Respiration is defined as the burning of food molecules to release energy in the form of ATP or ADP. There are two types of respiration - aerobic respiration, which uses oxygen and produces more energy, and anaerobic respiration, which does not use oxygen and produces less energy. Respiration occurs in plants through their roots, stems, and leaves, and in animals through specialized respiratory systems like lungs. The respiratory system in humans includes the nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, and lungs.

3. Earlier the intake of O
Earlier the intake of O2
2 and exhalation of CO
and exhalation of CO2
2 was
was
considered as respiration. However this defination was
considered as respiration. However this defination was
incomplete. So now a days respiration is defined as
incomplete. So now a days respiration is defined as burning
burning
food molecules to release energy in the form of ATP or ADP.
food molecules to release energy in the form of ATP or ADP.
C
C6
6H
H12
12O
O6
6 + 6O
+ 6O2
2 --------- 6CO
→
--------- 6CO
→ 2
2 + 6H
+ 6H2
2O + Energy
O + Energy
Respiration
Respiration...
...

4. Aerobic respiration:
Aerobic respiration: When O
When O2
2 is used for respiration it is called
is used for respiration it is called
aerobic respiration.
aerobic respiration.
During this kind of respiration the CO
During this kind of respiration the CO2
2 and H
and H2
2O are
O are
completely broken down
completely broken down
Amount of energy produced is (38 ATP)
Amount of energy produced is (38 ATP)
Glucose---------------> Pyruvate------------------------>6H
Glucose---------------> Pyruvate------------------------>6H2
2O+ 6CO
O+ 6CO2
2+Energy
+Energy
Note: Conversion of glucose to pyruvate is called
Note: Conversion of glucose to pyruvate is called Glycolysis.
Glycolysis.
The above reaction takes place in
The above reaction takes place in mitochondria
mitochondria.
.
Types of respiration...

5. Anaerobic Respiration:
Anaerobic Respiration: When food is oxidised without using O
When food is oxidised without using O2
2 ,
,
the respiration is called anaerobic respiration.
the respiration is called anaerobic respiration.
During this kind of respiration the food molecules do
During this kind of respiration the food molecules do
not go under complete oxidation.
not go under complete oxidation.
Amount of energy produced is very less. (2ATP).
Amount of energy produced is very less. (2ATP).
Glucose--------------> Pyruvate------------->Ethanol + CO
Glucose--------------> Pyruvate------------->Ethanol + CO2
2 + Energy
+ Energy
(Alcohol Fermentation; Takes place in Yeast)
(Alcohol Fermentation; Takes place in Yeast)
Glucose--------------> Pyruvate------------>Lactic Acid + Energy
Glucose--------------> Pyruvate------------>Lactic Acid + Energy
(Lactic acid fermentation; Takes place in muscle cells)
(Lactic acid fermentation; Takes place in muscle cells)
Note:
Note: It takes place in the cytoplasm of the cell.
It takes place in the cytoplasm of the cell.

6. Breathing
Breathing Respiration
Respiration
It is an extracellular process
It is an extracellular process
It is both an extracellular and
It is both an extracellular and
intracellular process.
intracellular process.
It does not involve enzyme action.
It does not involve enzyme action.
It requires number of enzymes for
It requires number of enzymes for
oxidation of food. Eg. Peroxidases
oxidation of food. Eg. Peroxidases
It does not release energy rather it
It does not release energy rather it
consumes energy.
consumes energy.
It releases energy
It releases energy
It is confined to certain organs only.
It is confined to certain organs only. It occurs in all the cells of the body.
It occurs in all the cells of the body.
Note: All the cells use ATP for all the energy required.
Note: All the cells use ATP for all the energy required.
Every process , even nerve impulses use ATP.
Every process , even nerve impulses use ATP.

7. Respiration in plants:
Respiration in plants:
Most of the big plants are branched and cover more area. This is
Most of the big plants are branched and cover more area. This is
because they need more CO
because they need more CO2
2 and other materials as compared to
and other materials as compared to
small trees. This indicates that the plants take in their resources
small trees. This indicates that the plants take in their resources
through simple diffusion and osmosis(in roots for absorbing
through simple diffusion and osmosis(in roots for absorbing
water).
water).
O
O2
2 in environment is taken in the plant through the following
in environment is taken in the plant through the following
parts of a plant:
parts of a plant:
Stomata in leaves
Stomata in leaves
Lenticles in stems
Lenticles in stems
General surface of the roots.
General surface of the roots.

8. Respiration in roots:
Respiration in roots:
Plants take oxygen with the help of roots. Roots are provided with
Plants take oxygen with the help of roots. Roots are provided with
root hair which enhances the area for the absorption of minerals.
root hair which enhances the area for the absorption of minerals.
The root hair take in O
The root hair take in O2
2 with the help of diffusion. The CO
with the help of diffusion. The CO2
2
molecules generated during respiration are also excreted through
molecules generated during respiration are also excreted through
the same way. Note: plants take in O
the same way. Note: plants take in O2
2 for respiration whereas take
for respiration whereas take
in CO
in CO2
2 for the process of photosynthesis.
for the process of photosynthesis.
Many of us might also wonder that water is necessary for plants
Many of us might also wonder that water is necessary for plants
but when we over-irrigate the plant;
but when we over-irrigate the plant; it dies within few days.
it dies within few days.
This is because water expels the O
This is because water expels the O2
2 molecules out of the soil hence
molecules out of the soil hence
decreasing the O
decreasing the O2
2 intake of plant.
intake of plant.

9. Respiration in stems:
Respiration in stems:
The green stems basically of the plants have stomata in them
The green stems basically of the plants have stomata in them
whereas the hard and woody stems(brown in color) have lenticels
whereas the hard and woody stems(brown in color) have lenticels
in them.
in them.
In green stemmed plants stomata is responsible for the gaseous
In green stemmed plants stomata is responsible for the gaseous
exchange through stem whereas lenticels are responsible for
exchange through stem whereas lenticels are responsible for
gaseous exchange woody plants.
gaseous exchange woody plants.

10. Respiration in leaves
Respiration in leaves
The exchange of respiratory gasses in the leaves take place by
The exchange of respiratory gasses in the leaves take place by
the process of diffusion in stomata.
the process of diffusion in stomata.
Respiration in leaves occur during the daytime as well as at
Respiration in leaves occur during the daytime as well as at
night. Whereas photosynthesis occurs only during the daytime.
night. Whereas photosynthesis occurs only during the daytime.
Respiration takes place both in presence as well as absence of
Respiration takes place both in presence as well as absence of
sunlight. During daytime the process of photosynthesis also take
sunlight. During daytime the process of photosynthesis also take
place. Due to this the CO
place. Due to this the CO2
2 produced during respiration is used up
produced during respiration is used up
for the process of photosynthesis. But during night the process of
for the process of photosynthesis. But during night the process of
photosynthesis stop hence a only
photosynthesis stop hence a only CO
CO2
2 is produced but it is not
is produced but it is not
utilised.
utilised.

11. Respiration in Animals
Respiration in Animals
The process of respiration takes place in animals too. As the animals move ,
The process of respiration takes place in animals too. As the animals move ,
they require more energy as compared to plants. Eg. Amoeba, Paramecium,
they require more energy as compared to plants. Eg. Amoeba, Paramecium,
Hydra, etc..
Hydra, etc..
Single – celled organisms perform the task of respiration by the process of
Single – celled organisms perform the task of respiration by the process of
diffusion. But multi cellular organisms require a proper system for the
diffusion. But multi cellular organisms require a proper system for the
exchange of gasses.
exchange of gasses.
Many multicellular organisms use another methods for respiration.
Many multicellular organisms use another methods for respiration.
i) In earthworm respiration takes place through the body surface
i) In earthworm respiration takes place through the body surface
(skin) .
(skin) .
ii) In insects like grasshopper air tubes or trachea are responsible
ii) In insects like grasshopper air tubes or trachea are responsible
for respiration
for respiration.

12. Respiratory System In Humans
Respiratory System In Humans
Nostrils and nasal cavity
Nostrils and nasal cavity
Nostrils are the nasal openings through which air
Nostrils are the nasal openings through which air
draws
draws to nasal cavity. The nasal cavity and the mouth
to nasal cavity. The nasal cavity and the mouth
are separated by a bony plate.
are separated by a bony plate.
The nasal passages are aligned by ciliated epithelium
The nasal passages are aligned by ciliated epithelium
and mucus secreting cells.
and mucus secreting cells. Both cilia and mucus check
Both cilia and mucus check
the entry of dust particles and microbes.
the entry of dust particles and microbes.
Mucus also help in
Mucus also help in warming the air and moistening it
warming the air and moistening it .
.
Many of us might have noticed that nasal discharge is
Many of us might have noticed that nasal discharge is
there during the cold. That nasal discharge is actually
there during the cold. That nasal discharge is actually
the mucus that is secreted by our body just to maintain
the mucus that is secreted by our body just to maintain
the temperature inside the body.
the temperature inside the body.

13. Pharynx
Pharynx
It is a common passage for air and food. It leads into trachea
It is a common passage for air and food. It leads into trachea
(Wind pipe) as well as oesoghagus (food pipe).
(Wind pipe) as well as oesoghagus (food pipe).
Due to this there must be an organ to prevent the entry of food in
Due to this there must be an organ to prevent the entry of food in
lungs and air in stomach.
lungs and air in stomach.
This function is performed by the epiglottis .
This function is performed by the epiglottis .

14. Trache and Bronchi:
Trache and Bronchi:
i)The human trachea is about 10 to 11 cm in length. Its walls are
i)The human trachea is about 10 to 11 cm in length. Its walls are
provided with cartilaginous rings which prevent the trachea
provided with cartilaginous rings which prevent the trachea
from collapsing even when there is not much air in it.
from collapsing even when there is not much air in it.
ii) The human trachea is made up by ciliated epithelium and
ii) The human trachea is made up by ciliated epithelium and
mucus secreting cells. (Extra point; not for boards)
mucus secreting cells. (Extra point; not for boards)
iii) On entering the thoracic cavity trachea divides into bronchi.
iii) On entering the thoracic cavity trachea divides into bronchi.

15. Bronchioles And Alveoli :
Bronchioles And Alveoli :
Within the lungs each bronchus divides further into bronchiole
Within the lungs each bronchus divides further into bronchiole
These bronchioles further divide and redivide and end into a
These bronchioles further divide and redivide and end into a
cluster of tiny air chambers called alveoli.
cluster of tiny air chambers called alveoli.
Alveoli are functional units of lungs as each alveoli is having a
Alveoli are functional units of lungs as each alveoli is having a
capillary where the exchange of gasses take place with the help
capillary where the exchange of gasses take place with the help
of diffusion.
of diffusion.
Extra part: Each bronchus with
Extra part: Each bronchus with
its branches is called bronchial
its branches is called bronchial
tree.
tree.

16. Lungs:
Lungs:
The lungs are the pair of highly elastic bag like organs. They
The lungs are the pair of highly elastic bag like organs. They
are situated in the thoracic cavity. The lower surface of lungs
are situated in the thoracic cavity. The lower surface of lungs
is covered by the diaphragm which forms the floor of thoracic
is covered by the diaphragm which forms the floor of thoracic
cavity. Lungs play a
cavity. Lungs play a
very crucial part in respiration.
very crucial part in respiration.
It is the place where mucus secreting ends .
It is the place where mucus secreting ends .
Also there is some extra amount of air
Also there is some extra amount of air
kept in our lungs too as is there is shortage
kept in our lungs too as is there is shortage
of this air; the lungs will collapse due to
of this air; the lungs will collapse due to
suction in them and the person will die.
suction in them and the person will die.

17. Mechanism of Breathing:
Mechanism of Breathing:
Breathing is a mechanical process which involves two processes:
Breathing is a mechanical process which involves two processes:
inhalation and exhalation.
inhalation and exhalation.
Inhalation:
Inhalation:
During inhalation the diaphragm expands creating a suction in the
During inhalation the diaphragm expands creating a suction in the
lungs causing the air to move in through nostrils, trachea, bronchi. As
lungs causing the air to move in through nostrils, trachea, bronchi. As
discussed prior the walls of alveoli are one cell thick and the O
discussed prior the walls of alveoli are one cell thick and the O2
2 diffuses
diffuses
into the blood.
into the blood.
Exhalation:
Exhalation:
As the result of cellular respiration of nutrition in cells CO
As the result of cellular respiration of nutrition in cells CO2
2 is generated
is generated
which is taken back to the lungs via blood and again diffusion takes
which is taken back to the lungs via blood and again diffusion takes
place as the concentration of CO
place as the concentration of CO2
2 is more in the blood rather than the air
is more in the blood rather than the air
present in lungs.
present in lungs.

18. Exchange Of Gasses:
Exchange Of Gasses:
In humans the respiratory pigment is haemoglobin which has high affinity for
In humans the respiratory pigment is haemoglobin which has high affinity for
O
O2
2 . This pigment is present in RBC’ s . O
. This pigment is present in RBC’ s . O2
2 combines with haemoglobin (note it does
combines with haemoglobin (note it does
not mixes with the blood) and gets transported to the whole body.
not mixes with the blood) and gets transported to the whole body.
But CO
But CO2
2 is more soluble in water so it gets dissolved in the blood and gets
is more soluble in water so it gets dissolved in the blood and gets
transported .
transported .
In this exchange the blood takes up O
In this exchange the blood takes up O2
2 from the alveolar air present in the lungs.
from the alveolar air present in the lungs.
This exchange of gasses result in the oxygenation of blood.
This exchange of gasses result in the oxygenation of blood.
Also there is a process by which exchange of gasses take place in the tissues and
Also there is a process by which exchange of gasses take place in the tissues and
the blood.
the blood.
The body cells do work continuously. When the oxygen rich blood come in contact
The body cells do work continuously. When the oxygen rich blood come in contact
with them ; the process of diffusion take place as the blood has higher
with them ; the process of diffusion take place as the blood has higher
concentration of O
concentration of O2
2 as compared to cell. So O
as compared to cell. So O2
2 diffuses into the cell and CO
diffuses into the cell and CO2
2 is
is
expelled out of the cell.
expelled out of the cell.

24. Credits:
Credits:
Resources collected by: Akshath Goyal
Resources collected by: Akshath Goyal
PPT made by:
PPT made by: Akshath Goyal
Akshath Goyal
Explanation of the slides by:Akshath Goyal
Explanation of the slides by:Akshath Goyal
Class 10, Chapter 6 (respiration)
Class 10, Chapter 6 (respiration)