also respire through the stems and roots. They contain small openings through which air enter it. Soil contains trapped air.
NCERT BOOK QUESTIONS
Q.1: Why does athlete breathe faster and deeper than usual after finishing the race?
Ans: An athlete needs more energy during the race and after. Since demand for the energy is high, the breakdown of food must be speeded up. This requires more oxygen to be supplied. This is why an athlete not only breathes fast, but also take deep breathes than usual after finishing the race and thus inhale more oxygen.
Q.2. Given before.
Q.3: Why we often sneeze when we inhale a lot of dust-laden air?
Ans: The air around us has various types of unwanted suspended particles like- smoke, dust, pollens etc. When we inhale these particles get trapped in the hair present in our nasal cavity. However, sometimes these particles may get past the hair present in our nasal cavity. Then they irritate the lining of the cavity as a result of which we sneeze. Sneezing expels these foreign particles from the inhaled air and a dust-free, clean air enters our body.
Q.5: Tick the correct answer:
A. In cockroaches air enters the body through
i. lungs ii. Gills iii. Spiracles iv. Skin
B. During heavy exercise, we get cramps in the legs due to the accumulation of
i. carbon dioxide ii. lactic acid iii. Alcohol iv. Water
C. Normal range of breathing rate per minute in an average adult person at rest is -
i. 9-12 ii. 15-18 iii. 21-24 iv. 30-33
D. During exhalation, the ribs
i. move outwards ii. move downwards iii. move upward iv. do not move at all
Q.6: Match the items in column I with those in column II
Column I
Column II
(a) Yeast
(b) Diaphragm
(c) Skin
(d) Leaves
(e) Fish
(f) Frog
(i) Earthworm
(ii) Gills
(iii) Alcohol
(iv) Chest cavity
(v) Stomata
(vi) Lungs and skin
(vii) Trachea
Ans: (a)-iii (b)-iv (c)-I (d)-v (e)-ii (f)-vi
Q.7: Mark true (T) and false (F)
(i) During heavy exercise the breathing rate of a person slows down.
(ii) Plants carry out photosynthesis only during the day and respiration only at night.
(iii) Frogs breathe through their skins as well as their lungs.
(iv) The fishes have lungs for respiration.
(v) The size of the chest cavity increases during the inhalation.
Ans: (i)F (ii)F (iii)T (iv)F (v)T
EXTRA QUESTIONS
Q.1: Why we get muscle cramps after heavy exercise?
Ans: During heavy exercise the demand for energy is high. But the supply of oxygen to produce energy is limited. Then anaerobic respiration takes place in the muscle cells to fulfill the demand of energy.
Glucose in absence of oxygen > Lactic Acid + Energy
The cramps occur only when the muscle cells respire anaerobically. The partial breakdown of glucose produces lactic acid. The accumulation of lactic acid causes muscle cramps.
Q.2: Why we feel hungry after a physical activity?
Ans: During a physical activity we need more energy. Whenever a person needs extra energy he/she breathes faster. As a result, more oxygen is supplied to our cells. It speeds up the breakdown of food and more energy is released. Due to rapid breakdown of food we feel hungry.
Q.3: How does the exchange of gases occur in breathing?
Ans: When we inhale air it passes through our nostrils to nasal cavity. From nasal cavity the air reaches our lungs. The exhaled air follows same route to go out. Breathing in and out involves the movement of the diaphragm and the rib cage.
Fig: Inhalation and Exhalation
Q.4: Write short notes on -
(i) Inhalation and Exhalation
(ii) Gills
Ans:
(i) Inhalation: The process of taking in of air rich in oxygen into the body is called ‘inhalation’. During inhalation, ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. Exhalation: The process of giving out of air giving out of air rich in carbon dioxide is known as ‘exhalation’. During exhalation, ribs move down and inwards while, diaphragm moves up to its former position. This movement reduces the size of our chest cavity and air is pushed out
(ii) Gills: Gills in fish help them to use oxygen dissolved in water and thus, help them in breathing. Gills are projections of their skin. These are well supplied with blood vessels for exchange of gases.
Q.5: Do the plants also respire?
Ans: Like all other organisms, plants also respire for their survival. They take oxygen from the air and give out carbon dioxide. In the cells oxygen is used to breakdown glucose into carbon dioxide and water as in other organisms.
Q.6: How do the plants breathe in oxygen?
Ans: In plants each part can independently take in oxygen from air and give out carbon dioxide. Leaves of the plants have tiny pores called ‘stomata’ for exchange of oxygen and carbon dioxide. Roots take up air from the pores (air spaces) present between the soil particles.
Objective Questions
Q.1: Fill in the blanks:
(a) Breathing is a part of ________.
(b) The food has _______ which is released during _____.
(c) Yeasts can survive in the absence of air. They are called ________.
(d) All living organisms ________ to get energy from food.
(e) ________ are used in wine, beer industry and bakery.
(f) Blood in our body is oxygenated by the organ known as ________.
(g) Breathing rate in human beings in normal condition is ________ times in a minute.
(h) The site of cellular respiration is ________.
(i) Cockroach breath through _________.
(j) Earthworms breathe through their _________.
(k) The process of breakdown of food in the cell with the release of energy is called ____________.
Ans: (a) respiration (b) stored energy, respiration (c) anaerobes (d) respire (e) yeasts (f) lungs (g) 15-18 (h) mitochondria (i) spiracles (j) skin (k) cellular respiration.