Mix Examples- Breathing and Exchange of Gases Questions in English

(D) Whales are mammals that breathe air using lungs. However, they can remain submerged for extended periods due to the presence of a specialized network of blood vessels called $Rete \text{ } mirabile$. This structure helps in storing extra oxygen and managing blood flow, allowing the animal to stay underwater for a long time.

(C) Frogs respire through their skin (cutaneous respiration),lungs (pulmonary respiration),and the lining of the buccal cavity (buccopharyngeal respiration).
$A$ muscular,dome-shaped diaphragm is a characteristic feature found in mammals that aids in the process of breathing.
Frogs do not possess a diaphragm; therefore,option $(c)$ is the correct answer.

(C) Plants growing in dry conditions (xerophytes) develop specific adaptations in their leaves to reduce the rate of transpiration.
One such adaptation is the rolling of leaves during the middle of the day to minimize surface area exposed to sunlight and dry air.
Ammophila (marram grass) is a classic example of a xerophytic plant that exhibits this behavior.

(A) Scotoactive stomata are those that open during the night and remain closed during the day. This mechanism is an adaptation in succulent plants to minimize water loss through transpiration in arid environments. Among the given options,$Opuntia$ is a succulent plant that exhibits this behavior. Therefore,the correct option is $A$.

(D) Stomatal movement is classified based on the time of opening and closing.
$1$. $Alfalfa$ type: Stomata remain open throughout the day and night,closing only for a few hours in the evening.
$2$. $Potato$ type: Stomata remain open throughout the day and night,closing only for a few hours at night.
$3$. $Bean$ type: Stomata open during the day and close during the night. This is the most common type found in thin-leaf mesophytes.
$4$. $Barley$ type: Stomata remain open only for a few hours during the day.
Therefore,the correct classification for stomata that open during the day and close at night is the $Bean$ type.

(C) The correct answer is $C$.
$I. Zelitch$ $(1963)$ proposed the glycolate theory for stomatal opening.
According to this theory,under low $CO_2$ concentration,photorespiration occurs in guard cells,leading to the production of glycolic acid.
The oxidation of glycolic acid produces $H_2O_2$ and glyoxylic acid,which increases the osmotic pressure of the guard cells,resulting in the influx of water and the opening of stomata.

(C) In dogs,the tongue is very moist and richly supplied with blood capillaries. During panting,the tongue swells and hangs out of the mouth,and the blood circulation within it increases significantly. The evaporation of water from the surface of the tongue cools the blood,which then circulates throughout the body. This process helps the dog in thermo-regulation.

(D) $1$. Respiratory centres are indeed located in the medulla oblongata and pons,which regulate the rhythm of respiration.
$2$. Near the lungs,the partial pressure of $CO_2$ is low. This causes the reverse chloride shift (Hamburger phenomenon),where $Cl^-$ ions move out of the $RBC$ into the plasma as bicarbonate ions move into the $RBC$ to form $CO_2$ for exhalation.
$3$. $RBC$ of deoxygenated blood are slightly larger than those of oxygenated blood because the entry of $HCO_3^-$ ions into the $RBC$ (via the chloride shift in tissues) increases the osmotic pressure,causing water to enter the cell,making it swell.
$4$. Since all the statements $A$,$B$,and $C$ are scientifically correct,the correct choice is $D$.

(C) Respiration is a comprehensive physiological process that involves multiple stages.
$1$. Breathing (Ventilation): The physical process of taking in oxygen and releasing carbon dioxide.
$2$. External Respiration: The exchange of gases between the alveoli of the lungs and the blood.
$3$. Cellular Respiration: The metabolic process within cells where glucose is oxidized to produce energy $(ATP)$ with the release of carbon dioxide and water.
Therefore,respiration encompasses all these stages.

(A) During intense physical activity or exercise,the rate of $O_2$ supply to the muscles by the lungs becomes insufficient to meet the metabolic demand.
As a result,muscles undergo anaerobic respiration,leading to the accumulation of lactic acid.
The body compensates for this by increasing the breathing rate to enhance $O_2$ intake,a state known as oxygen debt.

(D) During rest,the metabolic activity of the body is at its lowest level.
Since metabolic processes require oxygen $(O_2)$ and produce carbon dioxide $(CO_2)$,a decrease in metabolic rate leads to a reduction in the demand for oxygen and the production of carbon dioxide.
To maintain homeostasis,the body adjusts its physiological parameters:
$1$. The rate of breathing decreases to match the lower oxygen requirement.
$2$. The pulse rate (heart rate) decreases to reduce the workload on the heart as less blood flow is needed for gas exchange.
$3$. The overall $O_2$ intake and $CO_2$ output are minimized.
Therefore,all these parameters are indicative of the body's metabolic state during rest.

(A) The total pulmonary ventilation is directly proportional to the metabolic rate of the body.
This is because an increase in metabolic activity,such as during physical exercise,requires more oxygen consumption and higher carbon dioxide production,which necessitates an increase in pulmonary ventilation to maintain homeostasis.
Conversely,during states of low metabolic activity,such as sleep,the pulmonary ventilation decreases.

(A) At high altitude,the $P{O_2}$ of alveolar air falls because of low ${O_2}$ tension in the atmosphere.
As a result,the body compensates for the reduced oxygen availability by increasing the breathing rate to intake more air.
Additionally,the heart beat increases to ensure that the required amount of ${O_2}$ is transported to the tissues efficiently.

(C) The respiration rate is lowest while sleeping (which is often associated with snoring).
During sleep,the metabolic demand of the body is at its minimum,leading to a decreased requirement for oxygen and a lower rate of carbon dioxide production,which results in a reduced breathing rate.
In contrast,activities like playing tennis or running significantly increase the metabolic rate and oxygen demand,thereby increasing the respiration rate.
Eating food involves mechanical processes that do not necessarily lower the respiration rate compared to the resting state of sleep.

(B) The correct answer is $B$. The term pleura refers to the double-layered serous membrane that covers the lungs and lines the thoracic cavity. The double-layered covering of the kidney is known as the renal capsule. Therefore,the statement in option $B$ is false.

(D) At high altitudes,the partial pressure of oxygen $(pO_2)$ in the atmosphere is significantly lower than at sea level.
To compensate for this low oxygen availability and to maintain adequate tissue oxygenation,the body undergoes several physiological adaptations.
These include an increase in the number of erythrocytes ($RBC$ count),an increase in haemoglobin concentration,and an increase in the respiratory and heart rates.
Furthermore,the oxygen-haemoglobin dissociation curve shifts to the right (Bohr effect) to facilitate the unloading of oxygen to the tissues.
Therefore,all the given options are correct physiological responses to high-altitude living.

(B) At higher altitudes,the partial pressure of oxygen in the air is lower (hypoxia).
To compensate for this reduced availability of oxygen and to facilitate rapid gaseous exchange,the body increases the production of $RBCs$ (erythropoiesis).
Therefore,the correct reason is that there is less oxygen available at higher altitudes.

(C) The atmosphere has a limited capacity to hold water vapour at a specific temperature.
When the air contains the maximum amount of water vapour it can hold at that temperature,it is said to be saturated.
This state is referred to as the saturation point.
Relative humidity is the ratio of the actual amount of water vapour present to the maximum amount the air could hold at that temperature,while absolute humidity is the actual mass of water vapour in a given volume of air.

(B) Breathing involves two main stages: inspiration and expiration.
During inspiration,the diaphragm muscles contract,which increases the volume of the thoracic cavity in the antero-posterior axis.
This increase in thoracic volume leads to a decrease in intrapulmonary pressure compared to atmospheric pressure,forcing air into the lungs.
As the lungs fill with air,the chest cavity expands.
Therefore,all the provided statements correctly describe the physiological process of breathing.

(D) $1$. About $20-25\%$ of $CO_2$ is transported by $RBCs$ in the form of carbaminohemoglobin.
$2$. About $97\%$ of $O_2$ is transported by $RBCs$ in the blood,bound to hemoglobin.
$3$. About $70\%$ of $CO_2$ is transported as bicarbonates $(HCO_3^-)$ in the plasma.
$4$. Since all the given statements are scientifically accurate,the correct option is $D$.

(A) Statement $(a)$ is correct: RBCs contain a very high concentration of the enzyme carbonic anhydrase.
Statement $(b)$ is incorrect: Blood plasma contains only a minute quantity of carbonic anhydrase.
Statement $(c)$ is correct: Every $100 \ ml$ of deoxygenated blood delivers approximately $4 \ ml$ of $CO_2$ to the alveoli for elimination.
Statement $(d)$ is incorrect: $20-25\%$ of $CO_2$ is carried by hemoglobin as carbaminohemoglobin,not oxyhemoglobin. Oxyhemoglobin is the form in which oxygen is transported.

(A) At high altitudes,the partial pressure of oxygen $(PO_2)$ is lower than at sea level. To compensate for this reduced oxygen availability,the human body produces more erythropoietin,which stimulates the bone marrow to produce more red blood cells $(RBCs)$. This increase in the number of $RBCs$ enhances the oxygen-carrying capacity of the blood,allowing the body to function efficiently despite the lower oxygen levels in the environment.

(A) The respiratory rate of an animal is inversely proportional to its body size.
Smaller animals have a higher metabolic rate and,consequently,a higher respiratory rate to meet their oxygen demands.
$A$ rabbit is a small mammal with a relatively high metabolic rate.
Its normal respiratory rate typically ranges between $30$ and $60$ breaths per minute.

(C) Abdominal breathing,also known as diaphragmatic breathing,is a type of breathing that occurs when the diaphragm contracts and the abdomen expands. In clinical contexts,it is often associated with rapid or labored breathing (tachypnea) when the thoracic muscles are fatigued or restricted,or it can be a compensatory mechanism. However,in the context of general biological terminology,it is often used to describe a shift in breathing pattern during respiratory distress or increased effort,which is typically rapid.

(C) The respiratory rate of a newborn baby is significantly higher than that of an adult.
An adult typically has a respiratory rate of $12-16$ breaths per minute.
In contrast,a newborn baby has a respiratory rate of approximately $30-60$ breaths per minute.
This higher rate is necessary to meet the high metabolic demands of the rapidly growing infant body.

(D) Respiration involves the following steps:
$1$. Breathing or pulmonary ventilation by which atmospheric air is drawn in and $CO_2$ rich alveolar air is released out.
$2$. Diffusion of gases ($O_2$ and $CO_2$) across alveolar membrane.
$3$. Transport of gases by the blood.
$4$. Diffusion of $O_2$ and $CO_2$ between blood and tissues.
$5$. Utilization of $O_2$ by the cells for catabolic reactions and resultant release of $CO_2$ (cellular respiration).
Option $D$ describes the provision of nutrition,which is a function of the circulatory and digestive systems,not a step in the process of respiration.

(B) At high altitudes $(> 3,500 \ m)$,the atmospheric pressure is low,which results in low oxygen availability (hypoxia).
To compensate for this low oxygen,the human body undergoes physiological acclimatization:
$(1)$ The breathing rate increases to intake more air.
$(2)$ The production of red blood cells (erythropoiesis) increases to enhance the oxygen-carrying capacity of the blood.
Therefore,the correct changes are $(2)$ and $(3)$.

(A) Sunken stomata are a characteristic adaptation of xerophytic plants to reduce the rate of transpiration.
$Nerium$ (Oleander) is a classic example of a xerophyte that possesses sunken stomata located in depressions called stomatal crypts.
$Mangifera$ (Mango) is a mesophyte,$Hydrilla$ is a hydrophyte,and $Zea$ $mays$ (Maize) is a typical monocot mesophyte,none of which exhibit sunken stomata.

(C) Respiratory gases are the gases that are exchanged during the process of respiration in living organisms.
Oxygen $(O_2)$ is taken in by organisms for cellular respiration to produce energy.
Carbon dioxide $(CO_2)$ is produced as a metabolic waste product during cellular respiration and is expelled from the body.
Therefore,both oxygen and carbon dioxide are considered respiratory gases.

(A) Hemoglobin is a respiratory pigment found in red blood cells that facilitates the transport of respiratory gases like $O_2$ and $CO_2$ in the blood.
Chlorophyll is a green pigment found in chloroplasts that absorbs light energy to perform photosynthesis,which is essential for the production of food in plants.

(A) The correct answer is $A$. When individuals move from plains to high-altitude regions like Rohtang Pass,they initially experience altitude sickness due to low atmospheric pressure and reduced oxygen availability. However,after staying for about six months,the body undergoes physiological acclimatization. This process involves:
$1$. Increasing the production of red blood cells $(RBCs)$ to enhance oxygen-carrying capacity.
$2$. Decreasing the binding affinity of haemoglobin to $O_2$ (shifting the oxygen dissociation curve to the right),which facilitates the release of oxygen into the tissues.
$3$. Increasing the breathing rate to compensate for low oxygen levels.

(D) : The circulatory system of insects is open,whereby blood (haemolymph) flows freely through the body cavity (haemocoel). Insects possess a tracheal system for respiration,where oxygen is delivered directly to tissues via tubes called tracheae,bypassing the blood. Haemolymph does not contain an oxygen-carrying pigment like $Hb$ (haemoglobin); therefore,it does not assist in the transport of oxygen.

(A) When individuals from plain areas move to high altitudes ($3,500 \ m$ or more),they experience hypoxia due to low atmospheric pressure and reduced oxygen availability.
To compensate for this,the body initiates several physiological adjustments:
$1$. Increased breathing rate: This helps in taking in more air to compensate for the lower partial pressure of oxygen.
$2$. Increased red blood cell production (erythropoiesis): The kidneys release the hormone erythropoietin,which stimulates the bone marrow to produce more red blood cells,thereby increasing the oxygen-carrying capacity of the blood.
Therefore,the correct changes are $(ii)$ and $(iii)$.

(B) The statement in option $B$ is false because the excretory system is primarily responsible for the removal of metabolic wastes from the body,not the exchange of respiratory gases. The exchange of respiratory gases ($O_2$ and $CO_2$) is the primary function of the respiratory system and the circulatory system.
Option $A$ is a general definition of respiration involving gas exchange.
Option $C$ is correct as oxygen is essential for aerobic respiration to produce $ATP$.
Option $D$ is correct because cellular respiration involves the breakdown of complex molecules like glucose into simpler ones,which is a catabolic process.

(B) Respiration involves several steps:
$1$. Breathing or pulmonary ventilation by which atmospheric air is drawn in and $CO_2$ rich alveolar air is released out.
$2$. Diffusion of gases ($O_2$ and $CO_2$) across alveolar membrane.
$3$. Transport of gases by the blood.
$4$. Diffusion of $O_2$ and $CO_2$ between blood and tissues.
$5$. Utilization of $O_2$ by the cells for catabolic reactions and resultant release of $CO_2$ (cellular respiration).
Option $B$ states 'Transport of gases by the tissue',which is incorrect because gases are transported by the blood,not by the tissues.

(B) $1$. $97\%$ of $O_2$ is transported by $RBC$ (hemoglobin),so $1-q$.
$2$. $70\%$ of $CO_2$ is transported as bicarbonate ions in the plasma,so $2-p$.
$3$. $100$ $ml$ of oxygenated blood delivers $5$ $ml$ of $O_2$ to the tissues,so $3-s$.
$4$. $100$ $ml$ of deoxygenated blood delivers $4$ $ml$ of $CO_2$ to the lungs,so $4-r$.
Therefore,the correct matching is $(1-q), (2-p), (3-s), (4-r)$.

(A, C) Statement $A$ is correct: Cigarette smoking is a major cause of chronic bronchitis,which involves the inflammation of the bronchi.
Statement $B$ is incorrect: The pneumotaxic center in the pons region of the brain primarily moderates the functions of the respiratory rhythm center and can reduce the duration of inspiration.
Statement $C$ is correct: In certain industries,especially those involving grinding or stone-breaking,so much dust is produced that the defense mechanism of the body cannot fully cope with the situation. Long-term exposure can give rise to inflammation leading to fibrous proliferation (fibrosis) and thus cause serious lung damage.
Statement $D$ is incorrect: Only about $20-25\%$ of $CO_2$ is carried by haemoglobin as carbamino-haemoglobin. About $70\%$ is carried as bicarbonate and $7\%$ is dissolved in plasma.

(B) $1$. $A$ healthy human breathes approximately $12-16$ times per minute.
$2$. Under normal physiological conditions,every $100 \, ml$ of oxygenated blood delivers approximately $5 \, ml$ of $O_2$ to the tissues.
Therefore,the correct values for $X$ and $Y$ are $12-16$ and $5 \, ml$ respectively.

(A) Sunken stomata are a characteristic adaptation of xerophytic plants to reduce the rate of transpiration.
Among the given options,$Nerium$ (Oleander) is a xerophytic plant that possesses sunken stomata located in pits to minimize water loss.
$Hydrilla$ is a submerged hydrophyte,while Mango and Guava are mesophytes.

(C) At high altitudes,the atmospheric pressure is low,which leads to a lower partial pressure of oxygen $(pO_2)$.
This results in hypoxia (low oxygen availability in tissues).
To compensate for this reduced oxygen supply,the body stimulates the production of erythropoietin from the kidneys.
Erythropoietin stimulates the bone marrow to produce more red blood cells $(R.B.C.s)$,thereby increasing the oxygen-carrying capacity of the blood.
Therefore,the $R.B.C.$ count increases in humans living at high altitudes.

(A) At high altitudes,the atmospheric pressure decreases,which leads to a lower partial pressure of oxygen $(pO_2)$.
This results in hypoxia (low oxygen availability in the tissues).
To compensate for the reduced oxygen availability,the body increases the production of red blood cells (erythropoiesis) to enhance the oxygen-carrying capacity of the blood.
Therefore,individuals living at high altitudes have a higher count of red blood cells compared to those living at sea level.

(A) When people from low-altitude regions (plain dwellers) move to high altitudes ($3500 \ m$ or more),they experience altitude sickness due to low atmospheric pressure and low oxygen availability.
To compensate for the low oxygen levels (hypoxia),the body undergoes physiological acclimatization:
$1$. The breathing rate increases to intake more oxygen from the thin air.
$2$. The production of red blood cells (erythropoiesis) increases to enhance the oxygen-carrying capacity of the blood.
Therefore,the correct changes are $(ii)$ and $(iii)$.

(A) When people migrate from plains to high-altitude areas like Rohtang Pass,the atmospheric pressure decreases,leading to lower oxygen availability (hypoxia). To compensate,the body undergoes acclimatization by increasing the production of $RBC$s to carry more oxygen and decreasing the binding affinity of hemoglobin to $O_2$ (shifting the oxygen-hemoglobin dissociation curve to the right),which facilitates the release of oxygen to the tissues. $A$ period of six months is sufficient for the body to adapt to these changes. Therefore,the correct option is $A$.

(A) Mammalian skin is thick and keratinized,making it impermeable to gases,which helps in preventing water loss.
Because mammals have high metabolic rates,they require a significantly higher amount of oxygen compared to lower animals.
Since cutaneous respiration (skin breathing) is insufficient to meet these high oxygen demands,mammals have evolved a complex respiratory system consisting of the nasal cavity,nasopharynx,larynx,trachea,bronchi,bronchioles,and lungs to provide a large surface area for gas exchange.
Therefore,both the Assertion and the Reason are correct,and the Reason correctly explains why a complex respiratory system is necessary in mammals.

(N/A) Metabolism is a fundamental characteristic of all living organisms,involving various chemical reactions that sustain life.
Organisms utilize oxygen $(O_{2})$ to break down nutrient molecules,such as glucose $(C_{6}H_{12}O_{6})$,through cellular respiration to derive energy in the form of $ATP$ for performing biological activities.
As a byproduct of this oxidative breakdown,carbon dioxide $(CO_{2})$ is produced within the cells.
To maintain homeostasis,$O_{2}$ must be continuously supplied to the cells,and the metabolic waste $CO_{2}$ must be expelled from the body.
The process of exchanging atmospheric $O_{2}$ with $CO_{2}$ produced by the cells is known as breathing or ventilation,which is a critical component of the broader process of respiration.
The respiratory system facilitates this gas exchange between the atmosphere and the blood,while the circulatory system transports these gases between the lungs and the body tissues.

(N/A) The process of respiration involves the following steps:
$1$. Breathing or pulmonary ventilation: Atmospheric air is drawn in,and $CO_2$-rich alveolar air is released out.
$2$. Diffusion of gases: Exchange of $O_2$ and $CO_2$ occurs across the alveolar membrane.
$3$. Transport of gases: $O_2$ and $CO_2$ are transported by the blood throughout the body.
$4$. Diffusion of gases: Exchange of $O_2$ and $CO_2$ occurs between the blood and the tissues.
$5$. Cellular respiration: Utilization of $O_2$ by the cells for catabolic reactions and the resultant release of $CO_2$.

(A-D) $H_2O$ and $CO_2$ form $H_2CO_3$ in large amounts with the help of carbonic anhydrase,which dissociates into $H^+$ and $HCO_3^-$.
$(1)$ This $HCO_3^-$ moves out of the erythrocyte and reacts with $KHb$ to form $KHCO_3$,causing an ionic imbalance. If the osmotic pressure increases,water enters the erythrocytes,which may cause them to burst due to swelling.
To balance this,$Cl^-$ enters the erythrocyte from the blood plasma. This process is known as the chloride shift or Hamburger phenomenon. Thus,$Cl^-$ translocation is necessary to maintain the integrity of erythrocytes.
$(2)$ Smoking destroys the ciliated epithelium of the respiratory tract,which prevents the removal of dust particles and bacteria. Consequently,the accumulation of these particles and bacteria leads to uncontrolled cell division,inducing cancer. Therefore,smoking significantly increases the probability of lung cancer.

(D) In the lungs,the partial pressure of $CO_{2}$ is lower in the alveoli than in the blood,causing $CO_{2}$ to diffuse out of the blood.
Specifically,bicarbonate ions $(HCO_{3}^{-})$ in the plasma enter the erythrocytes and combine with $H^{+}$ ions to form carbonic acid $(H_{2}CO_{3})$.
Carbonic acid is then broken down by the enzyme carbonic anhydrase into $H_{2}O$ and $CO_{2}$.
This $CO_{2}$ diffuses from the blood into the alveoli and is subsequently exhaled during expiration.
This process is the inverse of the reactions occurring in the systemic tissues,where $CO_{2}$ is loaded into the blood.

(A) The process of respiration involves the following steps in sequence:
$1$. $(d)$ Pulmonary ventilation: Atmospheric air is drawn in and $CO_2$ rich alveolar air is released out.
$2$. $(a)$ Diffusion of gases ($O_2$ and $CO_2$) across the alveolar membrane.
$3$. $(b)$ Transport of gases by the blood.
$4$. $(e)$ Diffusion of $O_2$ and $CO_2$ between blood and tissues.
$5$. $(c)$ Utilisation of $O_2$ by the cells for catabolic reactions and resultant release of $CO_2$.
Therefore,the correct sequence is $(d), (a), (b), (e), (c)$.

(A) $(1)$ The Inspiratory Capacity $(IC)$ is the total volume of air a person can inspire after a normal expiration. It is calculated as $IC = TV + IRV$. Given $TV$ (Tidal Volume) is approximately $500 \ mL$ and $IRV$ is $2500-3000 \ mL$,then $IC = 500 + (2500-3000) = 3000-3500 \ mL$.
$(2)$ When $CO_2$ binds to hemoglobin,it forms carbamino-hemoglobin. Similarly,when oxygen binds to hemoglobin,it forms oxy-hemoglobin.