3. We have just studied that digested food is
assimilated into the body of the living organisms.
The assimilated food is used mainly for two
purposes:
Assimilated food is used as a fuel to get energy
for various life processes, and
Assimilated food is used as a material for the
growth and repair of the body.
4. We will now describe how energy is released
from the food which is absorbed and
assimilated in the cells of the body. Please
note that food is the 'fuel’ for energy
production in cells. Let us see how energy is
actually obtained.
Most living things need oxygen ( of air) to
obtain energy from food.
5. • This oxygen reacts with the food molecules
(like glucose) present in the body cells and
burns them slowly to release energy. The
energy thus released is stored in ATP
molecules in the cells. The body can use this
stored energy whenever it wants to do so.
• The process of releasing energy from
6.
7.
8.
9. The mechanism by which organisms obtain oxygen
from the air and release carbon dioxide is called
breathing. Respiration is a more complex process.
Respiration includes breathing as well as the
oxidation of food in cells of organism to release
energy. Breathing is a physical process whereas
respiration also includes biochemical process of
oxidation of food.
10. The process of breathing involves the lungs of
the organism whereas the process of
respiration also involves the mitochondria in
the cells where food oxidised to release
energy.
Respiration is actually a biochemical process
which occurs in stages and requires many
enzymes. The main purpose of respiration is
the release of energy from the oxidation of
simple food molecules like glucose. The energy
released during respiration is used for
carrying out the biological functions which are
necessary for the maintenance of life and
survival of an organism.
11. Please note that respiration is just
opposite of photosynthesis. This is
because photosynthesis makes food
(like glucose) by using carbon
dioxide, water and sunlight
energy, and releasing oxygen;
whereas respiration breaks food (like
glucose) by using oxygen, and
releasing carbon dioxide, water and
energy.
12. There are two types of respiration:
A. Aerobic Respiration
B. Anaerobic Respiration
13. Aerobic Respiration
The respiration which uses oxygen is called
aerobic respiration. It is called aerobic
respiration because it uses air which contains
oxygen (aerobic 'means ‘with air’) . In aerobic
respiration, the glucose food is completely
broken down into carbon dioxide and water by
oxidation. Aerobic respiration produces a
considerable amount of energy for use by the
organism which gets stored in the ATP
molecules.
14. The energy released during aerobic respiration is
used by the organism. Most of the living organisms
carry out aerobic respiration (by using oxygen of
air). For example, humans (man), dogs cats, lions,
elephants, cows, buffaloes, goat, deer, birds,
lizards, snakes, earthworms, frogs, fish, and
insects aerobic respiration by using oxygen of air
(to obtain energy).
15. The respiration which takes place without oxygen
is called anaerobic respiration. It is called
anaerobic respiration because it takes place
without air which contains oxygen(‘anaerobic’
means ;without air’). The microscopic organisms
like yeast and some bacteria obtain energy by
anaerobic respiration (which is called
fermentation). In anaerobic respiration, the
micro-organisms like yeast break down glucose
(food) into ethanol and carbon dioxide, and
release energy.
16. Aerobic respiration
1. Aerobic respiration
takes place in the
presence of oxygen.
2. Complete breakdown
of food occurs in
aerobic respiration.
3. The end products in
aerobic respiration are
carbon dioxide and
water.
4. Aerobic respiration
produces a
considerable amount
of energy.
1. Anaerobic respiration
takes place in the absence
of oxygen.
2. Partial breakdown of food
occurs in anaerobic
respiration.
3. The end products in
anaerobic respiration may
be ethanol and carbon
dioxide (as in yeast
plants),or lactic acid (as in
animal muscles).
4. Much less energy is
produced in anaerobic
respiration.
Anaerobic respiration
19. Passageway for respiration
Receptors for smell
Filters incoming air to filter larger foreign
material
Moistens and warms incoming air
Resonating chambers for voice
Upper Respiratory Tract Functions
21. Lower Respiratory Tract
Functions:
Larynx: maintains an open airway, routes food
and air appropriately, assists in sound
production
Trachea: transports air to and from lungs
Bronchi: branch into lungs
Lungs: transport air to alveoli for gas exchange
23. In human beings, air is taken into the body
through the nostrils. The air passing through
the nostrils is filtered by fine hairs that line
the passage. The passage is also lined with
mucus which helps in this process. From here,
the air passages through the throat and into
the lungs. Rings of cartilage are present in the
throat. These ensure that the air-passage
does not collapse.
