CBSE-iClass VII – Biology

Unit: 15Respiration in Organisms

CONTENTS

1. Preface2. Acknowledgement3. Syllabus4. Scope Document

i. Learning objectivesii. Extension Activitiesiii. Cross curricular links

5. Teacher Notes (TN)i. Matrix

ii. Teacher Guidelines for activitiesiii. Rubric: Assessment of learning

6. Teacher Student Support Material (TSSM) i. Introduction

ii. Importance of Respirationiii. Breathing and Respiration

a. Breathing Activity 1 Activity 2

b. Breathing rate Activity 3 Activity 4

c. Is breathing and Respiration the same?iv. Aerobic and Anaerobic Respiration

a. Aerobic Activity 5

b. Anaerobic Activity 6

v. Respiratory System of Humansa. Nose

Activity 7 Worksheet 1

b. Wind pipe/Tracheac. Lungs

d. Bronchi/Bronchiolesvi. Mechanism of Breathing

Activity 8 Activity 9 Worksheet 2

a. Journey of Oxygen and Carbon dioxide in body cells Worksheet 3

b. How is Energy consumed?vii. Breathing in Other Animals

a. Earthworm b. Cockroach c. Frogd. Fish Worksheet 3

viii. Respiration and Exchange of gases in Plants7. Post Content Worksheet 1

8. Post Content Worksheet 29. Glossary 10.E – Resources

Syllabus Importance of Respiration

Breathing and Respiration

Aerobic and Anaerobic respiration

Respiratory system of humans

Process of breathing in earthworm, cockroach and fish

Respiration and exchange of gases in plants

Scope Document

Learning Objectives

At the end of the unit the learners will be able to:

Understand that breathing is inhalation of air and exhalation of CO2.

Correlate the role of O2 in the breakdown of food in order to release energy.

Compare breathing with respiration.

Analyze that breathing is a physical process, which involves movement of lungs and respiration is a biochemical process which takes place though out the cell.

Differentiate between aerobic and anaerobic respiration

Define cellular respiration and state the steps of cellular respiration.

Describe the structure of various organs of human respiratory system and appreciate their role in the process of breathing.

Trace the journey of O2 and CO2 in the cells.

Familiarize themselves with the organs of breathing in other organisms such as Earthworm, cockroach and fish and relate it to their habitats.

Analyze that exchange of gases in plants is the result of respiration (which takes place all the time) and photosynthesis (which takes place in the presence of light)

Cross-Curricular links

Chemistry: Cellullar processes involve interaction of molecules and compounds in living organisms.

Chemical Equations to represent exchange of gases, O2 and CO2, H2O.

Physics: The role of diaphragm and chest muscles as that of an air pump.

Movements in thoracic region due to inhalation and exhalation. Role of pressure on breathing, lung capacity, rate of breathing.

English: Vocabulary Development

Information and Technology: Explore and making use of web links

Visual Art: Observing and drawing diagrams.

MatrixS No Content Learning outcome Skills1. Importance of

respiration Understand that

breathing is inhalation and exhalation of air.

Correlate the role of O2in the breakdown of food in order to release energy.

Represent the role of O2 in respiration through a word equation.

2. Breathing and Respiration

Differentiate between breathing and respiration.

Hands-on-experience Analyze that breathing is a

part of respiration physical process and cellular respiration is a biochemical process.

3. Aerobic and Anaerobic Respiration

Recognize the role of oxygen in aerobic respiration.

Gain knowledge that respiration can also occur in the absence of O2.

Differentiate between aerobic and anaerobic respiration

Interpret (types of respiration)

Experiential learning (muscle cramps)

Hands on experience. (scientific skill)

Appreciate release of energy in the absence of oxygen

4. Organs of Respiration in Human Being

Describe the structure of various organs of human respiratory system.

Relate the structure of respiratory organs to their functions.

Careful observation. Illustration

Appreciate the role of various organs involved in the process of inhalation and exhalation to their functions.

5. Mechanism of Breathing

Investigate the role of various organs in the mechanism of breathing.

Visualization Experimental skill. (learning

by doing)

6. The process of cellular respiration.

Trace the journey of O2

and CO2in the body cells.

Define cellular respiration

Comprehend the steps that occur in cellular respiration.

Making connections between nutrition and respiration

Realize how energy is released by oxidation of food in the cells

Analyze that breathing is a part of respiration physical process and cellular respiration is a biochemical process.

7. Breathing in other animals Ex: Earthworm, Cockroach, Frog and Fish

Familiarise with process of breathing in animals living in different habitats.

Relate the organs of breathing of different organisms to their respective habitat.

8. Exchange of gases in plants. Describe the

process of respiration in plants.

Analyze that exchange of gases in plants is the result of respiration (which takes place all the time) and photosynthesis (which takes place in the presence of sunlight)

Critically analyze that plants do not have complex organs for respiration.

Realize that photosynthesis and respiration takes place simultaneously in the presence of light whereas at night only respiration takes place.

Respiration in Organisms

Teacher Notes

This unit deals with respiration, a vital process for living organisms. It focuses on the fact that respiration is not the same as breathing.

The process of respiration includes breathing & release of energy. It highlights the difference between aerobic and anaerobic respiration and also appropriately describes the anatomy and physiology of the human respiratory system. Through this unit the learners will be exposed to the process of breathing in animals living in different habitats. This unit will also deal with exchange of gases in plants and highlight the same during photosynthesis and respiration.

Make a web chart of teaching points keeping in mind, the learning outcomes at the learners level of experience and comprehension.

Web Chart

Respiration in Organisms

Give an opportunity to the learners to recall that respiration is an important characteristic feature of living organisms. Allow the learners to discuss the importance of respiration and ask if this is the same as breathing.

Ask them if they have noticed the chest movements during the process of breathing and also ask them what do they do to inflate a balloon?

Before concluding from their answers, give them an activity (Activity I) through which they will associate inflating a balloon while they exhale during breathing. Ask them to do it 3-4 times and experience the process of inhalation and exhalation.

Breathing Aerobic

Release of energy Respiration Anaerobic

Respiratory system in Humans Breathing in other organisms

Organs of breathing Physiology of respiratory system Mechanism of breathing Animals Plants Cellular respiration * Soil - Earthworm Respiration & exchange of

(Release of energy) * Land – Insects gases * Amphibious – Frog

* Water – Fish

Organize a discussion in the class so that the learners share among themselves their view point on the change in the number of times they breathe while performing various activities such as cycling, swimming, jogging etc.

Give them Activity 2 and ask them to fill up the worksheet that follows. Inform them that one time inhalation and one time exhalation together should be counted as one breath. Ask each learner to count the number of times he/she breathes in one minute, after performing the activity according to the instructions given in the table in TSSM. Let them share their observation in the class. Also let them announce in

which activity the count is highest or lowest. Introduce and define the term rate of breathing.

As all the learners are aware that the exhaled air contains carbon dioxide and water vapours, give them the apparatus to device an activity (activity 3) to prove that exhaled air contains carbon dioxide.

Give them a hint that carbon dioxide turns lime water milky. Thereafter, they will conclude that exhaled air contains carbon dioxide.

Ask the learners if they have experienced or seen anyone cleaning spectacles or any glass surface by blowing on it and wiping it. Give them hands-on-experience by asking them to blow on the surface of a mirror (Activity 4). Summarize the observation by concluding that the mirror becomes hazy because there is condensation of water vapour into small droplets of water. This proves that exhaled air contains water vapour.

Ask the learners what they understand by the terms breathing and respiration. Based on their responses, connect the process of breathing with the utilization of oxygen to break down food, to release energy. Facilitate the learners to conclude that breathing is a part of respiration.

Explain to the learners that release of energy takes place in every cell, as breakdown of food takes place with the help of oxygen in every cell. Now define the term cellular respiration.

Introduce the term ATP as energy rich molecules released as a result of cellular respiration. Give them the expanded form of ATP.

Conclude by differentiating ‘breathing’ as a physical process, merely a gaseous exchange; from ‘cellular respiration’ as a biochemical process that involves oxidation of food to release energy.

Aerobic Respiration

Introduce the concept of aerobic respiration by demonstrating an experiment to show that organisms breathe in the presence of air.

Take the example of germinating seeds to prove that they consume only oxygen from the air they breathe in.

Set up the experiment by taking few KOH pellets or solution in a micro test tube. Suspend it in the conical flask with a string and attach it to the rubber stopper. KOH absorbs carbon dioxide from the air in the conical flask and the carbon dioxide exhaled by the germinating seeds.

Give an opportunity to the learners to observe the rise in the level of the coloured water in the delivery tube dipped in the beaker. Draw their attention to the set up as well as the diagram of the set up given in the TSSM.

Ask them the reason for the rise in the water level. You might be able to elicit the answer, if not, explain that it is due to the partial vacuum created in the conical flask. Reason out with them that this partial vacuum is created because oxygen present in the air in the conical flask is inhaled by the seeds and the carbon dioxide as mentioned earlier is absorbed by the KOH. This creates vacuum because of which the coloured water is sucked into the delivery tube. You could correlate the rising of the water with the suction pressure.

Teacher Guidelines

1. Soak gram seeds in water overnight. Remove them the following day and wrap them up in a damp cloth and leave it in a covered container. After 2 to 3 days when the seeds begin to germinate, they are ready for the experiment.

2. Take a conical flask and put the germinating seeds in it and cover it with a rubber stopper with single hole. Suspend a tiny test tube containing KOH solution with a thread before fixing the stopper.

3. Take a delivery tube bent in ‘U’ shape and dip one end into the coloured water, contained in a beaker.

4. The other end passes through the rubber stopper.5. The set up must be made air tight using Vaseline to seal the mouth

of the conical flask.

PRECAUTIONS:

1. Care should be taken to keep the germinating seeds moist at all times.

2. The apparatus should be made absolutely air tight.3. The delivery tube should be dipped in water.4. Facilitate the learners to conclude that germinating seeds utilize

oxygen to breathe. 5. Define Aerobic respiration and Introduce the term Aerobes for

organisms that need oxygen for respiration.

Anaerobic Respiration

Ask the learners if they can think of a living organism that respires in the absence of oxygen.

Elicit answers from them learners and demonstrate with an experiment (activity 5) that organisms such as yeasts, respire in the absence of oxygen.

Follow the procedure given in the TSSM and note precautions given below:-

PRECAUTIONS:

1. The test tube containing yeast in glucose solution must be kept in a water bath maintained at 37°C.

2. Leave the set up for 24 hours at least.

It may be noted that alcohol escapes very quickly when the cork is removed. Hence you may not be able to smell alcohol.

Represent the respiration in yeast in the form of a word equation. Define the term anaerobic respiration and introduce the term fermentation as anaerobic respiration in yeasts. Also make a contrast between aerobes and anaerobes by using the term anaerobes for organisms that respire in the absence of oxygen.

Draw the attention of learners that anaerobic respiration can occur in humans also and recall if they have ever experienced muscle cramps while running a race or playing. Ask them to observe the pictures in TSSM. Reason with the learners that during heavy exercises the body needs extra energy, for which more oxygen is required. Explain to them that to get that required energy the muscle cells break

down glucose partially into lactic acid, releasing some energy. Accumulation of lactic acid in the muscle cells leads to cramps. Relate it to the fact that this release of energy takes place in the absence of oxygen, hence known as anaerobic respiration.

Represent this in the form of a word equation also. Advice the learners that we can get rid of cramps by hot water bath or massage as this improves blood circulation thereby increasing supply of O2 to breakdown lactic acid completely into carbon dioxide and water.

After having dealt with Aerobic and Anaerobic respiration take up the detailed study of the respiratory system of the humans.

Human Respiratory System

Have a brainstorming session and elicit some information about the organs of breathing in humans. List the organs in the right sequence. Describe the structure of the organs and relate it to their functions as mentioned in the TSSM. Use illustration and refer to video clips mentioned, to reinforce the understanding of the learners.

Emphasize to the learners the role of hair and mucous present in the nostrils and perform an activity (Activity 6) to indicate the right way to breathe. With the help of Worksheet 1 that follows, they will be able to practice the right way to breathe.

Bring the attention of the learners to the diagram of the respiratory system in humans. Tell them to trace the path of the air from the nose, through the trachea, bronchi, bronchioles and alveoli in lungs and into the body cells.

Show them the videos (video links given in TSSM) of the mechanism of breathing and the illustration given in the TSSM to bring out the process of inhalation and exhalation.

Ask them to do an activity (Activity 7) to understand that the chest size increases during breathing. Through this activity make the learners realize that there is a variation in the chest size of different individuals.

To facilitate the learners to comprehend the mechanism of breathing better, give them hands-on-experience (Activity 8) by asking them to make a simple model that simulates the mechanism of breathing in humans. For the recapitulation of the process of inhalation and exhalation ask them to fill up Worksheet 2.

Take them through the journey of inhaled air and exhaled air and emphasize that though the path of their movement is the same yet the direction in which the inhaled air and exhaled air move is opposite to each other. Reinforce the same through Worksheet 3.

You have now reached a stage when you can rightly relate the process of nutrition with the release of energy during respiration.

With the help of the diagram of alveoli with a blood capillary given in TSSM, explain how oxygen diffuses into the blood capillaries and reaches the body cells. You can explain that it is here that the assimilated food breaks down (gets oxidized) to release energy. Clarify to the learners that since the energy is released in the body cells, this step of respiration is known as cellular respiration.

Emphasize once again that process of cellular respiration is a chemical process and breathing is a physical process. Also give a word equation to sum it up.

Explain the keywords giving their appropriate definition and usage to facilitate vocabulary development. Draw the attention of the learners to the process of breathing in other animals. To arouse their curiosity ask them to brainstorm how the animals of different habitats breathe. Ask the learners how animals living in moist soil breathe. Take the example of earthworms and explain that they breathe with the help of moist skin.

Compare the breathing surface of earthworms to that of the insects that have a hard body cover (exoskeleton). Take the example of a cockroach which has holes on the sides known as spiracles through which the air enters into the tracheal system and diffuses into the body cells. Ask them to observe the picture of an insect larva given in TSSM to notice the spiracles.

It will be interesting to take up the example of frog to find out from the learners how does it breathe. Let them recall that the frog lives in water and on land as it is an amphibian. Make them realize that the amphibians are a group of animals showing the transition from aquatic life to life on land signifying an evolutionary trend hence they need to breathe with the help of different organs while on land and in water. Introduce to them; lungs and buccal cavity as breathing organs when they are on land (The term buccal cavity may be explained to them with its significance). Also tell them that oxygen diffuses through their moist and slimy skin while they are in water.

Ask the learners if fish can survive out of water. Draw their attention to the structure of gills and how these facilitate gaseous exchange. Let the learners realize that the body of fish is covered with scales therefore air cannot diffuse into the body through the surface unlike in case of frog. Conclude by telling the learners that the organs of breathing of aquatic animals are not the same as those of amphibians.

Summarize by asking the learners to analyze and correlate that the organs of breathing in different animals depend on their habitat.

Respiration and Exchange of gases in Plants

Review the fact that plants also respire since they are living organisms. Highlight the characteristics features of plants while stating that they do not have complex organs for respiration. Emphasize that plants do not make breathing movements but gaseous exchange takes place in all organs of the plant body by simple diffusion. Let the learners correlate that exchange of gases in plants is the result of respiration (which takes place all the time) and photosynthesis (which takes place in the presence of light)

Let the learners realize that photosynthesis and respiration takes place simultaneously in the presence of light whereas at night only respiration takes place.

Conclude the study of this unit by summarizing that respiration is an important biological process in all living organisms and it is through respiration that the living organisms get the much needed energy for their survival.

RUBRIC: ASSESSMENT OF LEARNINGParameterLearner is able to

Beginning(1)

Partially Proficient (2) Proficient(3)

Exemplary(4)

Comprehend the concept of inhalation and differentiate it from exhalation O2 breaks food to release energy

Text book based In own words Use synonyms, other terms to express

Uses related terms and other examples to convey concept

Differentiate between breathing and respiration

Define respirationRespiration – biochemical processBreathing – Physiological process

In brief Uses given examples to explain and differentiate

Uses examples with explanation to differentiate

Uses specific but different words to explain differences

Differentiate between aerobic and anaerobic respiration

Just names without elaboration

Mentions a few examples and elaborates

Mentions more examples with better explanation

Focused on detailsAble to devise experiments to show the process

Structure and functions of Respiratory System in Man

Incomplete labeling of diagrams and just names parts from text

Completes diagrams well, with complete labeling

Discusses functions of parts with more examples

Uses specific words to explain functions and illustrates well and clearly

Investigate role of organs

Barely In brief Uses observation based examples to explain the role of organs

Uses related examples to explain

Trace journey of CO2 and O2Comprehend steps of cell respiration

Incomplete Nearly complete Discuss the pathways and steps in respiration

Uses specific words to convey the concept of transportation

Understands respiration in other organisms

Text book based In own words Discuss and elaborate with more examples

Uses more examples and makes connections with more organisms and compares

Respiration in plantsCompare Photosynthesis and Respiration

In brief Uses a few examples to compare the two processes

Discuss the two processes in detail

Uses related terms and examples to bring out differences clearly between the two processes

CBSE-i Class VII – Biology

Unit: 15Respiration in Organisms

Teacher Student Support Material (TSSM)

Teacher Student Support Material (TSSM)1. Introduction

2. Importance of Respiration3. Breathing and Respiration

a. Breathing Activity 1 Activity 2

b. Breathing rate Activity 3 Activity 4

c. Is breathing and Respiration the same?4. Aerobic and Anaerobic Respirationa. Aerobic

Activity 5b. Anaerobic

Activity 65. Respiratory System of Humansa. Nose

Activity 7 Worksheet 1

b. Wind pipe/Tracheac. Lungsd. Bronchi/Bronchioles6. Mechanism of Breathing

Activity 8 Activity 9 Worksheet 2

a. Journey of Oxygen and Carbon dioxide in body cells

Worksheet 3b. How is Energy consumed?7. Breathing in Other Animals

a. Earthworm b. Cockroach c. Frogd. Fish Worksheet 3

8. Respiration and Exchange of gases in Plants9. Post Content Worksheets

10.Glossary11.E – Resources

RESPIRATION IN ORGANISMS

Introduction

Respiration is a process that involves exchange of oxygen from air with carbon dioxide produced in living organisms. This unit is meant to investigate the importance of respiration for living organisms. Through this unit the learners will be able to correlate the structure of respiratory organs with their functions and also differentiate between breathing and respiration.

This unit will also empower the learners to analyze the link between respiration and the utilization of oxygen to breakdown the assimilated food in order to release energy. It will also include the study of the process of breathing in other organisms such as earthworm, cockroach, and fish. It will provide the learners with enough opportunities/occasions to explore process of respiration and significance of exchange of gases in plants.

Importance of Respiration:

Recall from what have you studied in your previous class that respiration is a characteristic feature of living organisms. It involves two main processes- breathing and energy release. The oxygen taken in during breathing acts on assimilated food in the cells to release energy.

Breathing:

Breathing is the process of inhalation and exhalation of air. Let us carefully observe breathing by performing an activity.

Activity 1:

To experience the process of breathing.

Hold a deflated balloon.

Take a deep breath. Bring

the opening of the balloon

to your mouth and exhale

(blow out) in to the balloon.

We will notice the balloon

gets inflated when we blow

into its mouth.

Thus we observe and experience the process of taking in and

out air during this

activity?

http://www.merckmanuals.com/home/lung_and_airway_disorders/biology_of_the_lungs_and_airways/control_of_breathing.html

Do the following activity, note down your observations and fill up the number of times you breathe. Count one breath as one time inhalation and one time exhalation.(One inhalation + one exhalation = 1 breath)

Activity: 2

Rate of breathing varies with different types of activities in an organism

S no Activity No of times you breathe in a minute.

1. After resting for 10 minutes

2. On the spot jogging for 5 minutes

3. After running for 2 minutes.

4. After cycling for 10 minutes.

5. After climbing stairs for two floors.

Observation: You will notice that the number of times you breathe in a minute varies with the nature of the activities you perform.

Conclusion: We breathe faster when we perform strenuous physical activities.

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Breathing Rate

The number of times a person breathes in a minute is called breathing rate. On an average, an adult human being breathes 15-18 times in a minute. On exercising the breathing rate can go up to 25

times per minute. The rate of breathing is not constant but varies during different activities.

We have learnt in our previous classes that exhaled air contains carbon dioxide. Let us perform an activity to prove the same.

Activity: 3

To prove that the exhaled air contains Carbon dioxide

Think of an experiment you can perform to prove that carbon dioxide is given out as a result of exhalation. You are given the following items. Lime water, a glass, a straw.

The carbon dioxide present in the exhaled air turns the colour of lime water milky. This proves that exhaled air contains carbon dioxide.

you must have noticed someone, cleaning their spectacles by blowing on the

lens and then wiping it? We will notice when we do this, the lens becomes clean.

Let us try to find out the reason for this.

Exhaled Air contains water vapours

Activity 4: (Group activity)

To prove that the exhaled air contains water vapours

Stand in front of a mirror and breathe out. Mirror becomes hazy. This is because there is condensation of water vapours into small droplets of water. This proves that exhaled air contains water vapours.

Is Breathing and Respiration the same?

The term respiration is not the same as breathing. Respiration includes breathing and break down of assimilated food with the help of O2 to release energy. Release of energy from organic compounds in cells is in the form of ATP (energy rich molecules). ATP (Adenosine Tri Phosphate) is the molecule which directly provides energy to various biological reactions that take place in our body. This process takes place in every cell of the body hence is known as Cellular Respiration.

So breathing is a physical process during which there is no oxidation of food. Breathing is a physical process which is simply exchange of gases whereas cellular respiration is a biochemical process which involves breakdown of food (oxidation of food) to release energy.

Therefore we can conclude that what we generally call respiration actually includes both breathing and cellular respiration.

Aerobic and Anaerobic Respiration

Aerobic Respiration:

Observe the demonstration of an experiment showing that living organism breathes.

Activity: 5

Apparatus required: conical flask, bent tube, cork, Vaseline, coloured water, germinating seeds.

Procedure: Take some germinated seeds in a conical flask. Fix the delivery tube bent in “U” shape with a cork to the conical flask. coloured water in a beaker. Put KOH (potassium hydroxide) pellets or

solution in a small test tube and suspend with a thread tied to the rubber stopper in the conical flask as shown in the diagram.

Keep the other end of the delivery tube dipped in coloured water. Make the apparatus air tight by using Vaseline. After some time the water level will rise.

You will observe that there is an increase in the level of coloured water of the delivery tube which is immersed in the beaker containing water.

Inference: This happens because the oxygen which is present in the conical flask is utilized by the germinating seeds and they release carbon dioxide. This carbon dioxide is absorbed by the potassium hydroxide and partial vacuum is created. The coloured water rises to fill

up the vacuum space. Thus this experiment shows that living organisms such as germinating seeds respire.

Suggestion: this experiment may be repeated by replacing germinating seeds with flower buds.

This experiment shows that germinating seeds take in oxygen and give out carbon dioxide.

The process of respiration that utilizes oxygen is known as aerobic respiration.

In the process of aerobic respiration, breakdown of food/glucose takes place in the presence of oxygen releasing CO2, water vapour and energy. Organisms that carry out aerobic respiration are called aerobes.

This process is summed up in a word equation below:

food with the use Oxygen CO2+ H2O + Energy

Anaerobic Respiration:

List living organisms that respire in the absence of oxygen? How do they survive?

There are some organisms like yeast, bacteria and parasites that can survive in the absence of air. They can breakdown glucose to release energy without using oxygen. In this type of breakdown of glucose, in the absence of O2 very little energy is released.

Activity 6: Some organisms respire even in the absence of Oxygen.

Observe the demonstration of an experiment which shows, some

organisms even respire in the absence of Oxygen. Take some sugar solution in a boiling test tube; add some yeast powder to that solution.

Fix the cork. Leave the test tube for two days.

Observation:

lime water turns milky

Smell of alcohol is noticed.

This process of respiration in yeasts can be represented by the following word equation.

Glucose without the use Oxygen Ethyl Alcohol + CO2 + Energy

Conclusion: “Yeasts convert sugar into alcohol”. The yeasts respire in the absence of oxygen.

Organisms which carry out respiration in the absence of oxygen to fulfill their energy needs are called Anaerobes. These organisms have the ability to survive for longer period of time without using oxygen than aerobes.

Industrial application of Yeast.

Yeast produces alcohol and helps in the preparation of bread and cheese.

Thus we can say that the process of respiration that takes place in the absence of oxygen is known as anaerobic respiration.

Observe the following pictures

Why do people get muscle cramps after heavy exercises such as cycling, swimming or jogging for long time?

http://www.pixelatestudio.com/cycling_photos.htm

http://new-york-chiropractor.blogspot.in/2010/12/so-you-were-playing-sports-and-your-leg.html

http://en.topictures.com/physical%20therapist

During heavy exercises, fast running or weight lifting the demand for energy is very high, but the supply of oxygen is very limited and the muscle cells have to respire without adequate supply of oxygen. During this type of respiration, energy released is very less as compared to aerobic respiration.

This can be represented by the following equation.

Glucose in the absence of Oxygen Lactic acid + Energy (in the muscle cells)

The muscle cramps formed after heavy exercises are because of partial breakdown of glucose into Lactic acid which accumulates in

muscles.

Relief from cramps

We can get relief from cramps by hot water bath or massage. This improves the blood circulation and restores the supply of O2

resulting in the complete breakdown of accumulated lactic acid into CO2 and water and thus giving relief from cramps.

Respiratory System in Humans:

Respiratory system facilitates exchange of oxygen and carbon dioxide required by the body. The respiratory system can be divided into three parts. Air passages and tubes include the

nose, wind pipe, bronchi, and bronchioles.

Air pump includes chest cavity containing lungs and diaphragm.

Respiratory surface includes alveolar lining and blood capillaries.(Fig: Respiratory system of human being)

http://people.eku.edu/ritchisong/301notes6.htm

Organs of Respiration in Humans:

By aerobic respiration glucose produces 38 molecules of ATP and by anaerobic respiration the energy yield is 2 molecules of ATP.

The organs of respiration are Nose, wind pipe (trachea), Lungs, bronchi and bronchioles.

Nose: Air normally enters in to lungs through the nose. Hair in the nose traps some of the dust particles that come along with the air. The lining of the nose also produces mucus (a watery liquid) which keeps the air moist and does not allow any dust particles to enter along with air.

The hair and mucus act as filters and allow clean air to pass through the nostrils.

What would happen if we breathe through our mouth? Let us do an activity to understand the significance of correct way of breathing.

Activity 7– Inhaling air through nose and mouth

As the air passes along the nasal passage, the blood vessels beneath the nasal lining release heat. This heat regulates the temperature of the air before it passes in to the lungs. That is why in winters also the air that we breathe out is warm.

Do the following activity to experience inhaling air through nose and mouth and fill up worksheet 7.

Inhaling air through Nose Inhaling air through mouth

http://thebreathingman.wordpress.com/article/nose-breathing-202i29i90v7sn-41/

http://www.rxlist.com/aerospan-hfa-drug/medication-guide.htm

Worksheet 1

Way to breathe

Breathe through the nose and through the mouth each for 5 minutes and note the difference by answering the following questions

in Yes or No as applicable:

Inhaling Inhaling through nose through mouth

1. Does your throat become dry?

2. Do you feel irritation in your throat?

Now what do you advise yourself? You must not breathe through your __________(mouth/nose).

When we breathe through our mouth, there is nothing to stop the dust particles and harmful germs to enter the throat thus causing irritation in the throat.

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Wind pipe / Trachea

From the nose, the air enters pharynx. From the pharynx the air enters into a tube called wind pipe also known as trachea. Trachea is a tube about 12 cm in length and 2.5 cm in diameter in an adult. It might be interesting to note that, whether the air enters through the nose or the mouth, it will pass into the wind pipe through the pharynx.

Lungs

There is a pair of lungs in a human body, present on each side of

the chest cavity. Lungs are the main respiratory organs in our body and are enclosed in chest cavity. This cavity is protected by the bony structures called ribs. At the base (lower end) of the chest cavity there

What is smokers cough?

What will happen in severe bronchitis?

is a large muscular sheet called diaphragm (Observe the diaphragm in the picture given above), which separates the upper part (thoracic cavity) of the body from lower part (abdominal cavity) of the body. The rib bones are attached to the muscles. The muscles of the ribs and diaphragm move during breathing.

http://www.cancer.umn.edu/cancerinfo/NCI/CDR269299.html

Bronchi and Bronchioles:

The wind pipe divides into two smaller tubes called bronchi (bronchus – singular). Each bronchus divides into many smaller bronchioles. Each bronchus enters the lungs and branches into bronchioles. At the end of these bronchioles are air sacs called alveoli.

The air after entering the bronchi, reaches bronchioles and then into alveoli (air sacs). http://www.naturalhealthschool.com/bronchi_trachea.html

From the alveoli the air diffuses into the blood capillaries as they are surrounded by the blood vessels. The carbon dioxide present in the

Some people suffer from asthma. They may be allergic to some foreign materials. These materials cause allergy and the air passages become narrower. This makes breathing very difficult. Such a person has to use inhaler that releases chemicals to make the muscles relax and widen the bronchioles.

http://www.nytimes.com/imagepages/20

blood vessels enters the alveoli and is exhaled through the nostrils along with water vapours.

Mechanism of Breathing:

There are two breathing movements

1) Inhalation

2) Exhalation

InhalationDuring inhalation:

Inter-costal muscles contract Ribs move outwards and

upwards. Diaphragm is pulled

down into a flat position.

Volume of the chest cavity increases

Pressure inside the lungs reduces.

Therefore air rushes into the lungs.

Exhalation:During exhalation: Rib muscles relax Ribs move inwards and downwards. Diaphragm moves up.

Some people suffer from asthma. They may be allergic to some foreign materials. These materials cause allergy and the air passages become narrower. This makes breathing very difficult. Such a person has to use inhaler that releases chemicals to make the muscles relax and widen the bronchioles.

http://www.nytimes.com/imagepages/20

Volume of the chest cavity decreases Pressure inside the lungs increases.Therefore air is pushed out of the lungs.

Watch these Respiration Videos http://www.youtube.com/watch?v=HiT621PrrO0

http://www.youtube.com/watch?v=RfCeiK0xtR0&feature=related http://www.youtube.com/watch?v=12ddbrqpZiQ&feature=related

Activity 8:

Increase in the chest size during inhalation

Instructions:

Measure the size of your chest with a measuring tape and record your observations. Now take a deep breath and hold it. Again measure the size of your chest.

Study the increase in the chest size (in cm) of 4 of your classmates, complete the following table and note the measurements.

Size of the Chest

S.No. Name of the student Normal After a deep Difference

The number of times a person breathes in a minute is called breathing rate.

On an average an adult human being breathes 15 – 18 times in a minute. On

exercising the breathing rate can go up to 25 times per minutes.

Breathing (in cm)

breath (in cm)

in size(in cm)

You may notice the variation in the chest size among the students.

Activity 9: To understand the mechanism of breathing by a simple model.

Take two bell jars. Take a Y shaped glass tube and fix two balloons

on each end. Insert this Y shaped glass tube with balloons in a bell jar or plastic transparent bottle as shown in the diagram.

Tie a thin rubber sheet around the bottom of the bell jar.

hyperphysics.phy-astr.gsu.edu Inhalation Exhalation

This set up is a replica of the human respiratory system. The bell jar is the chest cavity, the balloons are the lungs, and the rubber sheet is the diaphragm. Pull the rubber sheet down, to show that:

i) Space in the jar increases

ii) Balloons get inflated

iii) Air enters the balloons

This is how we inhale.

If we do the reverse we will find:

i) Space in the jar decreases

ii) Balloons get deflated

iii) Air leaves the balloons

This is how we exhale.

Worksheet 2:

Process of inhalation and exhalation

(A) The steps for the process of inhalation are given below. Write the corresponding steps of the process of exhalation on the right hand side.

Process of Inhalation Process of Exhalation

Ribs move outwards and upwards. -------------------------------- Diaphragm is pulled down ------------------------------- Volume of the chest cavity increases ------------------------------- Pressure inside the lungs reduces. -------------------------------- Air enters the lungs ---------------------------------

(B) Observe the diagram given below.

Write the parts of human respiratory system that correspond to the labeled parts: i), ii) & iii).

Corresponding parts of human respiratory system

i)

ii)

iii)

Journey of Oxygen and Carbon Dioxide in Body Cells:

Oxygen from the inhaled air diffuses through the walls of the alveoli into the blood capillaries. This oxygen is carried to all cells of the body, where it breaks down (oxidizes) the assimilated food to release energy.

Carbon dioxide is carried from body cells into the blood capillaries. From the blood capillaries it diffuses into alveoli. It is then pushed out through bronchioles, bronchi, and exhaled through the nostrils. Blood moves into the capillaries very quickly.

web.med.unsw.edu.au

Work sheet 3:

Trace the path of oxygen and carbon dioxide

Trace the path of oxygen and carbon dioxide in the table given below.

Write the names in correct sequence of the two paths. Use red colour for tracing path of oxygen and blue colour for carbon dioxide. Choose the appropriate words from the list provided below, the first step of each path is done for you.

Path of oxygen Path of carbon dioxide

1 Nose 1. Body cells

2 -------------- 2 -------------

3---------------- 3 ----------------

4 ---------------- 4 ----------------

5 ----------------- 5 ---------------

6 ----------------- 6 ----------------

7 ---------------- 7 -----------------

----------------------------------------------------------------------------------

How is Energy Produced?

trachea, alveoli, body cells, bronchioles, bronchi, blood capillaries, nose

We have studied that the digested food substances enter the cells of the body through the blood. The oxygen of the air enters the blood from alveoli.

The blood carries the oxygen to the cells of the body during its

circulation. The oxygen acts upon the food present in the cells of the body to produce energy and release carbon dioxide.

The change can be summarized as:

Food + oxygen CO2(carbon dioxide) + Energy + Water vapours

Since the energy is released in the cells, the process is known as cellular respiration.

Cellular Respiration is a Biochemical Process.

Breathing in other animals:

We know that animals obtain energy by the oxidation of assimilated food. We have seen that respiration needs continuous supply of oxygen to break down the food and carbon dioxide is released during respiration. Let us see how the exchange of gases takes place in some other animals.

Earthworm:

The earthworms live in damp soil. Gaseous exchange takes place through their moist skin. In these earthworms, the thin and moist skin is richly supplied with blood vessels (capillaries) which absorb oxygen from the atmosphere and

release carbon dioxide. Earthworms breathe through their moist skin

Insects:

Air reaches various parts of the body of an insect through an elaborate system of branching tubes called tracheae. The tracheae open outside through holes called spiracles. Most of the tracheal tubes run along and across the body and divides into smaller called tracheoles.

Oxygen enters tracheal system through the spiracles and diffuses into the body cells. Carbon dioxide diffuses out of the body cells into trac Larva of an insect

heal system and is carried out of the body through the spiracles.

http://www.entomology.umn.edu/museum/projects/Interactive_Keys/Intro_tutorial/GLOSSARY/Spiracles.html

Frog:

Frogs can live both in water and on land, therefore, they can breathe both on land and in water. They have a pair of lungs and a large opening of the mouth (buccal cavity) to enable them to breathe on land. They have a moist, slimy skin to enable them to breathe in water. Since they live in amphibious habitat they are known as amphibians.

Fish

Fishes absorb dissolved oxygen present in water by gills. Gills are projections of the skin and are richly supplied with blood vessels for exchange of gases. A fish gulps water through the mouth and forces it between the gills on each side of its neck. As water flows across the gills, the oxygen in it gets diffused into the blood stream. At the same time carbon dioxide in the blood stream diffuses into the water.

Organs of breathing of different animals help them to breathe in their specific habitats.

So we notice animals living in soil such as earthworm breathes through moist skin, land animals such as insects breathe through spiracles and aquatic animals such as fish breathe through gills. Animals such as frogs that can live on land and in water have lungs to breathe while on land and moist skin to breathe while in water.

We can conclude that animals of different habitats have different organs of breathing.

Respiration in Plants:

Plants do not make breathing movements to exchange oxygen and carbon dioxide. They rely on the process of diffusion through which

the gases move in and out of their cells and their body.

http://evolution.berkeley.edu/evolibrary/article/mcelwain_02

Exchange of gases in Plants

Like all other living organisms, plants also respire for their survival for which they take in oxygen from the air and give out carbon dioxide. Plants do not have any organ system or organs for breathing. It is interesting to note that in plants exchange of gases takes place by simple diffusion directly into each cell through the openings present in epidermis called stomata.

Even the stems have openings called lenticels that help in the exchange of gases. Lenticels are present in older roots also. These pores on leaves, stems and roots allow oxygen, carbon dioxide and water vapours to come in and out of the plant body. Leaves and stems

exchange gases from the air they are exposed to whereas roots which grow under the soil take up air from the air spaces present between soil particles.

http://preuniversity.grkraj.org/html/4_PLANT_AND_WATER_RELATIONSHIP.htm

Recall that during photosynthesis, plants take in carbon dioxide and give out oxygen. We also know this process takes place only in the presence of light.

Now we also know living organisms, including plants, take in oxygen and give out carbon dioxide during respiration. This process takes place throughout the life of the organisms.

We can conclude that exchange of gases through the stomatal pores is the due to respiration and photosynthesis during the day, whereas at night, it is only due to respiration.

So we have learnt that respiration is an important biological process in all living organisms. It is through respiration that the living organisms get the much needed energy for their survival.

What would happen if a potted plant is overwatered?

POST CONTENT WORKSHEET 1 1) List the similarities and differences between aerobic and anaerobic respiration.

2) Define breathing rate?

3) Why do we sneeze when we inhale dust?

4) Define the terms inhalation and exhalation.

5) Why do we breathe faster after running?

6) Why do we yawn when we are sleepy?

7) Give simple word equations for the following types of respiration:-

a) aerobic respiration

b) anaerobic respiration in yeast

c) anaerobic respiration in the muscles of man.

8) Why do we feel hungry after a vigorous exercise session?

9) Draw and label the parts of the human respiratory system.

10) Describe in brief the mechanism of breathing.

11) Depict mechanism of breathing diagrammatically.

12) Give an experiment to prove that we exhale air with CO2 and water vapours.

13) Complete the statements given below by choosing the most appropriate word from the list given below:

a) ------------------is located at the base of the chest cavity.

b) During heavy exercises, we get cramps in the legs due to the

accumulation of -------.

c) Normal range of breathing rate in a healthy adult at rest is---------- per minute.

d) During inhalation, the ribs move --------- and --------------.

e) The size of the chest cavity ------------- during inhalation.

14) What is the full form of ATP?

Diaphragm, Ribs, carbon dioxide, inwards, outwards, upwards, downwards, 15-18 times per minute, 40 times per minute, increases, decreases

POST CONTENT WORKSHEET 2

1) State if the following statements are true or false (T/F):-

a) Plants carry out respiration only during the day. (T/F)

b) Photosynthesis takes place only during the day. (T/F)

c) Frogs breathe both through lungs and skin. (T/F)

d) Cockroaches respire through lungs (T/F)

2) Explain briefly how insects respire? .

3) Earthworms have moist skin. Why?

4) How do gills help fishes to breathe under water? Also draw diagram

to show gills in a fish.

5) What are stomata? Where would you look for them?

6) Explain how do roots breathe?

7) What will happen if a potted plant is flooded with water?

8) Why do we use flower bud/ germinating seeds in the experiment

which shows respiration occurs in living organisms?

Glossary

Toxic – poisonous and harmful to people

Diffusion – random movement of molecules (liquid or gas) resulting in mixing in another substance

ATP - Energy rich molecule (full form - Adenosine Tri Phosphate) in the cells that lets the energy go from it for chemical reactions

Biochemical - relating to the chemical substances and processes in living organisms

Vacuum - space completely empty of all substances including air or gases

Inhalation - taking in (inhale) air during breathing.

Exhalation - giving out (exhale) air during breathing

Metabolism - biochemical processes in cells necessary for life, all the chemical processes by which cells produce the energy and substances necessary for life

Fermentation - a chemical change due to the action of Yeast or Bacteria often changing sugar to alcohol

Anaerobic - a process or a happening that does not need oxygen.

Aerobic respiration - the process of respiration that requires oxygen in order to release energy by the breakdown of food

Alveoli – The air sacs through which the air diffuses into and out of blood capillaries from bronchioles located in the lungs.

E – Resources

http://www.getbodysmart.com/ap/respiratorysystem/zonesdivisions/tutorial.html

http://www.getbodysmart.com/ap/respiratorysystem/menu/menu.html

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/ animation gas_exchange_during_respiration.html Gas Exchange Animation

http://www.youtube.com/watch?v=HiT621PrrO0 Respiration Video

http://www.youtube.com/watch?v=RfCeiK0xtR0&feature=related Respiration Video

http://www.youtube.com/watch?v=12ddbrqpZiQ&feature=related Respiration Video http://www.youtube.com/watch?v=Mf8xTqfspp4 Diaphragmatic breathing animation

http://www.daviddarling.info/encyclopedia/Respiratory_system.html Gas Exchange in Lungs

http://www.health.com/health/library/mdp/0,,tp10237,00.html Gas Exchange in Lungs

http://www.tutorvista.com/content/biology/biology-iv/respiration-animals/breathing-mechanism.php Experiment on Breathing Mechanism

http://www.ischool.zm/es/STUDY%202.html Experiment on Breathing Mechanism

http://www.merckmanuals.com/home/lung_and_airway_disorders/biology_of_the_lungs_and_airways/control_of_breathing.html Diaphragm movements with breathing

http://www.pixelatestudio.com/cycling_photos.htm Cyclist

http://en.topictures.com/physical%20therapist Muscular Pain in legs

http://thebreathingman.wordpress.com/article/nose-breathing-202i29i90v7sn-41/ Breathing from Nose

http://www.rxlist.com/aerospan-hfa-drug/medication-guide.htm

Breathing from Mouth

http://people.eku.edu/ritchisong/301notes6.htm Respiratory System

http://www.naturalhealthschool.com/bronchi_trachea.html Tracheahttp://www.cancer.umn.edu/cancerinfo/NCI/CDR269299.htm Diaphragm

http://www.youtube.com/watch?v=HiT621PrrO0 Respiration Video

http://www.youtube.com/watch?v=RfCeiK0xtR0&feature=related Respiration Video

http://www.youtube.com/watch?v=12ddbrqpZiQ&feature=related Respiration Video

http://preuniversity.grkraj.org/html/4_PLANT_AND_WATER_RELATIONSHIP.html Absorption by roots

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