The DAV Class 7 Science Book Solutions Pdf and DAV Class 7 Science Chapter 7 Question Answer – Respiration in Organisms are essential study tools for DAV public school students in Class 7.
DAV Class 7 Science Ch 7 Question Answer – Respiration in Organisms
DAV Class 7 Science Ch 7 Solutions – Respiration in Organisms
Something To Know
A. Fill in the blanks.
Question 1.
Lactic acid is produced during ________ respiration.
Answer:
Anaerobic
Question 2.
Insects have organs, called ________ for respiration.
Answer:
Trachea
Question 3.
Taking in of air, rich in oxygen, is called ________
Answer:
Inspiration.
Question 4.
An adult human being normally breathes from ________ to ________ times per minute.
Answer:
14 to 20
Question 5.
The movement of lungs is controlled by the ________ and the ________
Answer:
Rib cage, Diaphragm
Question 6.
________ acts as the respiratory carrier in our body.
Answer:
Haemoglobin
B. Match the following:
| 1. Lactic acid | c | Transpiration |
| 2. Stomata | a | Pores on branches |
| 3. Respiratoiy carrier | e | Muscle cramps |
| 4. Lenticels | b | Fermentation of yeast |
| 5. Alcohol | d | Haemoglobin |
C. Tick (✓) the correct option.
1. Respiration helps in
(a) locomotion
(b) digestion
(c) absorption
(d) obtaining energy
Answer:
(d) Obtaining energy
2. Stomata performs the function of
(a) absorption of water
(b) absorption of minerals
(c) exchange of gases
(d) movement of food
Answer:
(c) Exchange of gases
3. The process represented by the following equation,
(glucose + oxygen → Carbon dioxide + water + energy)
(a) Is photosynthesis
(b) Is transpiration
(c) Is fermentation
(d) Is aerobic respiration
Answer:
(d) Is aerobic respiration
4. To survive, plant roots need
(a) carbon dioxide
(b) oxygen
(c) chlorophyll
(d) sunlight
Answer:
(b) Oxygen
5. Earthworms and leeches respire through their
(a) lungs
(b) gills
(c) trachea
(d) skin
Answer:
(d) Skin.
D. Answer the following questions in brief.
Question 1.
Define respiration. Name the two types of respiration.
Answer:
The process of oxidizing the food to produce energy by a living being is called respiration. Two types of respiration are; aerobic respiration and anaerobic respiration.
Question 2.
Name the respiratory organ of the following:
(a) crab,
(b) man,
(c) leech,
(d) an insect
Answer:
(a) Crab → gills,
(b) Man → Lungs,
(c) Leech → Skin,
(d) an insect → Tracheae
Question 3.
Define transpiration.
Answer:
Loss of water vapour through stomata and lenticels in plants is called transpiration.
Question 4.
Define the term ‘breathing rate’.
Answer:
The number of breathings per minute is called breathing rate.
Question 5.
Name the body organs which help lungs during the process of breathing.
Answer:
Diaphragm and ribs
Question 6.
Why do we need to breathe out carbon dioxide?
Answer:
Carbon dioxide is a harmful gas. It can prove lethal if it accumulates in the body. Hence, we need to breathe out carbon dioxide.
E. Answer the following questions.
Question 1.
Why do we get muscle cramps after heavy exercise?
Answer:
Anaerobic respiration also happens in our muscles, when there is extra demand of energy by the muscle cells. When we do heavy exercise, our muscles need more energy. Anaerobic respiration happens in the muscle cells to provide extra energy. As a result of this, lactic acid is released in muscles. Due to lactic acid, we get muscle cramps.
Question 2.
Why does a potted plant die when over watered?
Answer:
When a plant is overwatered, it needs to get rid of excess water through transpiration. But the rate of transpiration may not be able to remove excess water. Due to this, an overwatered plant usually dies.
Question 3.
Where are stomata found in a plant? State their function.
Answer:
Stomata are present on the surface of leaves. Exchange of gases happens through stomata.
Question 4.
How is oxygen transported from lungs to the other parts of the body?
Answer:
Oxygen from lungs enters the blood through walls of alveoli. After that, haemoglobin carries oxygen to different organs of the body.
Question 5.
Draw a neat, well-labelled diagram of the human respiratory system.
Answer:
Question 6.
Describe an activity to show that exhaled air contains carbon dioxide.
Answer:
For this, take a test tube and fill it with freshly prepared lime water. Take a drinking straw in your mouth and blow air through this in lime water. You will notice that the lime water turns milky. This happens because of carbon dioxide. This shows that exhaled air contains carbon dioxide.
Question 7.
Describe the changes that take place (i) around the rib cage (u) diaphragm (iii) chest cavity, during inspiration. State the effect of these changes.
Answer:
The rib cage is lifted upwards, the diaphragm is lowered and the chest cavity expands. With these changes, lungs also expand. Expansion of lungs results in air moving inside the lungs.
Value Based Question
It was time for the 400 m race in the annual athletic meet of the school. Shweta, who was tipped to win the race, maintained a clear lead over others till about 30 m from the finishing line. She then felt cramps in her legs but did not give up. She quickly took some deep and fast breaths and continued running. Her presence of mind, determination, courage and positive attitude, helped her to just manage to win the race. Rita and Neetu, who finished second and third, respectively, were the first to congratulate her on her success.
Question 1.
State the values displayed by Shweta.
Answer:
Determination, courage, presence of mind and a hunger to excel.
Question 2.
Write about ‘some situation in which you, or one of your friends, displayed a behaviour similar to that of Rita and Neetu.
Answer: It was a singing competition in our school. Ankit is a very good singer. But he came second in the competition because Rohan proved to be a better singer on that day. But Ankit was unfazed. He moved to the stage and congratulated Rohan for winning the first prize.
Question 3.
State the likely reason due to which Shweta felt cramps in her legs,
Answer:
Shweta was running too fast. Her leg muscles needed more energy. For this, anaerobic respiration began in her leg muscles. This resulted in accumulation of lactic acid in her leg muscles. This caused cramps in her legs.
Something To Do
Question 1.
Observe the changes in a leaf when both of its surfaces are coated with. oil/Vaseline. Perform this activity and give a simple explanation of your observation.
Ans, If both the surfaces of a leaf are coated with oil or Vaseline, the exchange of gases through the leaf would stop. The cells of the leaf will not be in a position to carry out respiration. Due to this, the leaf would finally die.
Question 2.
Find out about two diseases related to the respiratory system. List their causes, their effect on respiration and their cure.
Answer:
Asthma and pneumonia are two examples of diseases of the respiratory system. Asthma can happen because of genetic causes and also because of allergic reactions. Asthma can be managed with the help of some medicines and inhaler. Pneumonia happens because of bacterial infections. Antibiotics are given to treat pneumonia.
Question 3.
Record the breathing rates, of your friends and their family members (i) when at rest and (ii) after performing the activities given in the following table. Let the person rest for 15 minutes after performing each activity. Enter your results in the table given below:
| Name of the person | At rest | After brisk walk for 10 minutes | After skipping 100 times |
Answer:
Do it yourself.
DAV Class 7 Science Chapter 7 Solutions – Respiration in Organisms
I. Fill in the blanks.
Question 1.
________ is broken down during respiration.
Answer:
Glucose
Question 2.
Glucose is formed during ________
Answer:
Respiration.
Question 3.
________ is formed in muscle cells as a result of anaerobic respiration.
Answer:
Lactic
Question 4.
In fishes, exchange of gases takes place in ________
Answer:
Question 5.
Stomata open during ________ only.
Answer:
Gills
Question 6.
The red pigment which is present in human blood is called ________
Answer:
Haemoglobin
II. Tick (✓) the correct option.
1. Which of these parts of the human respiratory system is also called the voice box?
(a) Phaiynx
(b) Larynx
(c) Trachea
(d) Alveoli
Answer:
(b) Larynx
2. Which is the respiratory organ in cockroaches?
(a) Gills
(b) Lungs
(c) Stomata
(d) Trachea
Answer:
(d) Trachea
3. Which is the respiratory organ in prawns?
(a) Gills
(b) Lungs
(c) Stomata
Answer:
(a) Gills
4. Stomata are present in which plant part?
(a) Roots
(b) Stem
(c) Leaves
(d) Trachea
Answer:
(c) Leaves
5. How many lungs are there in birds?
(a) One
(b) Two
(c) Three
(d) Four
Answer:
(b) Two
6. Apart from carbon dioxide, which substance is formed respiration?
(a) Oxygen
(b) Hydrogen
(c) Water
(d) Alcohol
Answer:
(c) Water
III. Answer the following questions in brief.
Question 1.
Name the fuel used for the production of energy during respiration in our body.
Answer:
Glucose is the fuel used for the production of energy during respiration in our body.
Question 2.
Name the respiratory organs of the following:
(a) Frog
Answer:
Lungs (on land) and skin (in water)
(b) Man
Answer:
Lungs
(c) Earthworm
Answer:
Skin
(d) Leech
Answer:
Skin
Question 3.
Describe the mechanism of breathing in our body.
Answer:
Mechanism of Breathing: The process of breathing is divided into two phases, viz. inspiration and expiration.
Inspiration: During inspiration, the muscles around the rib cage contract and lift the ribs upward and outward. This lowers the diaphragm. As a result of these changes, the chest cavity expands and with that the lungs also expand. With the expansion of lungs, air moves inside the lungs.
Expiration: During expiration, the muscles around the rib cage expand and rib cage is lowered. This pushes the diaphragm up. As a result of these changes, the chest cavity contracts and with that the lungs also contract. With the contraction of lungs, air moves outside the lungs.
IV. Answer the following questions.
Question 1.
What do you understand by respiration?
Answer:
The process in which organisms convert sugars into biochemical energy by using oxygen. At the end of respiration, energy is produced which is utilized to earnout various life processes. Additionally, carbon dioxide is released at the end of respiration.
Question 2.
What are the two main parts in respiration?
Answer:
Respiration happens in two main parts:
- Exchange of gases: Organisms follow different methods for exchange of gases. Oxygen enters an organism and carbon dioxide comes out.
- Cellular respiration: In this step, oxygen is utilized by cells to breakdown sugars so that energy can be released.
Question 3.
What do you understand by aerobic respiration?
Answer:
Aerobic Respiration: This type of respiration takes place in the presence of oxygen. Plants and animals use this method of respiration.
Question 4.
What do you understand by anaerobic respiration?
Answer:
Anaerobic Respiration: This type of respiration takes place in the absence of oxygen. Anaerobes are the organisms which use this method of respiration. Such organisms do not require oxygen to produce energy. Fungi and some of the bacteria use this method of respiration.
Question 5.
Give a brief explanation of respiration in plants.
Answer:
Plants also respire to release energy. Plants take in oxygen through minute pores on the surface of roots, stems and leaves. The pores on the leaves are called stomata. Oxygen enters through these stomata and carbon dioxide comes out during respiration. The oxygen goes to different cells where it is utilised to breakdown glucose. The process of respiration can be written as following equation.
Glucose + Oxygen → Carbon dioxide + Water + Energy
V. State whether the following statements are true or false.
1. Respiration is a type of combustion of food at ordinary temperature.
2. Breathing is a process that takes place at the cellular level.
3. Oxygen is released during the process of anaerobic respiration.
4. Sugar is a substrate for respiration.
5. Fishes use tracheae for respiration.
Answer:
- Respiration is a type of combustion of food at ordinary temperature. (True)
- Breathing is a process that takes place at the cellular level. (False)
- Oxygen is released during the process of anaerobic respiration. (False)
- Sugar is a substrate for respiration. (True)
- Fishes use tracheae for respiration. (False)
VI. Match the following:
| Column A | Column B |
| 1. Diaphragm | (a) Anaerobic respiration |
| 2. Stomata | (b) Respiration |
| 3. Trachea | (c) Below lungs |
| 4. Alcohol | (d) Insect |
| 5. Energy | (e) Leaf |
Answer:
| Column A | Column B | |
| 1. Diaphragm | c | (a) Anaerobic respiration |
| 2. Stomata | e | (b) Respiration |
| 3. Trachea | d | (c) Below lungs |
| 4. Alcohol | a | (d) Insect |
| 5. Energy | b | (e) Leaf |
VII. Differentiate between:
Question 1.
Aerobic respiration and anaerobic respiration
Answer:
| Aerobic respiration | Anaerobic respiration |
| Happens in the presence of oxygen. | Happens in the absence of oxygen. |
| Carbon dioxide is released in the end. | Alcohol or lactic acid is released in the end. |
| Examples of organisms: Man, plants, frog, etc. | Examples of organisms: Yeast, some bacteria |
Question 2.
Inhalation and exhalation
Answer:
The process of taking in oxygen rich air is called inhalation, while the process of giving out carbon dioxide rich air is called exhalation.
Question 3.
Stomata and gills
| Stomata | Gills |
| Present on the leaves of plants. | Present in fish, prawn, crabs, etc. |
| Carbon dioxide also goes in through stomata. | Carbon dioxide never goes in. |
| Transpiration is another important function. | No such function is present. |
Question 4.
Respiration and photosynthesis
Answer:
| Respiration | Photosynthesis |
| Happens in all organisms | Happens in green plants only |
| Glucose is broken down | Glucose is formed |
| Energy is released | Energy is consumed |
| Carbon dioxide is released | Carbon dioxide is consumed |
| Oxygen is consumed | Oxygen is released |
Question 5.
Breathing rate in man and rat
Answer:
A human being breathes about 14 to 20 times per minute, while a rat breathes about 60 times per minute.
VIII. Projects
Question 1.
Take a bottle with wide mouth, some drinking straws and balloons. With the help of these things, make a model to show breathing mechanism in huma
Answer:
Do it yourself.
Question 2.
Devise an experiment to show that respiring organisms produce heat energy.
Answer:
Do it yourself.
Question 3.
With the help of a flow chart, show various types of respiration.
Answer:
Do it yourself.
Question 4.
Try to observe your breathing pattern when you speak. Do you inhale or exhale while speaking. What could be the reason for this? You will find it interesting when you explore the function of a structure called larynx in this regard.
Answer:
When we speak, we breathe out. Speaking involves the use of voice box or larynx. When air is forced out through the voice box, it creates vibrations in the vocal cords and we are able to speak.