Access to the AP 7th Class Science Study Material 6th Lesson Respiration in Organisms Questions and Answers are aligned with the curriculum standards.
AP 7th Class Science 6th Lesson Respiration in Organisms Questions and Answers
AP Board Solutions Class 7 Science Chapter 6 Respiration in Organisms
Exercise
Question 1.
Why does an athlete breathe faster and deeper than usual after finishing the race?
Answer:
During the run, the demand of energy but the supply of oxygen to produce energy is limited. When the athlete runs in the race, his body needs more energy. In order to get extra energy, the athlete breathes faster. Because more oxygen is supplied to our cells. It is because of the breakdown of food and more energy is released.
Question 2.
List the similarities and differences between aerobic and anaerobic respiration.
Answer:
Similarities:
- In both aerobic and anaerobic respiration, the food is broken down to release energy.
- Both occurs inside the cell.
- Both produce energy.
- Both produce by products.
- Food is oxidised in both cases and energy is released.
Differences :
| S.No. | Aerobic respiration | Anaerobic respiration |
| 1) | It takes place in the presence of oxygen. | It takes place in the absence of oxygen. |
| 2) | It occurs in all organisms like mammals. | It occurs in lower organisms like yeast and bacteria. It can occur in the muscles of higher organisms during heavy activities. |
| 3) | It is a slow process. | It is a fast process. |
| 4) | In this process, glucose is completely broken down into CO2, water along with the release of energy. | In this process, glucose is broken into alcohol, CO2 and energy. |
| 5) | Energy is released in higher amount. | Energy is released in lower amount. |
Question 3.
Why do we often sneeze when we inhale a lot of dust-laden air?
Answer:
When we inhale dust-laden air, dirt particles enter the nostrils. These particles get trapped in the hair present in the nasal cavity and they irritate the lining of the cavity which results in sneezing.
Question 4.
Take three test-tubes. Fill 3/4th of each with water.Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?
Answer:
Living organisms use oxygen and release CO2 during respiration. Test tube A consists of snail which continuously uses the oxygen produced and releases carbon dioxide. Hence, test tube A will have the highest concentration of carbon dioxide.
Question 5.
Tick the correct answer:
a) In cockroaches, air enters the body through:
i) lungs
ii) gills
iii) spiracles
iv) skin
Answer:
iii) spiracles ( ✓ )
b) During heavy exercise, we get cramps in the legs due to the accumulation of:
i) carbon dioxide ii) lactic arid
iii) alcohol
iv) water
Answer:
ii) lactic acid (✓)
c) Normal range of breathing rate per minute in an average adult person at rest is:
i) 9 – 12
ii) 15 – 18
iii) 21 – 24
iv) 30 – 33
Answer:
ii) 15-18 (✓)
d) During exhalation, the ribs:
i) move outwards
ii) move downwards
iii) move upwards
iv) do not move at all
Answer:
ii) move downwards (✓)
Question 6.
Match the items in Column I with those in Column II:
| Column I | Column II |
| a) Yeast | i) Earthworm |
| b) Diaphragm | ii) Gills |
| c) Skin | iii) Alcohol |
| d) Leaves | iv) Chest cavity |
| e) Fish | v) Stomata |
| f) Frog | vi) Lungs and skin |
Answer:
| Column I | Column II |
| a) Yeast | iii) Alcohol |
| b) Diaphragm | iv) Chest cavity |
| c) Skin | i) Earthworm |
| d) Leaves | v) Stomata |
| e) Fish | ii) Gills |
| f) Frog | vi) Lungs and skin |
Question 7.
Mark ‘T’ if the statement is true and ‘F’ if it is false:
i) During heavy exercise, the breathing rate of a person slows down. (T/F)
ii) Plants carry out photosynthesis only during the day and respiration only at night. (T/F)
iii) Frogs breathe through their skins as well as their lungs. (T/F)
iv) The fishes have lungs for respiration. (T/F)
v) The size of the chest cavity increases during inhalation. (T/F)
Answer:
i) False
ii) False
iii) True
iv) False
v) True
Question 8.
Given below is a square of letters in which are hidden different words related to respiration in organisms. These words may be present in any direction – upwards,’ downwards, or along the diagonals. Find the words for your respiratory system. Clues about those words are given below the square:
i) The air-tubes of insects
ii) Skeletal structures surrounding’ chest cavity
iii) Muscular floor of chest cavity
iv) Tiny pores on the surface of leaf
v) Small openings on the sides of the body of an insect
vi) The respiratory organs of human beings
vii) The openings through which we inhale
viii) An anaerobic organism
ix) An organism with tracheal system.
Answer:
i) Trachea
ii) Ribs
iii) Diaphragm
iv) Stomata
v) Spiracles
vi) Lungs
vii) Nostrils
viii) Yeast
ix) Ant
Question 9.
The mountaineers carry oxygen with them, because:
a) At an altitude of more than 5 km , there is no air.
b) The amount of air available to a person is less than that available on the ground.
c) The temperature of air is higher than that on the ground.
d) The pressure of air is higher than that on the ground.
Answer:
b) The amount of air available to a person is less than that available on the ground.
Questions given in the lesson
Page No. 118
Question 1.
Boojho noticed that when he released his breath after holding it for some time, he had to breathe heavily. Can you tell him why it was so ?
Answer:
The rate of breathing is fixed in every organism. When we hold our breath for a few moments oxygen content decreases in our body.As all cells require oxygen for respiration, upon releasing breath, the body tries to take in more oxygen to make up for this period of deficiency. Hence, as a reflex the body starts breathing heavily.
Page No. 120
Question 2.
Paheli wants to know why we yawn when we are sleepy or drowsy.
Answer:
When we feel sleepy rate of respiration slows down. The lungs do not get enough oxygen from the air resulting in yawning. Yawning brings more oxygen and compensate oxygen level.
Page No. 126
Question 3.
Boojho wants to know how much air a person can hold in the lungs.
Answer:
On an average, the amount of air that can be held by a person’s lungs varies between 4 litres to 6 litres. This is also known as the lung capacity. It also varies from person to person depending upon the age, gender, diseases, etc.
Page No. 128
Question 4.
Boojho wants to know if cockroaches, snails, fish, earthworms, ants and mosquitoes also have lungs.
Answer:
Cockroaches, fishes, earthworms, ants and mosquitoes don’t have lungs.
Page No. 130
Question 5.
Boojho has seen in television programmes that whales and dolphins often come up to the water surface. They even release a fountain of water sometimes while moving upwards. Why do they do so?
Answer:
Whales and dolphins do not have gills to take in oxygen dissolved in water during respiration.They have to come up to the surface to breath air. While doing so, they open their nose also called a blowhole situated on top of their head. It blows out a gust of old moist air in a spout of air and water as they breathe.
Question 6.
Paheli wants to know whether roots, which are underground also take in oxygen. If so, how ?
Answer:
Roots also take in oxygen. They fulfill this requirement from the air spaces between the soil particles.
Extended Learning – Activities and Projects
Question 1.
Observe fish in an aquarium. You will find flap like structures on both sides of their heads. These are flaps which cover the gills. These flaps open and close alternately. On the basis of these observations, explain the process of respiration in the fish.
Answer:
Respiration in fish takes place with the help of gills. Most of the fishes possess gills only on either side of their head. Gills are the tissues made up of feathery structures, that provide a large surface area for gaseous exchange. A large surface area is crucial for gaseous exchange in aquatic organisms as water contains very little amount of dissolved oxygen.
When the fish takes water in its mouth, it reaches the gills, which in turn extract the dissolved oxygen, and the remaining amount of water is given out through the slits present in the gills. The blood transports this absorbed oxygen to all parts of the body.The blood also brings back the carbon dioxide from the other body parts, which is then expelled through gills into the water present in the surroundings.
Question 2.
Visit a local doctor.Learn about the harmful effects of smoking. You can also collect material on this topic from other sources. You can seek help of your teacher or parents. Find out the percentage of people of your area who smoke. If you have a smoker in your family, confront him with the material that you have collected.
Answer:
Some harmful effects of smoking on our body are:
- Smoking paves the way to hard drugs. Tobacco has been used by human beings for more than 400 years. It is smoked, chewed or used as a stuff.
- Smoking is associated with increasing incidents of cancer of lungs, urinary bladder and throat, gastric ulcers, coronary heart diseases, etc.
- Tobacco chewing is associated with the increased risk of cancer of the oral cavity.
- Depression has been found to have a strong association with cigarette smoking. Adults who are depressed for 40 to 50% more likely to smoke than adults who are not depressed.
Question 3.
Visit a doctor. Find out about artificial respiration, Ask the doctor:
a) When does a person need artificial respiration?
b) Does the person need to be kept on artificial respiration temporarily or permanently?
c) From where can the person get supply of oxygen for artificial respiration?
Answer:
- Artificial respiration is needed by an individual at the time of acute breathing problems. It is an artificial method of breathing required when the person is unable to breathe normal.
- Artificial respiration is not provided permanently to every person. It is given temporarily to person suffering from breathing problems. But artificial respiration can also be provided permanently to those who are in coma or unable to breathe on his or her own.
- During artificial respiration, a cylinder filled with oxygen is attached to a machine which provides oxygen for artificial respiration.
Question 4.
Measure the breathing rate of the members of your family and some of your friends. Investigate:
a) If the breathing rate of children is different from that of adults.
b) If the breathing rate of males is different from that of females. If there is a difference in any of these cases, try to find the reason.
Answer:
a) The normal breathing rate in children ranges from 30 to 60 breaths per minute, while the normal breathing rate in adults is measured at 12 to 20 breaths per minute. Thus, the breathing rate in children is higher than that in adults.
b) Yes, the breathing rate of males varies from that of females. The breathing rate largely depends on the heart and lungs. Males possess higher lung and heart capacity than females, so males are able to achieve a higher rate than females.
Activity
Activity 6.1 Page No : 116
Question 1.
Close your nostrils and mouth tightly and look at a watch. What did you feel after some time? How long were you able to keep both of them closed? Note down the time for which you could hold your breath.
Answer:
We feel very suffocated when we keep our mouth and nose closed. This is because we cannot stay for so long without breathing.We able to keep them closed at most 30 seconds and up to 2 minutes
Question 2.
Generally we are not aware that we are breathing. However, if you try you can count your rate of breathing. Breathe in and out normally. Find out how many times you breathe in and breathe out in a minute? Did you inhale the same number of times as you exhaled? Now count your breathing rate (number of breaths/minute) after brisk walk and after running. Record your breathing rate as soon as you finish and also after complete rest. Tabulate your findings and compare your breathing rates under different conditions with those of your classmates.
Changes in breathing rate under different conditions
| Name of the classmate | Breathing rate | |||
| Normal | After a brisk walk for 10 minutes | After running fast 100 m | At rest | |
Answer:
Aim : To show the changes in breathing rate under different conditions.
Procedure :
- Breathe in and out normally.
- Find out how many times you breathe in and breathe out in a minute?
- Did you inhale the same number of times as you exhaled?
- Now count your breathing rate (number of breaths/minute) after brisk walk and after running.
- Record your breathing rate as soon as you finish and also after complete rest.
- Tabulate your findings and compare your breathing rates under different conditions with those of your classmates.
Observations: We observe the breathing rates differ based on the physical and physiological condition of the person. When we breathe faster we need extra energy.
Changes in breathing rate under different conditions
| Name of the classmate | Breathing rate | |||
| Normal | After a brisk walk for 10 minutes | After running fast 100 m | At rest | |
| Ramesh | 16 | 18 | 25 | 15 |
| Suresh | 14 | 17 | 25 | 16 |
| Radha | 15 | 19 | 22 | 14 |
| Moksha | 16 | 20 | 23 | 15 |
| Balakrishna | 14 | 20 | 25 | 14 |
| Self | 15 | 18 | 24 | 15 |
Conclusion: From the above activity we can conclude that the an adult at rest breathes in and out 15 to 18 times a minute. During heavy exercise breathing rate goes up to 25 times a minute.
Activity 6.3 Page No – 120
Question 3.
Figure shows the various activities carried out by
a person during a normal day. Can you say in which activity, the rate of breathing will be the slowest and in which it will be the fastest?
Answer:
Aim : To show the variation in the breathing rate during different activities.
Procedure: Perform the various activities as shown in the figure during a normal day and keenly observe your breathing rate.
Observation: We observe when we do different activities, the rate of breathing increase or decrease depending on the activity. During sleeping and sitting, the breathing rate is slow while when we are doing physical activities like running, jumping etc., the rate of breathing is fast.
Conclusion: From the above activity, breathing rate depends upon the activity we do. Breathing rate of a person is not constant and keeps it changing.
Activity 6.4 Page No – 124
Question 4.
Take a deep breath. Measure the size of the chest with a measuring tape (Figure) and record your observations in Table. Measure the size of the chest again when expanded and indicate which classmate shows the maximum expansion of the chest.
Answer:
Aim : To measure the change in size of the chest cavity during breathing.
Materials required : Measuring tape.
Procedure :
- Take a deep breath.
- Measure the size of the chest with a measuring tape (Figure) and record your observations.
- Do the same process with your classmates and record your observations.
- Now exhale complete air and measure the size again.
Observations : Effect of breathing on the chest size of some classmates.
| Size of the chest (cm) | ||||
| Name of the classmate | During inhalation | During exhalation | Difference in size | |
| Ravi | 75 | 71 | 5 | |
| Krishna | 73 | 67 | 3 | |
| Satya | 70 | 68 | 4 | |
| Self | 68 | 70 | 5 | |
Conclusion : From the above activity, we can conclude that the chest expands during inhalation and contracts during exhalation.
Question 5.
Take a wide plastic bottle. Remove the bottom. Get a Y-shaped glass or plastic tube. Make a hole in the lid so that the tube may pass through it. To the forked end of the tube fix two deflated balloons. Introduce the tube into the bottle. Now cap the bottle. Seal it to make it airtight. To the open base of the bottle tie a thin rubber or plastic sheet using a large rubber band. To understand the expansion of the lungs, pull the rubber sheet from the base downwards and watch the balloons. Next, push the rubber/ plastic sheet up and observe the balloons. Did you see any changes in the balloons? What do the balloons in this model represent? What does the rubber sheet represent?
Answer:
Aim: To demonstrate how diaphragm in the body helps in the process of breathing in and out of the air.
Materials required : Two glass bell jars, two Y-shaped glass tubes, two balloons, two rubber corks, two thin rubber sheets and piece of string.
Procedure:
- Take a wide plastic bottle.
- Remove the bottom.
- Get a Y-shaped glass or plastic tube.
- Make a hole in the lid so that the tube may pass through it.
- To the forked end of the tube fix two deflated balloons.
- Introduce the tube into the bottle as shown in Figure.
- Now cap the bottle. Seal it to make it airtight. Model to show mechanism of breathing
- To the open base of the bottle tie a thin rubber or plastic sheet using a large rubber band.
- To understand the expansion of the lungs, pull the rubber sheet from the base downwards and watch the balloons.
- Next, push the rubber/plastic sheet up and observe the balloons.
Observations : We observe when space in the jar is increased, balloons gets inflated while when space in the jar is decreased, balloon gets deflated.
Conclusion : From the above activity we can conclude that when the lungs are filled with air, the diaphragm moves downwards and when we exhale the diaphragm moves upward.
Activity 6.6 Page No : 126
Question 6.
Take a slender, clean test tube or a glass/plastic bottle.
Make a hole in its lid and fix it on the bottle. Pour some freshly prepared lime water in the test-tube. Insert a plastic straw through the hole in the lid in such a way that it dips in lime water. Now blow gently through the straw a few times (Figure). Is there a change in the appearance of lime water ?
Answer:
Aim : To show the effect of exhaled air on lime water.
Materials required : Test tube, lime water, straw.
Procedure:
- Take a slender, clean test tube or a glass/plastic bottle.
- Make a hole in its lid and fix it on the bottle.
- Pour some freshly prepared lime water in the test-tube.
- Insert a plastic straw through the hole in the lid in such a way that it dips in lime water.
- Now blow gently through the straw a few times.
Observation : We observe that the lime water becomes cloudy.
Conclusion : From the above activity we can conclude that exhaled air has carbon dioxide.