Class-7 Science Chapter-10 Respiration in Organisms, Additional Exercises in line with NCERT book / CBSE Syllabus
Chapter 10
Respiration in
Organisms
Exercises from
textbook
Additional
Exercises
Activities/Projects
Additional Exercises
Choose the correct answer:
1-
Which
of the following activity damages lungs and is linked to cancer
a.
Breathing
b.
Running
c.
Smoking
(√)
d.
Yoga
2- What is the percentage of Oxygen and
Carbon dioxide in inhaled air
a.
21%
oxygen & 0.04 % carbon dioxide (√)
b.
100
% Oxygen & No carbon dioxide
c.
50%
oxygen & 50% carbon dioxide
d.
16.4%
oxygen & 4.4% carbon
3- What is the percentage of Oxygen and
Carbon dioxide in exhaled air
a.
21%
oxygen & 0.04 % carbon dioxide
b.
100
% carbon dioxide & No oxygen
c.
50%
oxygen & 50% carbon dioxide
d.
16.4%
oxygen & 4.4% carbon (√)
4- Which of the following organism does not
have lungs in its chest cavity?
a.
Lizard
b.
Birds
c.
Snake
d.
None
of the above (√)
5-
Which
of the following organ is present in the chest cavity
a.
Lunch
(√)
b.
Stomach
c.
Kidney
d.
Gallbladder
6-
The
number of times a person breathes in a minute is termed as
a.
Heart
rate
b.
Pulse
beat
c.
Breathing
rate (√)
d.
None
of the above
7-
A
breath means
a.
one
inhalation plus two exhalation.
b.
one
inhalation plus one exhalation. (√)
c.
Two
inhalations plus one exhalation.
d.
one
inhalation only
8-
Which
of these animal has trachea or air tubes for exchange of gases
a.
Cockroach
(√)
b.
birds
c.
frogs
d.
lizards
9-
Which
of the following statement is true about frogs?
a.
They
have a pair of lungs
b.
They
breathe through their skin
c.
Both
a and b
d.
All
the above
Fill in the blanks with suitable words:
1-
A
cell is the smallest structural and functional unit of an organism.
2-
All
living organisms respire to get energy from food.
3-
Breathing
rate of an adult human being is 15-18 times per minute at rest.
4-
Our
breathing rate changes according to the requirement of oxygen by the
body.
5
A
|
B
|
Cutting
|
A
part of stem/branch at which leaf arises
|
Node
|
A short stem around
whihch immature overlapping leaves are folded.
|
Axil
|
A
piece of branch with a node
|
Bud
|
Point os attachment
of leaf at node.
|
Ans
A
|
B
|
Cutting
|
A
piece of branch with a node
|
Node
|
A
part of stem/branch at which leaf arises
|
Axil
|
Point os attachment
of leaf at node.
|
Bud
|
A short stem around
whihch immature overlapping leaves are folded.
|
State whether the following statements are True
or False:
1-
Cellular respiration takes place in the cells of
all organisms. (True)
2-
During
heavy exercise, the breathing rate can increase upto 25 times per minute. (True)
3-
During
breathing inhalation and exhalation take place alternately (True)
4-
Air
tubes or trachea are found in all groups of animals. (False)
5-
Give one word for the following:
(a)
The production of new individual from their
parents.
Reproduction
Reproduction
(b)
Mode of reproduction in which plants give rise
to new plants without seeds.
Asexual Reproduction
(c)
Slimy green patches found in ponds or in other
stagnetent water bodies.
Algae
(d)
The cell which results after fusion of the gamets.
Zygote
Encircle the Odd one:
1-
Nasal
cavity, lungs, ribs, kidney,
diaphragm (Organs involved in respiration)
2-
Elephant,
lion, frog, cockroach,
snake (lungs in chest cavity)
3-
Differentiate between
(a) Aerobic respiration
and anaerobic respiration
Aerobic Respiration
|
Anaerobic Respiration
|
Aerobic
respiration occurs in presence of oxygen.
|
An
aerobic respiration occurs in absence of oxygen.
|
Aerobic
respiration occurs in the mitochondria of cell.
|
Anaerobic
respiration occurs in the cytoplasm of cell.
|
It
produces high amount of energy.
|
It
produces less amount of energy.
|
In
aerobic respiration, glucose breaks down into carbon dioxide and water.
|
In
anaerobic respiration, glucose breaks down alcohol and carbon dioxide.
|
Answer the following questions:
Q. What is cellular respiration? Why is it needed?
Ans- The air we breathe in is transported to all parts of the body and ultimately to each cell. In the cells, oxygen in the air helps in the breakdown of food. The whole process of breakdown of food in the cell with the release of energy is called cellular respiration.
Q. What is cellular respiration? Why is it needed?
Ans- The air we breathe in is transported to all parts of the body and ultimately to each cell. In the cells, oxygen in the air helps in the breakdown of food. The whole process of breakdown of food in the cell with the release of energy is called cellular respiration.
Cellular
respiration is needed to release energy from food.
Q. How does anaerobic respiration takes place in our muscles during heavy exercise, fast running, heavy weight lifting or cycling?
Ans- During
heavy exercise, fast running, heavy weight lifting or cycling, the demand of
energy in the body is high, but the supply of oxygen to produce the energy is
limited. Then aerobic respiration takes place in the muscle cells to fulfill
the demand of energy.
Q. How will you prove that
the air we breathe out contains carbon dioxide?
Ans- Limewater Test-
We
will pour pour freshly prepared limewater in a test tube. Now we will blow air
with the help of a straw. The change in the appearance of limewater (it turns
cloudy) indicates that carbon dioxide is send in the air that we breathe out.
Q. Why do you sneeze? How does it help you get clean air?
Ans- We sneeze when some unwanted
particles gets past the hair in the nasal cavity and it irritates the lining of
the cavity.
Sneezing expel particles from the inhaled
air and a dust free, air enters our body.
Q. How does the movement
of ribs and diaphragm help in breathing?
Ans- Breathing involves the movement of
diaphragm and Rib cage.
1-
During
inhalation move up and outwards and diaphragm moves down. This increases space
in our chest cavity and air crashes into the lungs.
2-
During
exhalation, ribs move down and inwards, while diaphragm moves up to its former
position. This reduces the size of the chest cavity and air is pushed out of
the lungs.
Q. What is meant by
breathing? Define breathing rate.
Ans- Breathing- Breathing means
taken in air rich in oxygen and giving out air rich in carbon dioxide with the
help of respiratory organs.
Breathing
rate- The number of
times a person breathes in a minute is termed as breathing rate.
Q. Explain the breathing
mechanism in insects.
Ans-
Insects have small openings called
spiracles on the sides of their body. They have a network of tubes called
trachea for exchange of gases. Oxygen rich air rushes through spiracles into
tracheal tubes, diffuse into the body tissue and reaches every cell of the
body.
Similarly, carbon dioxide from cells
goes into the tracheal tubes and moves out through spiracles.
Q. How do fish breathe
under water?
Ans- Fish have gills, which are
feathery organs full of blood vessels.
Fish
breaths by taking water into its mouth and forcing it out through the gill
passages. As water passes through the thin walls of gills, dissolved oxygen
moves into the blood and travels to fish’s cells.
Q. Do plants also respire?
If yes, how do they respire?
They have tiny pores called stomata for
exchange of oxygen and carbon dioxide. Each part of plant can independently
take in oxygen from the air and give out carbon dioxide. Roots of plants take
up air from the air spaces present between the soil particles. plant cells use
oxygen for breakdown of glucose into carbon dioxide and water like other
organisms.
Give reason. Why?
Q. You
get muscle cramps after heavy exercises.
Ans- After
exercise, the cramps occur because during exercise our muscle cells respire
anaerobically. The partial breakdown of glucose produces lactic acid. The
accumulation of lactic acid causes muscle cramps.
Q. We
get relief from cramps after a hot water bath or massage.
Ans- Hot water bath
or massage improves circulation of blood. As a result, the supply of oxygen to
the muscle cells increases. The increase in the supply of oxygen results in the
complete breakdown of lactic acid into carbon dioxide and water.
Q.
You should cover while sneezing.
Ans- While
Sneezing, we should cover our nose so that foreign particles we expel are not
inhaled by other persons.
Q. You feel hungry after a
physical activity.
Ans- During a physical activity, a
person needs extra energy and he or she breathes faster. As a result, more
oxygen is supplied to our cells. This speeds up the breakdown of food and more
energy is released. Therefore, we feel hungry after a physical activity.
Exercises from Textbook
Q. Why does an athlete breathe
faster and deeper than usual after finishing the race?
Ans- During the race, there is need of
more energy but the supply of oxygen is limited, so anaerobic respiration takes
place in the body
After the race , an athlete breathe
faster and deeper than usual to fulfill the demand of oxygen for the complete
breakdown of lactic acid into carbon dioxide and water.
Q. List the similarities
and differences between aerobic and anaerobic respiration.
Ans- Similarities
1-
Both
are cellular respiration.
2-
Breakdown
of glucose takes place in both.
3-
Both
produce energy.
4-
Both
consume oxygen.
5-
Both
give out carbon dioxide..
Differences
Aerobic Respiration
|
Anaerobic Respiration
|
Aerobic
respiration occurs in presence of oxygen.
|
An
aerobic respiration occurs in absence of oxygen.
|
Aerobic
respiration occurs in the mitochondria of cell.
|
Anaerobic
respiration occurs in the cytoplasm of cell.
|
It
produces high amount of energy.
|
It
produces less amount of energy.
|
In
aerobic respiration, glucose breaks down into carbon dioxide and water.
|
In
anaerobic respiration, glucose breaks down alcohol and carbon dioxide.
|
Q. Why do we often sneeze
when we inhale a lot of dust Laden air?
Ans- While we inhale, some unwanted
particles such as smoke, dust, pollens etc. present in air are trapped by the
hairs present in the nasal cavity.
Sometimes, these particles get past hair
in the nasal cavity. There, they irritate the lining of nasal cavity, as a
result we sneeze to get rid of these foreign particles.
Q. Take three test tubes.
Fill three fourth of each with water. Label them A, B and C. Keep a snail in
test tube A, a water plant in test tube B and in C keep snail and plant both.
Which test tube would have the highest concentration of CO2?
Ans- Test tube A will have highest
concentration of CO2 as the snail will release carbon dioxide as a
byproduct of respiration.
Test tube B has water plant, which will
release oxygen as a byproduct of photosynthesis.
Test tube C has both a snail and a plant
of which one will release CO2 and the other will consume it.
Tick (√) the correct
answer
1-
In
cockroaches air enters the body through
a.
Lungs
b.
Gills
c.
Spiracles(√)
d.
Skin
2-
During
heavy exercise, we get cramps in the legs due to the accumulation of
a.
Carbon
dioxide
b.
Lactic
acid(√)
c.
Alcohol
d.
Water
3-
Normal
range of breathing rate per minute in an average adult person at rest is
a.
9-12
b.
15-18(√)
c.
21-24
d.
30-33
4-
During
exhalation, the ribs
a.
Move
outwards
b.
Movie
downwards (√)
c.
Move
upwards
d.
Do
not move at all
Match the items in column
1 with those in column 2
Column 1
|
Column 2
|
Yeast
|
Earthworm
|
Diaphragm
|
Gills
|
Skin
|
Alcohol
|
Leaves
|
Chest cavity
|
Fish
|
Stomata
|
Frog
|
Lungs and skin
|
Trachea
|
Ans-
Column 1
|
Column 2
|
Yeast
|
Alcohol
|
Diaphragm
|
Chest cavity
|
Skin
|
Earthworm
|
Leaves
|
Stomata
|
Fish
|
Gills
|
Frog
|
Lungs and skin
|
Cockroach
|
Trachea
|
Mark T if the statement is
true and F if it is false:
1-
During
heavy exercise, the breathing rate of a person slows down. (F)
2-
Plants
carry out photosynthesis only during the day and respiration only at night. (F)
3-
Frogs
breathe through their skin as well as their lungs. (T)
4-
The
fish have lungs for respiration. (F)
5-
The
size of the chest cavity increases during inhalation. (T)
Given below is a square of
letters in which are hidden different words related to respiration in
organisms. These words may be present in any direction - upwards, downwards, or
along the diagonals. Find the words for your respiratory system. Clues about
those words are given below the square.
1) The
air tubes of insects
2) Skeletal
structures surrounding chest cavity
3) Muscular
foot of chest cavity
4) Tiny
on the surface of the leaves
5) Small
openings on the sides of the body of an insect.
6) The
respiratory organs of human beings
7) The
openings through which we inhale
8) An
anaerobic organism
9) An organism
with tracheal system
Ans-
The mountaineers carry
oxygen with them because
a.
At
an altitude of more than 5 km there is no air
b.
The
amount of air available to a person is less than that available on the ground (√)
c.
The
temperature of air is higher than that in the ground
d.
The
pressure of air is higher than that on the ground
Extended Learning -
Activities and Projects
1 - Observe fish in an aquarium. You
find flap like structures on both sides of their heads. These are flaps, which
cover the gills. These flaps open and close alternately. On the basis of these
observations explain the process of respiration in the fish.
2- Visit a local doctor. Learn about the
harmful effects of smoking. You can also collect materials on this topic from
other sources. You can take help of your teacher or parents. Find the
percentage of people of your area who smoke. If you have a smoker in your
family, confront him with the material that you have collected.
3- Visit a doctor . Find about
artificial respiration. Ask the doctor
(a) When does a person need artificial
respiration?
(b) Does the person need to be kept on
artificial respiration temporarily or permanently?
(c)
From
where can the person get supply of oxygen for artificial respiration?
4- Measure the breathing rate of the
members of your family and some of your friends. Investigate:
(a) If the breathing rate of children is
different from that of adults.
(b) If the breathing rate of males is
different from that of females.
(c)
If
there is a difference in any of these cases try to find the reason.
Did you know?
|
For us oxygen is
essential but for those organisms, which do not use it oxygen is toxic. In
fact for humans and other organisms, it may be dangerous to breathe pure air
for long.
|
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