Chapter 10- Respiration in Organisms–Class 7 Science – Question and Answer (Long Answer)

Chapter 10- Respiration in Organisms -Long Questions and Answers (Solved Worksheet)

Question- Differentiate between aerobic and anaerobic respiration. 

Answer-

Criteria	Aerobic Respiration	Anaerobic Respiration
Definition	A process where glucose is broken down using oxygen to produce carbon dioxide, water, and energy.	A process where glucose is broken down without the use of oxygen.
Location	Occurs in the cells of organisms (cellular respiration).	Also occurs at the cellular level.
Oxygen Requirement	Requires oxygen.	Does not require oxygen.
End Products	Produces carbon dioxide and water as the main by-products.	By-products vary; in humans, lactic acid is commonly produced during heavy exercise.
Energy Production	Produces a significant amount of energy.	Produces less energy compared to aerobic respiration.
Occurrence in Humans	Common during normal activities when oxygen supply is adequate.	Occurs during heavy exercise when oxygen supply to muscle cells is insufficient.

Question- Explain the relationship between physical activities and respiration. 

Answer- Physical activities and respiration are intrinsically linked. During physical activities such as exercise, the body’s demand for oxygen increases to produce more energy required for the muscles to work efficiently. This need is met by an increase in the breathing rate, ensuring that more oxygen is inhaled and transported to the muscle cells where it is utilised for cellular respiration to produce energy.

• Increase in Breathing Rate- Physical activities necessitate an elevated breathing rate. The increased frequency of breathing ensures that a higher amount of oxygen is available for the process of cellular respiration to generate the required energy.
• Depth of Breaths- During physical activities, the depth of breaths also augments. This allows for a more significant volume of air, enriched with oxygen, to be inhaled, facilitating enhanced oxygen availability for the muscles involved in the activity.
• Anaerobic Respiration- In cases of intense physical activities, when the supply of oxygen to the muscle cells is not adequate, anaerobic respiration may occur. This form of respiration allows muscles to temporarily produce energy without the immediate need for oxygen, resulting in the creation of lactic acid.
• Adaptability- The human body is adept at adjusting its respiratory rate based on the intensity of physical activity. This adaptation helps in efficiently meeting the increased oxygen demands of the body, ensuring that the muscles receive an adequate supply to maintain activity.
• Variation in Respiratory Organs- Different organisms exhibit variations in their respiratory organs, which operate similarly in response to physical activity, adapting to ensure that oxygen needs are met to sustain the increased energy demands.

Also Check -Rapid Revision – Class 7 Science- Chapter 10- Respiration in Organisms

Question- Explain how anaerobic respiration in muscles is related to muscle cramps. 

Answer-Anaerobic respiration occurs in the muscles when they are subjected to intense physical activity and the supply of oxygen is insufficient to meet the increased energy demands. In such conditions, the muscles shift from aerobic respiration (which uses oxygen) to anaerobic respiration (which doesn’t rely on oxygen) to continue producing energy.

• Lactic Acid Production- The primary difference between aerobic and anaerobic respiration is the end product. In anaerobic respiration in muscles, glucose is broken down into lactic acid. This production of lactic acid is a quick way for the muscles to generate energy without oxygen.
• Accumulation of Lactic Acid- When the physical activity is intense and prolonged, lactic acid starts to accumulate in the muscle cells because it is produced at a faster rate than it can be removed or metabolised.
• Muscle Cramps- The build-up of lactic acid in the muscles reduces the pH within the muscle cells, making the environment more acidic. This altered pH can interfere with the ability of the muscles to contract and relax properly. This disruption can lead to muscle cramps, which are sudden, involuntary, and often painful muscle contractions.
• Relief through Oxygen- After the intense activity stops and the muscles receive a more regular supply of oxygen, the accumulated lactic acid is gradually converted back to glucose or sent to the liver to be converted to pyruvate, thereby relieving the cramps.

Also Check – NCERT Exemplar Solutions- Class 7 Science Chapter 6- Respiration in Organisms.

Question- Discuss the variability in breathing rates based on activity levels and its correlation with the body’s energy needs. 

Answer- Breathing rates vary significantly based on the level of physical activity, primarily due to the body’s fluctuating energy demands. At rest, an average adult breathes about 15-18 times per minute. This breathing rate suffices to maintain the necessary oxygen and carbon dioxide levels in the body, ensuring that all cells receive the required oxygen for cellular processes.

• Resting Breathing Rate- At rest, the breathing rate is paced to meet the body’s basic energy requirements. The oxygen inhaled is utilised for cellular activities essential for the survival and maintenance of the body’s functions.
• Breathing Rate During Exercise- During exercise, the body’s energy needs increase, requiring a higher intake of oxygen for enhanced cellular respiration. Consequently, the breathing rate can surge up to 25 times per minute or more, to meet the heightened oxygen demands.
• Depth of Breaths- With increased physical activity, the depth of each breath also increases. This ensures that a more substantial volume of oxygen is available for the body’s cells, meeting the escalated energy needs during physical exertion.
• Adaptability to Energy Needs- The body’s respiratory system is highly adaptable and automatically adjusts its rate of breathing based on the energy needs at any given moment. Enhanced physical activity necessitates a greater energy output, hence the breathing rate, and depth naturally increase.
• Anaerobic Respiration during High-Intensity Activities- In situations of intense physical activities where oxygen supply is limited, the body may resort to anaerobic respiration to fulfil its immediate energy needs, even though this is less efficient compared to aerobic respiration.

Question- Explain the pathway of inhaled air in the breathing process. 

Answer-Inhalation- The breathing process begins with the inhalation of air through the nostrils. The nasal cavity, lined with fine hairs and mucus, traps any dust or foreign particles present in the inhaled air.

• Travelling through the Pharynx and Larynx- The filtered air then passes through the pharynx, a common passage for both food and air, and then moves through the larynx, which is the voice box.
• Entering the Trachea- From the larynx, the air travels down the trachea. The trachea is a tube that extends from the neck to the chest, ensuring that air reaches the lungs.
• Passing through the Bronchi- The trachea divides into two bronchi, each leading to a lung. The bronchi further subdivide into smaller tubes, distributing the air uniformly throughout the lungs.
• Reaching the Alveoli- The smallest tubes end in tiny air sacs known as alveoli. It is here that the exchange of oxygen and carbon dioxide takes place. Oxygen from the inhaled air passes through the thin walls of the alveoli and is absorbed by the blood in the capillaries, while carbon dioxide is expelled from the blood into the alveoli to be exhaled out of the body.

Question- How can practical activities, like measuring chest expansion, enhance the understanding of the breathing mechanism? 

Answer- Practical activities like measuring chest expansion allow for a hands-on understanding of the breathing mechanism, enabling visualisation of the lungs’ and chest’s expansion and contraction. This experiential learning provides insight into the volume of air the lungs can hold and the flexibility of chest and lung tissues, enhancing the comprehension of the breathing process’s physiological aspects.

Question- Can you explain the significance of using balloons and a rubber sheet in visually demonstrating the breathing mechanism? 

Answer- In the model, balloons represent the lungs, and the rubber sheet represents the diaphragm. Pulling down the rubber sheet simulates the contraction of the diaphragm during inhalation, causing the balloons (lungs) to inflate. Pushing the rubber sheet up simulates the relaxation of the diaphragm during exhalation, causing the balloons (lungs) to deflate. This visually demonstrates the breathing mechanism, aiding in understanding the roles of the lungs and diaphragm in breathing.

Question- What does the mirror test demonstrate in the experiment focused on understanding exhaled air? 

Answer- The mirror test demonstrates the presence of water vapour in the exhaled air. When one exhales onto a mirror, a film of moisture or condensation appears, indicating that the exhaled air contains water vapour.

Question- Can you explain how the composition of exhaled air differs from inhaled air and why? 

Answer– The composition of inhaled and exhaled air differs primarily in the concentrations of oxygen (O2) and carbon dioxide (CO2). These differences arise due to the process of cellular respiration that occurs within our body.

Inhaled Air-

• Oxygen (O2)- Approximately 21%
• Carbon Dioxide (CO2)- Roughly 0.04%

Exhaled Air-

• Oxygen (O2)- Drops to around 16.4%
• Carbon Dioxide (CO2)- Increases to about 4.4%

Reason for the Difference-

• Cellular Respiration- When we inhale, oxygen is used by cells for the process of cellular respiration, where glucose is broken down to release energy. In this process, oxygen is consumed, and carbon dioxide is produced as a waste product.
• Oxygen Utilisation- The decrease in the oxygen percentage in exhaled air (from 21% to 16.4%) signifies that a portion of the inhaled oxygen is used by our cells for energy production.
• Carbon Dioxide Production- The increase in the carbon dioxide percentage in exhaled air (from 0.04% to 4.4%) indicates the removal of the CO2 produced during cellular respiration.

Question- How is the breathing mechanism of insects different from that of mammals? Answer- Comparison of Breathing Mechanisms

Feature	Insects	Mammals (e.g., Humans)
Respiratory Organ	Tracheae	Lungs
Air Entry and Exit	Spiracles	Nose/Mouth to Trachea
Gas Exchange Location	Directly at tissues through tracheae	In the lungs
Blood Involvement	No involvement of blood in direct gas exchange	Blood transports gases between the lungs and tissues

Explanation of Differences-

• Respiratory Organ-
  • Insects- Utilise a network of tubes known as tracheae for respiration.
  • Mammals- Use lungs for breathing and respiration.
• Air Entry and Exit-
  • Insects- Have spiracles which are tiny openings that allow air to enter and exit.
  • Mammals- Breathe in air through the nose or mouth which then travels to the lungs via the trachea.
• Gas Exchange Location-
  • Insects- The exchange of gases occurs directly at the tissues through the tracheae.
  • Mammals- The gas exchange takes place in the lungs, and oxygen and carbon dioxide are transported via the bloodstream.
• Blood Involvement-
  • Insects- The blood does not play a direct role in transporting gases for respiration.
  • Mammals- Blood is instrumental in carrying oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs for exhalation.

Question- How do gills function in the respiratory process of fish? 

Answer- Functioning of Gills in Fish Respiration-

Fish rely on gills to obtain the oxygen they need for respiration. Here’s how the process works-

• Water Intake- Fish take in water, containing dissolved oxygen, through their mouths.
• Passage over Gills- The water flows over the gills, which are specialised respiratory organs located on either side of the fish’s head.
• Oxygen Absorption- Gills have thin, flat filaments that are rich in blood vessels. As water passes over these filaments, oxygen from the water diffuses directly into the fish’s bloodstream.
• Carbon Dioxide Excretion- At the same time, carbon dioxide, a waste product from the fish’s body, diffuses from the blood into the water through these gill filaments. This is how fish get rid of the carbon dioxide produced during cellular respiration.
• Water Expulsion- Once the oxygen is absorbed and carbon dioxide is expelled, the water, now low in oxygen and rich in carbon dioxide, is pushed out through openings called gill slits.

Question- What makes amphibians unique in terms of their respiratory mechanisms? 

Answer- Respiratory Mechanisms of Amphibians-

Amphibians have versatile respiratory mechanisms that allow them to respire in various environments-

• Skin Respiration- Amphibians have permeable skin that allows for the direct exchange of gases with their environment. Oxygen can enter directly through the skin, and carbon dioxide can exit, facilitating respiration even in the absence of lung breathing.
• Gills- Some amphibians, particularly during their larval stages (e.g., tadpoles), possess gills. Gills enable them to extract oxygen directly from water, which is essential for survival in aquatic habitats.
• Lungs- As amphibians mature, they often develop lungs, enabling them to breathe air. Lungs allow for the intake of oxygen from the atmosphere and the expulsion of carbon dioxide, facilitating survival in terrestrial environments.

The combination of skin, gills, and lungs allows amphibians to adapt to a variety of respiratory conditions, whether in water or on land, making their respiratory mechanisms uniquely versatile.

Question- How have different animals evolved unique respiratory systems, and what does this indicate about them? 

Answer- Evolution of Unique Respiratory Systems in Different Animals-

Different animals have evolved unique respiratory systems to adapt to their specific environments and lifestyles. This diversity in respiratory mechanisms indicates their ecological adaptations and survival strategies. Here’s a concise explanation-

• Mammals (Humans, Cows, Dogs)-
  • Mammals possess well-developed lungs.
  • The diaphragm and ribcage play a crucial role in inhalation and exhalation.
  • This system is suitable for a terrestrial lifestyle, ensuring efficient oxygen intake and carbon dioxide expulsion.
• Insects (like Beetles)-
  • Insects respire through a network of tracheae and spiracles.
  • This system allows direct gas exchange with body cells, suiting their small size and minimising water loss, essential for various habitats.
• Fish-
  • Fish use gills to extract oxygen from water.
  • Gills are specialised to allow efficient gas exchange in aquatic environments, supporting their underwater survival.
• Amphibians (like Frogs)-
  • Amphibians use a combination of skin, lungs, and, occasionally, gills.
  • This adaptability supports their dual life – in water during early stages and on land as adults.
• Plants-
  • Plants use stomata on leaves and stems for respiration.
  • Roots also participate in gas exchange, ensuring that every part of the plant receives necessary gases.

Question- Can you elaborate on the process of cellular respiration in plants? 

Answer- Cellular Respiration in Plants-

Cellular respiration is a vital process in plants that allows them to extract energy from the food they produce. Here’s a detailed breakdown of the process-

• Basics of Cellular Respiration-
  • Just like in animals, the cellular respiration in plants involves the breakdown of glucose. This glucose is derived from the photosynthesis process.
  • The main aim is to produce energy in the form of ATP (Adenosine Triphosphate), which fuels various cellular activities.
• Aerobic Respiration-
  • When oxygen is present, plants carry out aerobic respiration.
  • Glucose breaks down with the use of oxygen, producing carbon dioxide, water, and releasing energy.
  • This process is highly efficient and yields a significant amount of ATP.
• Anaerobic Respiration-
  • In the absence or scarcity of oxygen, plants might undergo anaerobic respiration.
  • This breakdown of glucose without oxygen yields less energy compared to its aerobic counterpart and may produce by-products like alcohol.
• Sites of Respiration-
  • While the entire plant undergoes respiration, specific sites like mitochondria in plant cells play a pivotal role. Here, the glucose undergoes various metabolic pathways, like the Krebs cycle, to produce ATP.
• Gas Exchange-
  • The plant’s roots absorb air from the soil. For the aerial parts of the plant, tiny pores called stomata on leaves allow for the exchange of gases, ensuring that oxygen enters the plant cells and carbon dioxide is expelled.
  • This gas exchange supports the process of cellular respiration.

Question- How do different parts of plants contribute to the overall process of respiration? 

Answer- Respiration in Different Parts of Plants-

• Leaves-
  • Stomata, tiny pores on leaves, play a crucial role by facilitating gas exchange. They allow oxygen to enter and carbon dioxide to be expelled, supporting the cellular respiration process.
• Roots-
  • Roots also participate in respiration. They take in oxygen present in the soil air spaces. The oxygen absorbed is used for breaking down glucose, thus releasing energy required by the plant.
• Stem-
  • The stem contains small openings known as lenticels which assist in the exchange of gases, thus participating indirectly in the respiration process.
• Flowers and Fruits-
  • These parts also respire by utilising the oxygen to break down glucose, which is vital for their growth and development.
• Mitochondria-
  • Within the cells of these plant parts, mitochondria play an essential role as the site where most of the respiratory activities occur. Glucose is broken down here into water and carbon dioxide, releasing energy.

Question- How does the respiration mechanism in plants compare with other organisms like humans and fishes? 

Answer- 

Aspect	Plants	Humans	Fishes
Gas Exchange Organs	Stomata in leaves, lenticels in stems, and roots.	Lungs, mouth, and nose.	Gills.
Gas Exchange Process	Exchange of gases occurs passively through stomata and lenticels.	Inhalation and exhalation actively through lungs using diaphragm.	Gills extract dissolved oxygen from water and remove carbon dioxide.
Respiration Sites	All living cells of the plant (leaves, stems, roots).	Mitochondria in cells throughout the body.	Mitochondria in cells throughout the body.
Oxygen Source	Oxygen from the air, and roots take in oxygen from the soil air.	Atmospheric oxygen inhaled through the respiratory system.	Dissolved oxygen in water taken in through the gills.
Carbon Dioxide Release	Mainly through stomata during the day and night.	Exhaled through the nose and mouth to the atmosphere.	Released into water through gills.
Adaptation	Adapted to minimal movement, less oxygen requirement.	Adapted for more active movement, higher oxygen demand.	Adapted to aquatic life, efficient in extracting oxygen from water.

Explanation-

• Plants- Gas exchange in plants mainly happens through stomata and lenticels, allowing oxygen and carbon dioxide to move passively. All living parts participate in cellular respiration. Due to their stationary nature, plants have adaptations resulting in less oxygen requirement.
• Humans- Humans have a specialised respiratory system, actively inhaling oxygen and exhaling carbon dioxide. Every cell in the human body is involved in cellular respiration. Humans are adapted for a range of physical activities, requiring various oxygen levels.
• Fishes- Fishes are adapted to aquatic life, using gills for gas exchange, which allows them to extract dissolved oxygen from water efficiently. Like in humans, cellular respiration occurs in all living cells, meeting energy needs essential for their survival and activity in aquatic environments.

Question- What impacts do environmental conditions, like the availability of oxygen, have on the process of respiration in plants? 

Answer- Oxygen Availability and Plant Respiration

• Oxygen Role in Respiration- Oxygen is essential for the process of cellular respiration in plants. It helps in breaking down glucose into energy, carbon dioxide, and water.
• Oxygen Sources for Plants- Plants get oxygen from the air through stomata and lenticels. Roots also absorb oxygen present in the soil.
• Oxygen-Deficient Conditions- In scenarios where oxygen availability is low, such as waterlogged soils, plants might resort to anaerobic respiration, which is less efficient and results in incomplete breakdown of glucose.
• Effect on Energy Production- Limited oxygen availability reduces the energy produced during respiration. This could affect various physiological processes in plants, like growth and nutrient uptake.
• Adaptations- Plants may adapt to low oxygen environments by enhancing the efficiency of oxygen utilisation or developing aerenchyma tissues to facilitate oxygen transportation within the plant.

Question- How does the breathing rate and depth of breaths change during exercise compared to rest? 

Answer-Breathing Rate and Depth During Exercise vs. Rest

• During Rest-
  • Breathing Rate- At rest, an average person takes about 12-20 breaths per minute. This provides adequate oxygen to sustain the body’s basal metabolic rate.
  • Depth of Breaths- The depth of each breath is relatively shallow as the body’s demand for oxygen is low.
• During Exercise-
  • Breathing Rate– During physical activity, the body requires more oxygen to produce energy, so the breathing rate increases significantly. Depending on the intensity of the exercise, it can increase to over 40-50 breaths per minute or even higher in trained athletes.
  • Depth of Breaths- The depth of each breath also increases, meaning more air is inhaled and exhaled with each breath. This allows for a higher volume of oxygen to be taken in and carbon dioxide to be expelled.
• Reason for Change-
  • As physical activity is initiated, muscles work harder and require more energy. This energy is derived from the process of cellular respiration, which uses oxygen to break down glucose into energy. To meet the increased demand for oxygen, the body responds by increasing both the rate and depth of breathing.
  • Additionally, increased physical activity leads to a higher production of carbon dioxide, a waste product of cellular respiration. A faster and deeper breathing pattern helps in efficiently expelling this increased CO₂ from the body.

Question- Can you elaborate on how yeasts are utilised in the production of alcoholic beverages? 

Answer- Yeasts perform anaerobic respiration during the production of alcoholic beverages such as beer and wine. 

• Yeasts utilise the process of anaerobic respiration or fermentation in the absence of oxygen to convert glucose present in grains or fruits into alcohol (ethanol) and carbon dioxide.
• During anaerobic respiration in yeasts, energy is released from food without utilising oxygen. This is a vital process in the production of various alcoholic beverages.
• The production of alcohol through fermentation by yeasts is utilised in brewing industries to create beverages like beer, where the breakdown of glucose occurs in the absence of oxygen, producing alcohol as a by-product.

Question- What is the purpose of increased breathing rate and depth during exercise? 

Answer- The purpose of an increased breathing rate and depth during exercise is to meet the higher demand for oxygen by the muscles. During exercise, muscles work harder, requiring more energy. This energy is obtained through cellular respiration, a process that uses oxygen to break down glucose and release energy.

• Increased Oxygen Intake- By breathing faster and deeper, the body takes in more oxygen, essential for cellular respiration in muscle cells.
• Removal of Carbon Dioxide- An increased breathing rate also helps in expelling carbon dioxide, a waste product of cellular respiration, more efficiently from the body.

This ensures that muscles receive enough oxygen to produce the necessary energy for exercise and helps remove waste products, preventing muscle fatigue and maintaining endurance.

Question- How does anaerobic respiration in yeasts differ from typical respiration processes?

Answer- 

Feature	Anaerobic Respiration in Yeasts	Typical (Aerobic) Respiration
Oxygen Dependency	Does not require oxygen. Yeasts undergo fermentation in the absence of oxygen, which is a type of anaerobic respiration.	Requires oxygen. Oxygen is utilised to completely break down glucose into carbon dioxide and water in a process called cellular respiration.
Energy Production	Less energy is produced because glucose is only partially broken down.	More energy is produced because glucose is completely broken down.
Byproducts	Produces ethanol (alcohol) and carbon dioxide as byproducts. This is why yeasts are used in brewing and baking industries.	Produces carbon dioxide and water as byproducts, which are released during exhalation.
Applications/Usage	Commonly used in industries like brewing and baking for alcohol production and dough rising.	Occurs in the cells of living organisms (including humans) to produce energy necessary for life processes.

Question- Could you elaborate on how sneezing acts as a defence mechanism for the respiratory system? 

Answer- Sneezing as a Defense Mechanism for the Respiratory System–

Sneezing is a vital reflex action of the respiratory system, primarily serving as a defence mechanism. It functions to-

• Expel Irritants- Sneezing helps in removing irritants such as dust, pollen, or smoke that may have entered the nostrils and could potentially harm the respiratory system.
• Prevent Infection- Foreign particles, including microbes, can invade our respiratory system. When these particles are detected, a sneeze can forcefully eject them, thus reducing the risk of infections like the common cold or flu.
• Clear the Airway- By expelling air at high speed, sneezing ensures that any blockage or obstruction in the nasal passage is effectively cleared, ensuring smooth airflow.
• Nasal Lubrication- The sneeze response can stimulate the production of mucus. This mucus can trap foreign particles, further assisting in keeping the airways clean. Additionally, it keeps the nasal passages moist.

Question- How does oxygen play a role in cellular respiration and the survival of various organisms?

Answer- Role of Oxygen in Cellular Respiration and Survival of Organisms-

Oxygen is essential for cellular respiration and the survival of most organisms, as it plays a crucial role in the process of energy production within cells. Here’s how-

• Energy Release- Oxygen is used to break down glucose in the cells, a process that releases energy. This energy is necessary for the survival and functioning of living organisms.
• Aerobic Respiration- When oxygen is available, cells perform aerobic respiration. This type of respiration is efficient, producing a significant amount of energy from the glucose consumed.
• Supporting Physical Activity- During physical activities, the demand for energy in muscles increases. Oxygen is crucial in fulfilling this enhanced energy need by facilitating the breakdown of more glucose.
• Optimising Energy Production- In the presence of oxygen, the breakdown of glucose is complete, ensuring that maximum energy is obtained from each glucose molecule.

Supporting Various Life Forms- Different organisms, such as humans, animals, and plants, rely on oxygen to perform cellular respiration, ensuring their survival and proper functioning.

Also Check – What is Respiration Class 7 – Chapter 10- Respiration in Organisms

Also Check –What is Cellular Respiration Class 7 – Chapter 10- Respiration in Organisms

Also Check –Class 7 Science -Chapter 10- Respiration in Organisms- Complete Notes

Also Check –NCERT Solutions for Class 7 Science Chapter 10 Respiration in Organisms

Also Check –Class 7 science -Chapter 10- Respiration in Organisms– Definition and Explanation of Important Keywords

Also Check –Chapter 10- Respiration in Organisms–Class 7 science Question and Answer (Short)

Also Check –Chapter 10- Respiration in Organisms–Class 7 science Question and Answer (MCQs)

Also Check –Chapter 10- Respiration in Organisms–Class 7 science- Question and Answer (Fill in the Blanks)