Living Science Biology Class 7 ICSE Solutions Chapter 7 Respiration in Animals and Plants

ICSE Living Science Biology for Class 7 Solutions Chapter 7 Respiration in Animals and Plants

Check Your Progress

Answer these questions.

Question 1.
What is external respiration ?
Answer:
External respiration or breathing is a mechanical or physical process that involves inhaling (breathing in) air rich in oxygen and exhaling (breathing out) air rich in carbon dioxide.

Question 2.
Write the equation showing the process of respiration.
Answer:

Question 3.
In what form is the energy released during respiration stored ?
Answer:
The energy released is stored in the form of an energy-rich chemical substance called ATP (Adenosine triphosphate).

Question 4.
Name the two types of respiration.
Answer:
Aerobic respiration and anaerobic respiration.

Question 5.
Name the organ of respiration in Ashes.
Answer:
Gills

Question 6.
What are the holes on the sides of the body of insects called ?
Answer:
Spiracles

Check Your Progress

Answer the following in one word.

Question 1.
What is the muscular sheet below the lungs called ?
Answer:
Diaphragm

Question 2.
Which organ is called the voice box ?
Answer:
Larynx

Question 3.
Which membrane covers the lungs ?
Answer:
Pleural membrane

Question 4.
Where does exchange of gases takes place ?
Answer:
Lungs (alveoli)

Question 5.
What is formed when oxygen combines with haemoglobin ?
Answer:
Oxyhaemoglobin

Question 6.
What is carbaminohemoglobin ?
Answer:
Carbon-dioxide combines with haemoglobin to form carbominohaemoglobin.

A. Tick the most appropriate answer.

Question 1.
The products of respiration are :
a. carbon dioxide and oxygen
b. oxygen and energy
c. carbon dioxide, water and energy & carbon dioxide, oxygen and energy.
Answer:
c. carbon dioxide, water and energy

Question 2.
Glucose is oxidized to produce ethyl alcohol during
a. excretion
b. aerobic respiration
c. anaerobic respiration
d. photosynthesis
Answer:
c. anaerobic respiration

Question 3.
In insects like grasshopper, there is a well-developed system of air tubes called
a. tracheae
b. gills
c. lungs
d. alveoli
Answer:
c. lungs

Question 4.
Frogs breathe through the –
a. moist skin
b. lungs
c. mouth cavity
d. all of these
Answer:
d. all of these

Question 5.
Inside the chest, the trachea divides into two branches called
a. bronchi
b. bronchioles
c. bronchus
d. alveolus
Answer:
a. bronchi

Question 6.
In humans beings, during inhalation the diaphragm.
a. moves up
b. moves down
c. remains at its position
d. moves up and moves down
Answer:
b. moves down

Question 7.
Exhaled air contains –
a. amore carbon dioxide
b. more oxygen
c. more nitrogen
d. more hydrozen
Answer:
a. more carbon dioxide

Question 8.
Plants have these for exchange of gases.
a. spiracles and stomata
b. lenticels and spiracles
c. lenticels and stomata
d. buds and flowers
Answer:
c. lenticels and stomata

B. Fill in the blanks.

Question 1.
The two types of respiration are ………. and …………..
Answer:
The two respiration of respiration are aerobic and anaerobic.

Question 2.
Muscles of human beings switch to …………. respiration in the absence of oxygen.
Answer:
Muscles of human beings switch to anaerobic respiration in the absence of oxygen.

Question 3.
carbon dioxide, water and energy …………..
Answer:
In aerobic respiration, food is completely oxidized into carbon dioxide, water and energy.

Question 4.
Below the lungs is a muscular sheet called …………..
Answer:
Below the lungs is a muscular sheet called diaphragm.

Question 5.
Bronchi divide into smaller tubes called ………….
Answer:
Bronchi divide into smaller tubes called bronchioles.

Question 6.
In human beings, exchange of gases takes place in ………….
Answer:
In human beings, exchange of gases takes place in alveoli (lungs).

C. State if the following statements are true or false. Correct the statement if it is false.

Question 1.
The oxidation of food to release energy and water is called breathing.
Answer:
False. The oxidation of food to release energy and water is called Respiration.

Question 2.
Anaerobic respiration takes place in our bones.
Answer:
False. Anaerobic respiration takes place in our muscles.

Question 3.
The microscopic air sacs present in the lungs are called bronchi
Answer:
False. The microscopic air sacs present in the lungs are called alveolar sacs.

Question 4.
Respiration that takes place through skin is called pulmonary respiration.
Answer:
False. Respiration that takes place through skin is called cutaneous respiration:

Question 5.
Stomata are present on mature roots and woody stems.
Answer:
False. Lenticels are present on mature roots and woody stems.

Question 6.
In photosynthesis oxygen is released as a by-product.

Column A(Organism)	Column B(Organ of Respiration)
1. fish	a. lungs
2. human beings	b. tracheae
3. frog	C. gills
4. cockroach	d. moist skin, mouth cavity and lungs
5. bird	e. lungs

Answer:

Column A(Organism)	Column B(Organ of Respiration)
1. fish	C. gills
2. human beings	a. lungs
3. frog	d. moist skin, mouth cavity and lungs
4. cockroach	b. tracheae
5. bird	e. lungs

E. Differentiate between

Question 1.
aerobic respiration and anaerobic respiration.
Answer:
Aerobic Respiration

• It takes place in the presence of oxygen.
• Complete oxidation of food takes place.
• 38 molecules of ATP are produced by oxidation of one gram mole of glucose.
• CO₂ and H₂O are the end products.

Anaerobic Respiration :

• It takes place in the absence of oxygen.
• Incomplete oxidation of food takes place.
• 2 molecules of ATP are produced by oxidation of gram mole of glucose.
• Ethyl alcohol (C₂H₅OH) and CO₂ are the end products.

Question 2.
external and internal respiration
Answer:
External repiration

• It is the mechanical process of inhaling and exhaling air. It does not involve any enzymes.
• It involves taking in oxygen and giving out carbon dioxide.
• No energy is released.
• It takes place outside the cell.

Internal respiration :

• It is a complex biochemical process in which enzymes are involved.
• It involves the oxidation of glucose into carbon dioxide, water and energy.
• Energy is released and stored in the form of ATP.
• It takes place inside the cell.

Question 3.
tracheae and tracheoles
Answer:
Tracheae :

• It is a system of air tubes in insects by which air is diffused into body cells.
• It receive air through external openings called spiracles on insects body.
• They are less closely associated with the tissue cells.

Tracheoles:

• Tracheae are further divided into finer tubes called tracheoles in insects.
• It receives air through tracheae.
• They are more closely associated with the cells and tissues in the transfer of oxygen.
  
  

Question 4.
bronchi and alveoli.
Answer:
Bronchi

• The two branching tube of trachea are called bronchi.
• There are two bronchi
• The walls of bronchi are not richly supplied with blood capillaries.

Alveoli :

• The out growths of microscopic air sacs are called alveoli.
• There are millions of alveolar sacs.
• The walls of the bronchioles are richly supplied with blood capillaries.

Question 5.
photosynthesis and respiration.
Answer:
Photosynthesis

• It is an anabolic process.
• It takes place in the presence of sunlight
• Oxygen is released as the by product.
• It takes place in the green parts of the plant that is green leaves, young green stems.
• Food is synthesised by plants using CO, and HjO

Respiration :

• It is a catabolic process Sunlight is not necessary for the respiration Carbondioxide is released as the by product.
• It takes place in all the parts of a plant.
• Food is oxidized using oxygen to release energy

F. Answer the following in short

Question 1.
Define respiration.
Answer;
The process of conversion of glucose molecules in food into energy rich molecules, carbondioxide and water with the help of oxygen is known as respiration.

Question 2.
What is the full form of ATP ?
Answer:
ATP is the energy currency of cell. Its full form is Adenosine Triphosphate.

Question 3.
What is respiratory tract ?
Answer:
The path through which the air travels to the lungs and back to the atmosphere in humans is called the respiratory tract.

Question 4.
Define cutaneous respiration ?
Answer:
The exchange of gases through moist skin and blood capillaries underneath is called cutaneous respiration.e.g. in frogs.

Question 5.
What is the function of pleural fluid ?
Answer:
Pleural fluid keeps the surface of the lungs moist for easy diffusion of gases (oxygen and carbon dioxide). ,

Question 6.
What is the role of the diaphragm in breathing mechanism ?
Answer:
Diaphragm moves up and down and helps in the exchange of air between the atmosphere and lungs. :

G. Answer the following in detail.

Question 1.
How is the process of cellular respiration different from breathing ?
Answer:
Respiration :

• It is a complex bio – chemical process which involves enzymes.
• It involves oxidation of glucose in to CO₂, waterand energy.
• Energy is released and stored in the form of ATP.
• It takes place inside the cell.

Breathing :

• It is a mechanical process without the involvement of enzymes.
• It involves only the exchange of oxygen and CO₂
• No energy is released.
• It takes place outsidethe cell.

Question 2.
Explain the process of Cellular Respiration.
Answer:
Cellular Respiration is a biochemical process which involves the oxidation of glucose to release energy, carbondioxide and water are released as by – products.

It involves a series of chemical reactions controlled by different enzymes. The energy released in the process is stored in the form of energy rich substance called ATP (Adenosine triphosphate). The ATP molecules are stored in the cells and later on can be broken down to release energy for various metabolic activities. The entire process takes place partially in the cytoplasm and partially in the mitochondria of our body cells. The process of conversion of glucose molecules in food in to energy rich molecules, CO₂ and water with the help of oxygen is known as respiration.

Question 3.
How does gaseous exchange take place in frogs ?
Answer:
Amphiiians like adult frogs can breathe through their moist skin, lungs and mouth cavity. When a frog is in water, oxygen enters through the skin and passes into blood capillaries underneath the skin. This exchange of gases through the skin is called cutaneous respiration. On land, adult frogs breathe through their mouth cavity and lungs. Lungs are small balloon-like organs into which oxygen-rich air is forced through mouth cavity and the nostrils. Oxygen is absorbed from the air by the lining of the mouth and lungs and carbon dioxide is given out. Tadpoles live in water and hence breathe through their gills until they grow into adult frogs.

Question 4.
How and where is the blood enriched with oxygen in human beings ?
Answer:
In human beings, blood is enriched with oxygen in alveoli where exchange of gases takes place by diffusion.
The inhaled air, which is rich in oxygen reaches alveoli after passing through trachea, bronchi and bronchioles. It contains very little carbon dioxide. The blood capillaries surrounding the alveoli, on the other hand, contain blood

that has more carbon dioxide and less oxygen. Thus, oxygen diffuses through the thin walls of the capillaries into the blood and combines with haemoglobin in the red blood cells (RBCs) and forms oxyhaemoglobin. The blood enriched with oxygen is then carried to all the cells of the body.

Question 5.
In human beings, what happens to oxygen after it is inhaled through the nose ?
Answer:
Air rich in oxygen, enters the body through the nostrils (nose). From the nose, air enters the pharynx which leads to larynx and then trachea (windpipe). From trachea, it enters the bronchi and enters the lungs. From bronchi, it enters bronchioles and finally the alveoli. The oxygen diffuses through the thin walls of blood capillaries (surrounding) into the blood and combines with haemoglobin to form oxyhaemoglobin. Tire oxygen in blood is canied to all body cells where internal respiration takes place in a series of chemical reactions and food (in the form of glucose) is converted into carbon-dioxide water and energy in the fonn of ATP, using the oxygen.

Question 6.
With the help of labelled diagrams show the mechanism of breathing in human beings.
Answer:
The process of taking in oxygen and giving out carbondioxide is called breathing. It is a physical process and carried out by the movement of the various body parts. Inhalation : When we inhale air our ribs move upwards and outwards and the diaphragm moves downwards. The volume of chest cavity increases and the air pressure is reduced, as a result of which air flows in to the lungs. Exhalation : When we exhale air, that is breathe out air, the diaphragm moves upwards and the ribs move downwards and inwards. The space inside the chest cavity decreases and the air pressure is increased as, a result the air rushes out.

Question 7.
Explain the process of exchange of gases in plants.
Answer:
In plants, exchange of gases takes place through stomata and lenticels.
(i) Stomata – They are tiny pores present on the lower surface of leaves and young green stems. The gaseous exchange takes place in plants mostly through stomata. They remain open during the day and close at night.
(ii) Lenticels – In certain trees, the mature roots and woody stems have tiny openings called lenticels which enable the oxygen to reach the intercellular spaces of interior tissues and carbon dioxide to be released into the atmosphere. The exchange of gases (oxygen and carbon dioxide) in plants takes place by two processes – photosynthesis and respiration.

(i) Photosynthesis occurs during the day. It takes in carbon dioxide and gives out oxygen. A part of oxygen formed is used by plants for respiration and rest is given out through •stomata.
(ii) Respiration occurs throughout day and night. Oxygen is used and carbon dioxide is given out. This carbon dioxide is used by the plant for photosynthesis during the day. At night, in the absence of photosynthesis, carbon dioxide is released into the air through stomata.

H. Number the following organs in the correct order to show the path taken by fresh air at the time of inhalation.
trachea, nose, bronchioles, bronchi, larynx, alveoli, pharynx, lungs
Answer:
nose → pharynx → larynx → trachea → bronchi → lungs → bronchioles → alveoli.

I. Look at the picture given below and answer the following questions.

Question 1.
Identify the organ show n in the diagram. Describe its role.
Answer:
The organ is lung within which a bronchiole ends into alveolar sacs containing alveoli. The exchange of gases takes place between alveoli and blood capillaries by diffusion in lungs.

Question 2.
Name the parts labelled a – d and state their functions.

Answer:
a → Bronchiole
b → Blood capillaries
c → Alveoli
d → Alveolar sac

Living Science Biology Class 7 ICSE Solutions