Question 1

Question 1Differentiate between the following pairs on the basis of the aspect given in the brackets.(a) Aerobic and anaerobic respiration (end products of the process)(b) Respiration and photosynthesis (gas released)(c) Photosynthesis and respiration (reactants)(d) Respiration and breathing (organs involved)(e) Tidal volume and residual volume (quantity of air)

Accepted Answer

(a) Aerobic and anaerobic respiration (end products of the process)Aerobic respirationAnaerobic respirationCarbon dioxide, water, ATP, Heat energyLactic acid, ATP, heat energy(b) Respiration and photosynthesis (gas released)RespirationPhotosynthesisCarbon dioxideOxygen(c) Photosynthesis and respiration (reactants)PhotosynthesisRespirationWater, carbon dioxide, sunlightGlucose (with/without oxygen)(d) Respiration and breathing (organs involved)RespirationBreathingLungs, bronchi, alveoliNasal cavity, trachea, diaphragm(e) Tidal volume and residual volume (quantity of air)Tidal volumeResidual volume500 mL1500 mL

Question 2

Question 3With regard to the respiratory system and the process of respiration in man, answer the following questions:(a) Name the two muscles that help in breathing.(b) Briefly describe how the above mentioned muscles help in the inspiration of air.(c) Give the overall chemical equation to represent the process of respiration in humans.(d) What is meant by:Residual airDead air space

Accepted Answer

(a) The two muscles that help in breathing are — intercostal muscles and abdominal muscles.(b) When the intercostal muscles stretch between the ribs, they move outwards and inwards causing them to enlarge the chest cavity.(c) The overall chemical equation for the process of respiration in humans is as given below:C6H12O6+6O2→enzymes6CO2+6H2O+38 ATPchemical energy+420 kcalheat energy	ext{C}_6	ext{H}_{12}	ext{O}_6 + 6	ext{O}_2 \xrightarrow{	ext{enzymes}} 6	ext{CO}_2 + 6	ext{H}_2	ext{O} + \underset{	ext{chemical energy}}{38 	ext{ ATP}} + \underset{	ext{heat energy}}{420 	ext{ kcal}}C6​H12​O6​+6O2​enzymes​6CO2​+6H2​O+chemical energy38 ATP​+heat energy420 kcal​(d) The meanings of Residual air and Dead air space are as follows:Residual Air — Even after forcibly breathing out, some air always remains in the lungs. This air is referred to as residual air. The volume of this air is 1500mL.Dead air space — Some tidal air is remaining in the respiratory passages such as bronchi and trachea. Here no gas diffusion takes place. This volume is referred to as dead air space and its volume is 150mL.

Question 3

Question 5What are the functions of the following in breathing?(a) Ribs(b) Diaphragm(c) Abdominal muscles

Accepted Answer

(a) Ribs — The ribs move upwards and outwards due to the contraction of the external intercostal muscles stretched between them thus enlarging the chest cavity all around. (The internal intercostal muscles are relaxed).(b) Diaphragm — The diaphragm contracts and flattens from the dome shaped outline to an almost horizontal plane and thus contributes to the enlargement of the chest cavity lengthwise.(c) Abdominal muscles — It helps to increase the size of the thoracic cavity through the motion of the diaphragm which assists in inspiration.

Question 4

Question 1(x)Which of the following produces mucus in the respiratory passage?Ciliated cellsAir sacsGoblet cellsTertiary bronchi

Accepted Answer

Goblet cellsReason — Goblet cells make mucus which traps dust particles.

Question 5

Question 1(xi)During inspiration in humans the diaphragm and external intercostal muscles:Both contractContract and relax respectivelyBoth relaxRelax and contract respectively

Accepted Answer

Both contractReason — During inspiration the diaphragm contracts and moves downward, increasing the vertical space in the thoracic cavity. The external intercostal muscles also contract, pulling the ribs upward and outward, increasing the volume of the chest cavity. This increases the thoracic volume and reduces pressure, allowing air to flow into the lungs.

Question 6

Question 2Write the overall chemical equation representing the above definition of respiration.

Accepted Answer

C6H12O6+6O2→enzymes6CO2+6H2O+38 ATPchemical energy+420 kcalheat energy	ext{C}_6	ext{H}_{12}	ext{O}_6 + 6	ext{O}_2 \xrightarrow{	ext{enzymes}} 6	ext{CO}_2 + 6	ext{H}_2	ext{O} + \underset{	ext{chemical energy}}{38 	ext{ ATP}} + \underset{	ext{heat energy}}{420 	ext{ kcal}}C6​H12​O6​+6O2​enzymes​6CO2​+6H2​O+chemical energy38 ATP​+heat energy420 kcal​

Question 7

Question 6How is the respiratory passage kept free of dust particles?

Accepted Answer

The nasal cavity is lined by ciliated epithelium and mucous glands. The mucous glands secrete mucous. The ciliated epithelium is present on the entire lining of the trachea, larynx, bronchioles and bronchi. The constant motion of cilia and mucous trap dust, micro-organisms, pollen and other minute particles present in the air. In this way, the respiratory passage is kept free of dust particles.

Question 8

Question 8Write the balanced chemical equations for the following:(a) Aerobic respiration(b) Anaerobic respiration in plants(c) Anaerobic respiration in animals(d) Photosynthesis(e) Phosphorylation

Accepted Answer

(a) Aerobic respirationC6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATP + 420 kcal(b) Anaerobic respiration in plantsC6H12O6 → 2C2H5OH + 2CO2 + 2ATP(c) Anaerobic respiration in animalsC6H12O6 → 2C3H6O3 (lactic acid) + 2ATP(d) Photosynthesis6CO2 + 12H2O →chlorophyllsunlight\xrightarrow[	ext{chlorophyll}]{	ext{sunlight}}sunlightchlorophyll​ C6H12O6 + 6H2O + 6O2↑(e) PhosphorylationADP + Pi (inorganic phosphate) → ATP

Question 9

Question 9Define:(a) Respiration(b) Hypoxia(c) Asphyxiation(d) Breathing(e) Vital capacity

Accepted Answer

(a) Respiration — Respiration is the biochemical process of releasing energy by breaking down glucose for carrying out life processes.(b) Hypoxia — Hypoxia is the deficiency of oxygen reaching the tissue. It may occur due to over crowding with poor ventilation or at high altitudes.(c) Asphyxiation — Asphyxiation is a condition in which the blood becomes more venous by accumulation of more carbon dioxide and the oxygen supply is diminished.(d) Breathing — Breathing is a physical process in which the atmospheric air is taken in and forced out of the oxygen-absorbing organs, the lungs.(e) Vital capacity — Vital Capacity is defined as the volume of air that can be taken in and expelled out by maximum inspiration and expiration. It is 4500 ml.

Question 10

Question 4The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.The following diagram shows a group of the lung volumes and capacities:Study the diagram carefully and explain briefly the following:Tidal volumeInspiratory reserve volumeExpiratory reserve volumeVital capacityResidual volume

Accepted Answer

Tidal volume — It is the air breathed in and out in a normal quiet breathing. The tidal volume(TV) is 500mL.Inspiratory reserve volume — Air that can be drawn in forcibly over and above the tidal air is known as inspiratory reserve volume. It is referred to as IRV or complemental air and is 3000mL.Expiratory reserve volume — It is the air that can be expelled out forcibly after a normal expiration. It is referred to as ERV or supplemental air and is 1000mL.Vital capacity (VC) — It is the volume of air that can be inhaled and exhaled by maximum inspiration and expiration respectively and is about 4500mL.Residual volume (RV) — Even after forcible expiration, there is some air left in the lungs and is referred to as residual volume. It is about 1500mL.

Question 11

Question 7Given below is a part of the human respiratory system showing the air passage in the nose and throat. Read the information below the diagram and fill in the blanks with the technical terms of each structure.Human respiratory system consists of organs from nose to lungs. These organs are responsible for air passage and the diffusion of respiratory gases (oxygen and carbon dioxide) into the blood stream.The (a) ............... helps to breathe and smell. The nasal chamber opens at the back into a wide cavity, called (b) ............... situated at the back of the mouth. It leads into an air tube, called (c) ............... and the (d) ............... located dorsally behind the windpipe. The entrance to the windpipe is guarded by a flap called (e) .............. which closes at the time of swallowing food.

Accepted Answer

The Nose helps to breathe and smell. The nasal chamber opens at the back into a wide cavity, called Pharynx situated at the back of the mouth. It leads into an air tube, called Trachea and the Oesophagus located dorsally behind the windpipe. The entrance to the windpipe is guarded by a flap called Epiglottis which closes at the time of swallowing food.

The Respiratory System

Long Answer Type

Multiple Choice Type

Progress Check 1

Short Answer Type

Structured Application Skill Type

Very Short Answer Type