Class 7 Biology - Respiration In Organisms

Differentiate between aerobic and anaerobic respiration.

Aerobic respiration	Anaerobic respiration
It refers to the breakdown of food in the presence of oxygen.	It is the breakdown of food in absence of oxygen.
End products produced are carbon dioxide and water.	End products generated are lactic acid and alcohol.
A long process.	Comparatively faster process.
A large amount of energy is produced.	A comparatively small amount of energy is produced.
Occurs in all plants and animals.	Observed in yeast, human muscle cells, etc.

What is the site of gaseous exchange in an insect?

$$\textbf{Solution}$$

$$\bullet$$The gaseous exchange process in the insects occurs through a network of tubes which is known as tracheal system.

$$\bullet$$  Tracheal respiratory system in which the oxygen and the carbon dioxide primarily travels through air filled tubes called trachea.
$$\bullet$$  The trachea is filled with the most mucous membrane layer which is composed of cells that contains hair like to sections cilia.
$$\bullet$$  The oxygen rich air enters into the spiracles which are connected to the network of tubes. The oxygen diffuses into the cells of the body and then releases carbon dioxide which follows the reverse path in which the carbon dioxide first moves from the cells of the body into the trachea and then leaves through the spiracles.

Sugar is converted into alcohol.
(a) From the above statement what kind of process takes place?
(b) Which micro-organism is involved?

(a) Anaerobic respiration

(b) Yeast is involved in the reaction. These are single-celled fungi which can perform anaerobic, alcoholic fermentation. They are used for the production of alcohol on a commercial scale.

Give the name of respiratory organ of Fish, Earthworm, Cockroach and Human(man).

Sr. No.	Name of animal	Respiratory organ
1	Fish	Gills
2	Earthworm	Skin
3	Cockroach	Trachea
4	Human	Lungs

What is breathing?

$$\textbf{Solution:}$$

$$\bullet$$ Breathing is the process of inhaling air into the lungs and then exhaling it out of the lungs to facilitate gas exchange with the internal environment, primarily by bringing in oxygen and flushing out carbon dioxide.

$$\bullet$$ Breathing occurs involuntarily, i.e., it is not under our control.

$$\bullet$$ A normal adult human breathes 12-16 times/min in which inspiration lasts for about 2 seconds and expiration lasts for about 3 seconds and an infant breathes about 44 times/min.

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) Skeleton 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.

(i) The air tubes of insects - TRACHEA -Insects, and some other invertebrates, exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. Tracheae open to the outside through small holes called spiracles.
(ii) Skeleton structures surrounding the chest cavity - RIBS - Ribs and sternum together form a rib cage that surrounds the chest cavity.
(iii) The muscular floor of the chest cavity -DIAPHRAGM-Diaphragm is the muscular structure, located throughout the bottom of the thoracic cavity. It separates the abdominal cavity from the thoracic cavity which contains the heart and the lungs.
(iv) Tiny pores on the surface of leaf - STOMATA -The tiny pores on the lower surface of a leaf is known as Stoma in singular form & in plural form Stomata.
(v) Small openings on the sides of the body of an insect -SPIRACLES --Insects, and some other invertebrates, exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. Tracheae open to the outside through small holes called spiracles.
(vi) The respiratory organs of human beings - LUNGS -The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). they are primary organs of the respiratory system in humans.
(vii) The openings through which we inhale - NOSTRILS -Nostrils are two external openings of the nasal cavity invertebrates that admit air to the lungs and smells to the olfactory nerves. Hence nostrils are the openings through which we inhale.
(viii) An anaerobic organism -YEAST-In the absence of oxygen yeast performs anaerobic respiration.
(ix) An organism with a tracheal system -ANT -Ants have an interesting respiratory system consisting of spiracles (tiny openings located on the outside of the exoskeleton that allows the transport of oxygen into and carbon dioxide out of ) and trachea (the respiratory ducts throughout the body).

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Define cellular respiration.

Explanation -

Cellular respiration is a series of metabolic processes taking place in a cell . It converts chemical energy from nutrients into adenosine triphosphate(ATP), and then release waste products.

Which type of respiration results in the formation of water as a byproduct?

Water is formed along with carbon dioxide and energy during aerobic respiration when Glucose breaks down. This process takes place only in the presence of oxygen and is called aerobic respiration.

Differentiate between respiration and breathing.

The process by which foodstuffs are oxidized in cells to release energy for utilization in the body is known as respiration.

The process of taking fresh air from the atmosphere into lungs and expelling out the foul air from lungs to the exterior is known as breathing.

Do plants breathe?

Plants are living organisms and hence, they breathe just like humans and other animals. They take in oxygen and release out carbon dioxide. Respiration should not be confused with photosynthesis. Plants take in very less amount of oxygen for respiration as compared to the amount they release during photosynthesis.

Name the body structure concerned with the given functional activity:
Increases the volume of the chest cavity in a lengthwise direction.

The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily.
Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.
During exhalation, the diaphragm relaxes and returns to its dome-like shape forcing the air out of the lungs.
Thus the diaphragm contracts to increase the thoracic cavity lengthwise.

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Name the animals that respire through gills, lung and skin.

Gills are the respiratory organs in aquatic organisms such as fishes. Gills help in the exchange of respiratory gases by absorbing dissolved oxygen from the water and releasing carbon dioxide in the water.
Lungs are the respiratory organs of many land animals such as lizards, dogs, frogs etc. The exchange of respiratory gases take place in the alveoli of lungs.
Skin is the respiratory organ in earthworm and amphibians such as frog. The respiratory gases diffuse through the surface of skin in such animals. Frog can respire by both through lungs and skin.

State one function of each of the following:
Diaphragm

$$\textbf{Solution:}$$

$$\bullet$$ The diaphragm is a muscular wall that separates the thorax from the abdomen and serves as the foundation of the chest cavity.

$$\bullet$$ It flattens and expands the chest cavity during inhalation to allow air to enter the lungs, and it relaxes during exhale.

What are the functions of the following in breathing?
Ribs

When we breathe in, or inhale, the diaphragm contracts (tightens) and moves downward. This increases the space in your chest cavity, into which your lungs expand. The ribs move upward and outward during inhalation and downward and inward during exhalation so as to increase and decrease the volume of the chest cavity respectively.

Describe the process of respiration in fish.

Respiration in fish takes with the help of gills. Most fish possess gills on either side of their head. Gills are tissues made up of feathery structures called gill filaments that provide a large surface area for gas exchange. Fish take in oxygen-rich water through their mouths and pump it over their gills.

Describe the process of respiration in the following part of a plant.
Root.

Like all other living cells of the plants, the root cells also need oxygen to generate energy. Roots take up air from the air spaces present between the soil particles.

Define breathing.

Breathing means taking in air rich in oxygen and giving out air rich in carbon dioxide with the help of respiratory organs. The taking in of air rich in oxygen into the body is called inhalation and giving out of air rich in carbon dioxide is known as exhalation.

What is normal breathing rate in an adult man at rest?

In an adult man at rest the normal breathing rate is $$12$$ to $$15$$ times per minute.

Differentiate between the following pair based on the aspect given in the bracket.
Aerobic and anaerobic respiration (end products of the process):

Aerobic respiration - Carbon dioxide, water, and energy
Anaerobic respiration :

Alcohol, Carbon dioxide, and Energy - in yeasts
Lactic acid and energy in muscle cells

Give reason
It is different to demonstrate respiration in plants.

The respiration in plants differs from that of animals. In plants, each part like leaves and roots can independently take in oxygen from air and give out carbon dioxide.

In leaves, oxygen enters into the leaf through stomata and reaches the cells by diffusion. The carbon dioxide is released out from the leaf into the air through the stomata.

In roots, the air enters by the spaces between the soil particles. Root hairs are present in the soil particles. Oxygen diffuses into the root hairs and reach all the cells of the root for respiration. Carbon dioxide produced is expelled through the same root hair diffusion.

State the three common features of all the respiratory organs like Skin, Gills and Lungs.

The three common features of all the respiratory organs like Skin, Gills, and Lungs are

All the respiratory organs have large surface areas for exchange of gases.
All the respiratory organs are thin-walled for easy diffusion of gases and substances.
All the respiratory organs (like the skin, lungs, gills) have a rich supply of blood for transporting respiratory gases.

Fill in the blank and explain the statement.

Our muscle cells perform__________ type of respiration during exercise.

Our muscle cells perform anaerobic type of respiration during exercise.

During exercise, our body requires a lot of energy. Due to limited amount of oxygen intake, the muscle cells perform anaerobic respiration.

What is respiration? How is it different from breathing?

Explanation:

Respiration is the process of breaking down the glucose molecule, and during this breakdown, it should produce energy in the form of ATP.
it occurs at the cellular level whereas breathing occurs in the lungs.
The uptake of oxygen from lungs is forwarded to tissues and at the same time elimination of CO2 from the tissues.
Breathing is the normal inhalation or exhalation of gases in the atmosphere.

Fill in the blank with a suitable word.

Cockroaches breathe with the help of air tubes called _______.

Cockroaches breathe with the help of air tubes called tracheae.

The respiratory organ of the cockroach is referred to as the tracheae. The trachea is a dense array of a network of air tubes found in the internal system. Oxygen-rich air enters the body of the cockroach via spiracles into the tracheal tubes and diffuses into various tissues and cells of the body directly.

Which respiratory structure is present at the floor of chest cavity?

Diaphragm is a dome shaped respiratory muscle present at the floor of the thoracic cavity.

Under what condition lactic acid is produced in the muscle cells?

Under anaerobic respiration condition, lactic acid is produced in the muscle cells. E.g. Running for a long duration.

What helps them to breath?
A fish

Gills help in breathing in fishes.

Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?

Explanation:

Aquatic organisms breathe faster as compared to terrestrial organisms. This is because the amount of O2 present in the water is very less as compared to the amount of O2 present in the air. That's why aquatic organisms to get more O2, they need to breath at a high rate generally.

Also, due to the low oxygen in water, aquatic animals have to breath rapidly to take in sufficient oxygen. Thus, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.

Name the organs of respiration in the following organisms:
(a) Flatworm
(b) Birds
(c) Frog
(d) Cockroach

The organs of respiration are

(a) Flatworm - Body surface
(b) Birds - Lungs
(c) Frog - Lungs and skin
(d)Cockroach - Trachea

Where is the diaphragm found?

The diaphragm is found at the floor of the chest cavity and roof of the abdominal cavity.

(a) What is respiration?
(b) Draw a labelled diagram of cross section of leaf.
(c) Explain the transportation of food and other substances in plants.

(a) The respiration refers to catabolic process of breakdown of reduced substrates. The respiration can be aerobic or anaerobic.

They consist of sieve cell and sieve tube. They conduct carbohydrates (sucrose mainly), amino acids, hormones.

The transportation of food in phloem is an active process achieved by utilizing energy from ATP which helps in creating osmotic pressure that transports food against the gradient from the area of high concentration to low concentration.

Plants produce carbohydrates (sugars) in their leaves by photosynthesis, which is further conducted to different parts of the plant for proper functioning.

For this reason, nutrients are translocated from sources (regions of excess carbohydrates, primarily mature leaves) to sinks (regions where the carbohydrate is needed).

Some important sinks are roots, flowers, fruits, stems, and developing leaves.

A student has set up an apparatus to show that "$$CO_2$$ is released during respiration". After about 1 hour he observes no change in the water level in the delivery tube. Write two possible reasons for failure of the experiment.

The reason would be for the failure of experiment are as follows:

The huge rise in the quantity of water shows that CO2 is generated by fully germinating seeds during the respiration process.
In fact, the germinating seeds actually respire as well as produce CO2.
It is absorbed by the KOH solution.
It creates the vacuum in conical flask.
The overall air content present in bent glass tube fully moves into conical flask.
It pulls the water content in bend tube more.

STRUCTURED/APPLICATION/SKILL TYPE
Given below is an overall chemical reaction of a certain process
C$$_{6}$$H$$_{12}$$O$$_{6}$$ $$ \rightarrow \, lactic \, acid \, + energy$$

Name the process.

The process is Anaerobic respiration or Fermentation. It takes place in the absence of oxygen and lactic acid is produced as a by-product.

___________ gas is evolved during respiration in plant.

$$\textbf{Solution}$$ Carbon Dioxide

$$\bullet$$ The plant produces its food with the help of photosynthesis , in which the plant takes of the atmospheric carbon dioxide and produces sugar and oxygen.

$$\bullet$$ The respiration process in the plant is just opposite of photosynthesis.
$$\bullet$$ The process of respiration occurs in the leaves stems and roots of the plant. During this process the glucose breaks down in the presence of oxygen to release carbon dioxide and water along with energy in the form of ATP.

$$\bullet$$ So, during the process of respiration in the plant carbon dioxide gas is evolved.

Explain respiration in different parts of plant using diagram.

Respiration takes place in all parts of the plants. The gaseous exchange happens through diffusion as in roots, through specialized pores like stomata and lenticels in leaves and stem respectively and also through pores in fruits.
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Respiration In Organisms - Class 7 Biology - Extra Questions

Differentiate between aerobic and anaerobic respiration.

What is the site of gaseous exchange in an insect?

Sugar is converted into alcohol.
(a) From the above statement what kind of process takes place?
(b) Which micro-organism is involved?