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All questions of Respiration for Grade 9 Exam

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In insects, air enters the body through
  • a)
    Spiracles
  • b)
    Gills
  • c)
    Lungs
  • d)
    Skin
Correct answer is option 'A'. Can you explain this answer?

Maitri Sarkar answered
Insect bodies have openings, called spiracles, along the thorax and abdomen. These openings connect to the tubular network, allowing oxygen to pass into the body, regulating the diffusion of CO2 and water vapor. 

Which of the following animal can breathe through skin as well through lungs?
  • a)
    fish
  • b)
    mammal
  • c)
    cockroach
  • d)
    frog
Correct answer is option 'D'. Can you explain this answer?

Ameya Dasgupta answered
Frogs breathe through their skin as well as their lungs for the following reasons:
-It is an amphibious animal that can live both in water and land.
-On land, lungs play a very important role in the respiration process by inhaling oxygen and exhaling carbon dioxide
-When frogs are inside the water, they breathe through the skin.

In plants, exchange of gases takes place through
  • a)
    Guard cells
  • b)
    Epidermis
  • c)
    Stomata
  • d)
    Accessories cells
Correct answer is option 'C'. Can you explain this answer?

Maitri Sarkar answered
The exchange of oxygen and carbon dioxide in the leaf (as well as the loss of water vapor in transpiration) occurs through pores called stomata.

Normally stomata open when the light strikes the leaf in the morning and close during the night.

 Chest cavity is surrounded by
  • a)
    12 pair of ribs                     
  • b)
    10 pair of ribs 
  • c)
    11 pair of ribs                     
  • d)
    25 ribs.
Correct answer is option 'A'. Can you explain this answer?

Sai Kumar answered
The thoracic cavity is surrounded by a bony skeleton, with 12 ribs on each side originating from their respective thoracic vertebrae posteriorly and extending anteriorly. The upper seven ribs are connected directly to the sternum via their respective costal cartilages, whereas the 8th to 10th ribs are connected to the sternum via a fused common costal cartilage and the lower two ribs remain free floating and unconnected with the sternum. This skeletal structure provides optimal protection to the intrathoracic organs against all but the most significant trauma.

Haemoglobin carries oxygen molecules as
  • a)
    Carboxy-pigement.
  • b)
    Carboxyhaemoglobin
  • c)
    Oxyhaemoglobin
  • d)
    Chloroplast
Correct answer is option 'C'. Can you explain this answer?

Kavita Joshi answered
Hemoglobin: The protein inside red blood cells (a) that carries oxygen to cells and carbon dioxide to the lungs is hemoglobin Hemoglobin is made up of four symmetrical subunits and four heme groups. Iron associated with the heme binds oxygen. It is the iron in hemoglobin that gives blood its red color.Oxyhemoglobin is formed during physiological respiration when oxygen binds to the heme component of the protein hemoglobin in red blood cells. This process occurs in the pulmonary capillaries adjacent to the alveoli of the lungs.

Identify the labelled parts P, Q and R in the figure given below. 
  • a)
    P- Bronchus; Q- Bronchiole, R- Alveolus
  • b)
    P- Trachea; Q- Alveolus, R- Bronchus
  • c)
    P- Bronchus; Q- Bronchiole, R- Diaphragm
  • d)
    P- Trachea; Q- Bronchus, R- Diaphragm
Correct answer is option 'D'. Can you explain this answer?

Learning Education answered
The trachea, commonly known as the windpipe, is a tube about 4 inches long and less than an inch in diameter in most people. The trachea begins just under the larynx (voice box) and runs down behind the breastbone (sternum). The trachea then divides into two smaller tubes called bronchi: one bronchus for each lung.
The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.
The diaphragm is an unpaired, dome shaped skeletal muscle that is located in the trunk. It separates the thoracic and abdominal cavities from each other by closing the inferior thoracic aperture. The diaphragm is the primary muscle that is active in inspiration.

Diaphragm present in mammals is
  • a)
    Membrane between external and middle ear
  • b)
    Membrane around the brain
  • c)
    Partition between the thoracic and abdominal cavities
  • d)
    Membrane around lungs.
Correct answer is option 'C'. Can you explain this answer?

Lakshmi Reddy answered
The muscular partition between thoracic cavity and abdominal cavity is called the diaphragm, which is known as the primary inspiratory muscle that accounts for greater than 50% of tidal volume.
It is required for quiet breathing.
In addition to this, the muscle is shaped like a dome and is located in the inner ribs.

Muscular floor of the chest cavity is called
  • a)
    Rib cage
  • b)
    Diaphragm
  • c)
    Trachea
  • d)
    Bronchus
Correct answer is option 'B'. Can you explain this answer?

Akshara Bajaj answered
The muscular floor of chest cavity is called diaphragm. It is responsible for expanding and contracting chest cavity to inhale and exhale.

Voice box is present in
  • a)
    Pharynx
  • b)
    Epiglottis
  • c)
    Mouth
  • d)
    Larynx
Correct answer is option 'D'. Can you explain this answer?

Nitin Patel answered
Voice box is responsible for producing sound in human beings. It is present in larynx.

Small thin walled balloon like structure that help in exchange of gases are
  • a)
    Arteries
  • b)
    Veins
  • c)
    Stomata
  • d)
    Alveoli
Correct answer is option 'D'. Can you explain this answer?

Rithika Roy answered
Small thin walled balloon like structure that help in exchange of gasses are called alveoli. Lung is made of large number of alveoli.

Instant source of energy is
  • a)
    Sugar
  • b)
    Fat
  • c)
    Vitamins
  • d)
    Glucose
Correct answer is option 'D'. Can you explain this answer?

Pranjal Banerjee answered
Glucose is called as instant source of energy because glucose neednot be digested and directly get oxidised to give energy.

Alcohol is obtained by anaerobic fermentation of
  • a)
    Fat
  • b)
    Minerals
  • c)
    Protein
  • d)
    Sugar
Correct answer is option 'D'. Can you explain this answer?

Akanksha Yadav answered
Alcohol is obtained by anaerobic fermentation of Sugar in which incomplete oxidation of food takes place to release carbon dioxide and alcohol.

What is the normal range of breathing rate per minute for an average adult at rest?
  • a)
    9-12
  • b)
    15-18
  • c)
    21-24
  • d)
    30-33
Correct answer is option 'B'. Can you explain this answer?

Shiksha Academy answered
The normal breathing rate for an average adult at rest is 15-18 breaths per minute. This rate can vary based on factors such as age, fitness level, and overall health.

The chemical used to test the carbon dioxide gas in exhaled air is
  • a)
    Lime water
  • b)
    Lime stone
  • c)
    Lime juice
  • d)
    Quick lime
Correct answer is option 'A'. Can you explain this answer?

Srishti Reddy answered
Lime water is used to test the carbon dioxide gas in inhaled air because lime water turns milky in presence of carbon dioxide.

Why does an athlete breathe faster and deeper than usual after finishing a race?
  • a)
    To reduce muscle cramps
  • b)
    To supply more oxygen to the cells
  • c)
    To expel excess carbon dioxide
  • d)
    None of these
Correct answer is option 'B'. Can you explain this answer?

Subset Academy answered
Athletes breathe faster and deeper after a race to supply more oxygen to their cells. During intense physical activity, the body's demand for energy is high, but the oxygen supply is limited. This leads to anaerobic respiration in muscle cells. After the race, rapid and deep breathing helps replenish the oxygen deficit. Interestingly, some athletes practice controlled breathing techniques to improve their performance and recovery.

Which of the following animals breathe through skin as well as through lungs?
  • a)
    Fish
  • b)
    Frog
  • c)
    Cockroach
  • d)
    Earthworm
Correct answer is option 'B'. Can you explain this answer?

Shiksha Academy answered
Animals that breathe through skin as well as through lungs:


  • Frog: Frogs are amphibians that have the ability to breathe through their skin as well as through their lungs. Their skin is thin and moist, allowing for gas exchange to occur. This is especially important for frogs when they are underwater or in environments with low oxygen levels.


Explanation:


  • Frogs have a specialized skin that is permeable to gases, allowing them to absorb oxygen and release carbon dioxide through their skin.

  • When frogs are on land, they primarily use their lungs to breathe. However, when they are in water or in damp environments, they rely more on their skin for respiration.

  • This dual breathing system allows frogs to adapt to different environments and survive in a variety of conditions.


Conclusion:


  • In conclusion, frogs are a unique example of animals that can breathe through their skin as well as through their lungs, showcasing their remarkable adaptation to varying habitats.

What is the process in cells where breakdown of food happens with the use of oxygen called?
  • a)
    Aerobic respiration
  • b)
    Anaerobic respiration
  • c)
    Photosynthesis
  • d)
    Cell division
Correct answer is option 'A'. Can you explain this answer?

Gayatri Mukherjee answered
Understanding Aerobic Respiration
Aerobic respiration is the process by which cells break down food molecules in the presence of oxygen to release energy. This process is crucial for the survival of most living organisms, as it provides the energy required for various cellular activities.

Key Features of Aerobic Respiration:
- **Oxygen Requirement:**
Aerobic respiration occurs only in the presence of oxygen. This is a key differentiator from anaerobic respiration, which happens without oxygen.
- **Energy Production:**
The main purpose of aerobic respiration is to produce ATP (adenosine triphosphate), the energy currency of the cell. One glucose molecule can yield up to 36-38 ATP molecules during aerobic respiration.
- **Process Overview:**
The process involves several steps, mainly:
- **Glycolysis:** This occurs in the cytoplasm, where glucose is partially broken down into pyruvate, producing a small amount of ATP.
- **Krebs Cycle:** In the mitochondria, pyruvate is further broken down, releasing carbon dioxide and transferring energy to electron carriers.
- **Electron Transport Chain:** This final stage occurs in the inner mitochondrial membrane, where oxygen acts as the final electron acceptor, allowing ATP to be produced efficiently.

Importance of Aerobic Respiration:
- **Sustains Life:**
It provides the energy necessary for growth, repair, and maintenance of cells.
- **Waste Products:**
The by-products of aerobic respiration, primarily carbon dioxide and water, are less toxic compared to those produced during anaerobic respiration.
In summary, aerobic respiration is a vital process that utilizes oxygen to efficiently break down food and produce energy, sustaining life in various organisms.

During exhalation, in which direction do the ribs move?
  • a)
    Outwards
  • b)
    Downwards
  • c)
    Upwards
  • d)
    To normal position
Correct answer is option 'B'. Can you explain this answer?

Coders Trust answered
During exhalation, i.e. releasing air during respiration, the ribs move downwards to reduce the volume of the thoracic cavity.
During exhalation, your diaphragm relaxes and moves upward into the chest cavity. The intercostal muscles between the ribs also relax to reduce the space in the chest cavity. As they relax they position the rib cage downwards and inwards.

Which of these are parts of the human respiratory system?
(i) Larynx 
(ii) Nostrils
(iii) Gullet
(iv) Windpipe
(v) Lungs
  • a)
    (ii) and (v) only
  • b)
    (i), (ii), (iv) and (v) only
  • c)
    (i), (iv) and (v) only
  • d)
    All of the above
Correct answer is option 'B'. Can you explain this answer?

Aurora Institute answered
Parts of Respiratory System includes:
  • External nostrils – For the intake of air.
  • Nasal chamber – which is lined with hair and mucus to filter the air from dust and dirt.
  • Pharynx – It is a passage behind the nasal chamber and serves as the common passageway for both air and food.
  • Larynx – Known as the soundbox as it houses the vocal chords, which are paramount in the generation of sound.
  • Epiglottis – It is a flap-like structure that covers the glottis and prevents the entry of food into the windpipe.
  • Trachea – It is a long tube passing through the mid-thoracic cavity.
  • Bronchi – The trachea divides into left and right bronchi.
  • Bronchioles – Each bronchus is further divided into finer channels known as bronchioles.
  • Alveoli – The bronchioles terminate in balloon-like structures known as the alveoli.
  • Lungs – Humans have a pair of lungs, which are sac-like structures and covered by a double-layered membrane known as pleura.

Plants breathe through their stomata located in their
  • a)
    Leaves
  • b)
    Stem
  • c)
    Flowers
  • d)
    Roots
Correct answer is option 'A'. Can you explain this answer?

Indu Gupta answered
Stomata are microscopic pores found on the surface of leaves and are responsible for gas exchange.
They allow plants to take in carbon dioxide and release oxygen, playing a crucial role in photosynthesis and respiration.

The classification table given below shows how different organisms breathe.
Which of these organisms are correctly represented by X, Y and Z?   
  • a)
  • b)
  • c)
  • d)
Correct answer is option 'A'. Can you explain this answer?

Coders Trust answered
Option (a)
X = Tadpole with gills is correct.
Y = Whale with lungs is correct.
Z = Earthworm with skin is correct.
Therefore option (a) is fully correct.
Option (b)
X = Fish with gills is correct.
Y = Crocodile with lungs is correct.
Z = Cockroach with skin is wrong because cockroach breathes through tracheae, not skin.
Option (c)
X = Frog with gills is wrong because only tadpoles have gills, adult frogs use lungs and skin.
Y = Shark with lungs is wrong because sharks breathe with gills, not lungs.
Z = Toad with skin is wrong because toads mainly breathe with lungs and only partly through skin.
Option (d)
X = Prawn with gills is correct.
Y = Grasshopper with lungs is wrong because grasshoppers breathe through tracheae.
Z = Cockroach with skin is wrong because cockroaches also breathe through tracheae.
Thus the only correct option is (a).
 

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