Respiration in Organisms
Science Class Seven
Summary: Quick Reading
Why do we respire?
All living things need energy to be live. All works, such as walking, speaking, running, eating, etc. need energy. To get energy we respire.
Respiration : Definition of Respiration
Breaking down of glucose which we get from food to give energy is called Respiration.
The process of producing energy by burning food in our body is called respiration.
Cellular Respiration
The burning of glucose takes place in the cells of body, so the respiration is called the Cellular Respiration.
Breathing
Burning of food to get energy needs oxygen. We get this oxygen from air by a process called breathing.
Taking oxygen in and expelling carbon dioxide out using our nostrils is called Breathing.
The whole process of breathing is performed collectively by nostrils and lungs, that is by respiratory system.
Oxidation of food
The burning of food in our body using oxygen is called oxidation of food or oxidization of food. This is the process which is known as Respiration.
This means respiration is nothing but oxidation of food in which energy is released. This released energy is consumed by body of living organisms to perform works.
How do we get energy in Respiration?
Food we get is converted into glucose by the process of digestion. We take oxygen in the course of breathing. This glucose is broken down into carbon dioxide and water and release energy using oxygen.
The Reaction takes place in the Respiration
Glucose + Oxygen ⇒ Carbon Dioxide + Water + Energy
C6H12O6 (Glucose) + 6O2 (Oxygen) ⇒ + 6CO2 (Carbon dioxide) + 6H2O (Water) + Energy
Types of Respiration
There are two types of RESPIRATION. First Aerobic Respiration and second Anaerobic Respiration.
(a) Aerobic Respiration
Respiration needs oxygen to burn food in cells to release energy. Thus, respiration takes place in the presence of oxygen to release energy is called Aerobic Respiration.
In Aerobic Respiration carbon dioxide and water are formed as by products along with release of energy.
Glucose + Oxygen ⇒ Carbon Dioxide + Water + Energy
Aerobic respiration takes place in human and other complex animals.
(b) Anaerobic Respiration
Respiration that takes place in the absence of oxygen to release energy is called Anaerobic Respiration.
Alcohol (Ethyl Alcohol) or Lactic acid and Carbon dioxide are formed as by products in the process of Anaerobic Respiration.
Anaerobic Respiration in microorganisms
Microorganisms such as cockroach, earthworms, and most of the other insects etc. respire in the absence of oxygen to release energy. Such respiration is called Anaerobic Respiration.
In the course of anaerobic respiration alcohol and carbon dioxide are formed as by products along with release of energy.
Glucose (burning of glucose in absence of oxygen) ⇒ Alcohol + Carbon Dioxide + Energy
Respiratory system of these microorganisms are developed in such a fashion that they respire effectively in the absence of oxygen.
Because microorganisms respire in the absence of oxygen, that is in microorganisms' energy is released in the course of anaerobic respiration, so microorganisms are called Anaerobes also.
Anaerobic Respiration in Human
Sometimes during heavy physical works, such as fast running, heavy exercise, etc. human body needs more energy. And in the absence of supply of sufficient oxygen, muscle cells start respiration in the absence of oxygen to fulfill the extra needs of energy.
In this anaerobic respiration lactic acid and carbon dioxide are formed as by products along with release of energy.
Glucose (burning of glucose in the absence of oxygen) ⇒ Lactic Acid + Carbon dioxide + Energy
Cramp in the muscle cells in human due to Anaerobic Respiration
In anaerobic respiration lactic acid is formed in the muscle cells to release energy. Because of formation of lactic acid, human experience cramp in muscle cells. This happens generally after heavy physical works.
The cramp goes after taking a hot bath or message. By taking hot bath and/or message lactic acid is broken down into alcohol and water.
"An + aerobic" means "in absence of oxygen." Here "An" is a negative prefix which means "no".
Uses of Anaerobic Respiration
In the case of anaerobic respiration in microorganisms, ethyl alcohol is produced as the end product. This ethyl alcohol which is formed in anaerobic respiration in the respiration by microorganisms is used in many products.
Example: In the fermentation of batter, in the making of wine, in making of vinegar, in dairy such as in the making of curd, cheese, etc.
Respiration in Human
There are two sets of processes involved in the respiration in human. First breaking down of glucose to release energy, and second exchanges of gas.
In the first process oxygen taken in is used to burn glucose in cells to release energy along with carbon dioxide and water as by products.
In the second process, carbon dioxide along with water as moisture are expelled out in the breathing out through nostrils.
Breathing
For respiration we breath. Breathing is performed in two sets of processes. First is breathing in and second is breathing out.
Breathing In
We breath in air rich in oxygen. This oxygen is sent to blood by our respiratory system. The oxygen carries by blood to cells where it is used in burning of food to release energy.
Breathing out
We breathe out carbon dioxide along with water as moisture.
The carbon dioxide and water are formed as by products in the course of respiration along with releasing energy. The carbon dioxide is so formed is expelled out while breathing out.
The taking oxygen in and expelling out carbon dioxide is called breathing. We take air in and give air out through our nostrils. All living organism need breathing to keep them survive. It continues till life, without breathing none can survive.
Inhalation and Exhalation
Breathing in is known as Inhalation or Inspiration also.
Breathing out is known as Exhalation or Expiration also.
Breathing rate
The number times a person breathes in one minute is called the breathing rate. One breath means one inhalation and one exhalation.
Breathing Faster
We need extra energy while performing heavy physical works, such as running, doing exercise, fast cycling, fast walking, etc. This requires more oxygen to release extra energy in the course of respiration which is fulfilled by faster breathing.
Normal Breathing Rate
On an average, an adult human being at rest breathes in and out 15–18 times in a minute.
During heavy physical works, we breathe faster and the breathing rate can increase up to 25 times per minute.
How Do We Breathe?
There is a dedicated respiratory system found in animals for respiration. We breathe through our respiratory system.
Human Respiratory System
Our respiratory system comprises of nostrils, pharynx, larynx, trachea, bronchi and lungs.
Breathing starts from nostrils. From nostrils we take air rich in oxygen which goes to lungs passes through pharynx, larynx, tracheal and bronchi.
In the lung oxygen mixes with blood and goes to all parts of body.
In the respiration, carbon dioxide and water are formed as by products along with release of energy. Blood carries this carbon dioxide to the lungs from where it goes to nostrils via bronchi and trachea to the nostrils and expelled out, which is called breathing out.
Diaphragm
The diaphragm is like a big membrane. Diaphragm separates thoracic cavity from abdominal cavity. Thoracic cavity is the chamber which contains heart and lungs. The chamber which contains stomach, intestines, etc. is called the abdominal cavity.
Process of Breathing
Diaphragm helps in breathing by moving up and down. By moving down lungs expand and air filled inside it, and by moving up lungs contract and carbon dioxide expel out.
Breathing in other animals
In unicellular and very small multicellular animals, respiration take place through the process of diffusion. For example, earthworms, jellyfish, sponges, etc., use diffusion and osmosis for the exchanges of gas.
Respiration in Cockroach
Cockroach respires through a network of air canals present in its body by the process of diffusion. There are small holes opening present near the head of cockroach using which it takes air in and out. These small holes are called spiracles. And the network of air canal present in the body is called trachea. The trachea and spiracles are not found in animals other than insects.
Respiration in Earthworm
Earthworms respire through their moist and slimy skin by the process of diffusion.
Respiration in Frogs
Frogs are called amphibian as they can survive on land as well as in water. Amphibian means the animal that can live in water and on land both with equal ease. Frog has lungs and moist and slimy skin both. Frogs can respire through their skin as well as through their lungs. On land frogs respire through their lungs. While in the water they respire through their skin by the process of osmosis.
The movement of a material through a membrane is called osmosis. Osmosis takes place in liquid medium.
BREATHING UNDER WATER
Respiration in Fish
Fish live in water and breathe through their gills. Gills are present both sides near the head of fish. Fish take oxygen in dissolved in water through their gills.
Respiration in plants
Plants take oxygen in and release carbon dioxide out. A plant respires through its leaves and branches. There are many porous present on every parts of the plant. Gases exchange through these minute porous layers. Leaves of a plant have small pores called stomata. Plants respire through these stomata. Exchange of gases in plants takes place through diffusion.
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