Download SCIENCE- NOTES RESPIRATION IN ORGANISMS STD.VII NAME

SCIENCE- NOTES
RESPIRATION IN ORGANISMS
NAME:___________________________
STD.VII
DIV:_____
Q1. Draw the diagram of human respiratory system and explain the function of the
following parts:
i.
ii.
iii.
iv.
v.
Ans.
Nasal cavity
Trachea
Lungs
Bronchioles
Alveoli
i.
ii.
iii.
Nasal cavity: It is the cavity which receives air from the nostrils and passes it into
the trachea.
Trachea: It is also known as the wind pipe. It is guarded by an opening known as
glottis, which gets further covered by epiglottis thus keeping the opening of food
pipe separated from the wind pipe. Trachea later divides into two main sub
branches called as bronchi which enter into the lungs.
Lungs: Lungs are organs of respiration, which are located in the thoracic cavity
on either sides of the heart. The right lung is divided into three lobes and the left
lung into two lobes. They are spongy due to the presence of blood capillaries
filled with blood and air spaces.
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iv.
v.
Bronchioles: Each bronchus which is the part of trachea, divides further into tiny
branches called bronchioles. They are the passages to carry air to the terminating
regions known as alveoli.
Alveoli: Alveoli are tiny air sacs (appearance like a bunch of grapes) which are
made up of single layer membrane. They are involved in exchange of respiratory
gases (O2 and CO2).
Q2. Explain the mechanism of breathing in human beings.
Ans. Breathing which is a physical process involves inhalation and exhalation.
A. INHALATION: It is characterised by downward movement of diaphragm
and the chest cavity moves out which allows the air to enter into the lungs
due to the space created.
B. EXHALATION: During exhalation the ribs move downward and inward.
This causes reduction in the size of the chest cavity and the air is pushed out.
Diaphragm move upward and comes back to its normal dome shaped
structure.
Q3. Explain the process of exchange of gases in insects such as a cockroach.
Ans.
i.
The diagram (A) given below shows the position of small openeings known as
spiracles on the insect’s body
.
(A)
(B)
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ii.
iii.
Diagram (B) shows the tubular system which runs along the body of the
cockroach. These tubular structures are known as trachea.
Trachea open through the spiracles which will help cockroach to exchange the
respiratory gases.
Q4. Justify the statement that composition of inhaled and exhaled air is not the same.
Ans.
INHALED AIR
EXHALED AIR
1.
Inhaled air is rich in oxygen as
compared to exhaled air.
Exhaled air has more carbon dioxide
because the oxygen is used up for
oxidation of food and carbon dioxide is
formed.
2.
Water vapour in inhaled air
varies.
Temperature of inhaled air is
approximately equal to room
temperature.
Exhaled air is saturated with water vapour.
3.
Temperature of exhaled air is same as that
of body temperature.
Q5. Differentiate between aerobic and anaerobic respiration including the chemical
equations.
Ans.
AEROBIC RESPIRATION
ANAEROBIC RESPIRATION
1.
It occurs in presence of oxygen
Occurs in absence of oxygen.
2.
Carbon dioxide and water are the end
products.
End products are- carbon dioxide and
alcohol or lactic acid.
3.
Releases relatively large amount of
energy.
Energy released is less than aerobic
respiration.
4.
It occurs in plants, animals and human
beings.
Carried out by certain bacteria like lactic
acid bacteria and fungus like yeast.
5.
C6H12O6 + 6O2
C6H12O6
6CO2 +
6H2O + Energy
CO2 + Alcohol + Energy
Q6. Explain the following term:
i.
Respiration: It is a vital process in which oxygen rich air is inhaled to oxidise the
food to release energy in the body cells and carbon dioxide rich air is exhaled out
form the body.
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Q7. Frogs can breathe through their skin. List two features of their skin which facilitate
this gaseous exchange?
Ans. Frogs respire through their skin during hibernation.
i. Skin of frogs is soft and moist
ii. It is supplied with large number of blood capillaries.
Q8. i. Label part A and part B in the above diagram.
Ans. Part A- Gills
Part B- Operculum
ii. Explain how these two parts are helpful in respiration in fish.
Ans. Operculum is the covering of gills. Gills are special organs for respiration. Operculum
allows the water to enter and pass over the gills to give oxygen and receive carbon dioxide and
pass out from under the operculum.
Q9. Complete the following table:
Organism
Breathing organ
Characteristics of the
breathing organ
Amoeba or Paramecium
Cell membrane
Diffusion of oxygen and
carbon dioxide through the
cell membrane.
Earthworm
Skin
Skin is moist which helps
in exchange of respiratory
gases.
Tadpoles
Gills
-
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Birds
Lungs
Air filled cavities are
present near the lungs
which make the body of the
birds lighter.
Plants
Stomata
It consists of two guard
cells which control the
opening and closing of
stoma to take in oxygen.
Lenticels
These are small openings
on the bark of the trees
(woody stems).
Q10. Give reasons:
i. Inhaled oxygen is supplied to the body through the blood.
Ans.Red blood cells of blood have a protein known as haemoglobin. It binds with oxygen and acts as a
carrier to provide oxygen to all the parts of the body.
ii. We get cramps when we perform a rigorous physical exercise.
Ans. During a physical exercise body muscles utilise a lot of energy for which they respire fast, but they
do not get sufficient oxygen. Under such conditions, anaerobic respiration takes place which results in
the formation of lactic acid and its accumulation in the muscles. Thus we get cramps due to lactic acid
accumulation in our muscles.
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