Tag: Breathing

Introduction

All of the body’s cells require energy to support various metabolic processes, thus every living thing engages in cellular respiration to release energy, which is then stored in the form of ATP. After ingestion, food is transported into the stomach via the oesophagus, where stomach acids and enzymes break it down into several smaller bits, including glucose. Since glucose is the most prevalent monosaccharide and the first substrate for the metabolism of carbohydrates, where it is broken down to release energy, glucose and ATP are the molecules that carry the energy.

Definition of Cellular Respiration

All plant and animal cells produce energy through a process called cellular respiration (excluding RBCs). Food glucose is broken down into carbon dioxide, water, and energy with or without oxygen throughout this process. As a result, it liberates ATP and releases carbon dioxide as a waste product (adenosine triphosphate).

Difference between Respiration and Breathing

Respiration	Breathing
Respiration is the physiological process of breathing in and breathing out. Energy is released from cells during the chemical breakdown of food-derived glucose.	Breathing is the movement of oxygen into the body from the outside environment and the release of carbon dioxide from the lungs into the outside environment.
It is categorised into cellular respiration and physiological respiration.	Since breathing is a form of respiration, it is often referred to as physiological respiration.
In cells, and notably in cellular organelles like the cytosol and mitochondria, cellular respiration takes place.	It takes place in the lungs.
There is the involvement of enzymes.	There is no involvement of enzymes.
It produces ATP that is converted into energy.	It does not produce energy.

Glycolysis

• One glucose molecule is broken down into two pyruvate molecules in this process, which also results in the creation of ATP. 
• Every cell in the body contains it in the cytoplasm. Hexokinase enzyme converts glucose to glucose-6-phosphate.
• By using phospho-hexose isomerase, which are isomers of one another, glucose 6-phosphate is converted to fructose 6-phosphate. 
• By phosphorylating fructose 6-phosphate, phosphofructokinase catalyzes the irreversible conversion of fructose 6-phosphate to fructose 1,6-bisphosphate.
• Aldolase catalyzes the breakdown of fructose 1,6 bisphosphate into glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.
• The reversible interconversion of glyceraldehyde 3-phosphate and dihydroxyacetone phosphate is carried out by phosphotriose isomerase.
• Glyceraldehyde 3-phosphate is converted to 1,3-bisphosphoglycerate by glyceraldehyde 3-phosphate dehydrogenase. 
• In this stage, \(NA{D^ + }\) is converted to \(NAD{H^ + }\) and \({H^ + }\), which adds a phosphate group to glyceraldehyde 3-phosphate. With the creation of ATP, the enzyme phosphoglycerate kinase converts 1,3-bisphosphoglycerate into 3-phosphoglycerate.
• Phosphoglycerate mutase converts 3-phosphoglycerate into 2-phosphoglycerate, and these two substances are isomers. 
• Enolase transforms 2-phosphoglycerate into the highly energetic molecule phosphoenolpyruvate once water is removed. 
• In the presence of pyruvate kinase, phosphoenol pyruvate is transformed into pyruvate along with the creation of ATP.       
•  

Generation of ATP: Two pyruvates, two NADH, and two ATP molecules are the final products of glycolysis. Due to the conversion of glucose into two pyruvates, 8 ATP molecules are produced.

Krebs Cycle

Acetyl CoA is converted into carbon dioxide and water by some chemical processes called Krebs cycle.

• Pyruvate is converted to acetyl CoA through oxidative decarboxylation by pyruvate dehydrogenase. 
• The elimination of carboxylate groups to create carbon dioxide is known as oxidative decarboxylation. Acetyl CoA and oxaloacetate are condensed by citrate synthase. 
• Aconitase converts citrate into isocitrate.
• Isocitrate dehydrogenase uses oxidative decarboxylation to change the isocitrate to oxalosuccinate, which is then transformed into -ketoglutarate. 
• By removing the carboxylate group from ketoglutarate and generating carbon dioxide, the enzyme ketoglutarate dehydrogenase transforms ketoglutarate to succinyl CoA. 
• Succinate thiokinase causes succinyl CoA to be converted to succinate. A phosphorylated group is added to GDP to create GTP, which is then converted into ATP by a protein called nucleoside diphosphate kinase. 
• By catalysing the conversion of succinate to fumarate and producing \(FAD{H_2}\), succinate dehydrogenase.
• By including water, fumarase catalyses the conversion of fumarate to malate.
• Malate dehydrogenase converts malate to oxaloacetate and generates NADH in the process. 
• The cycle is maintained by mixing the oxaloacetate with more acetyl CoA molecules.
• 

Generation of ATP: In the Krebs cycle, 12 ATP is produced as a result of the production of 2 \(C{O_2}\), 3 NADH, and 1\(FAD{H_2}\).

Electron Transport Chain or Terminal Oxidation or Oxidative Phosphorylation

The proton gradient created by the electron transport chain (ETC), a chain of proteins that transports electrons through the mitochondrial membrane, powers ATP generation. A series of ETC enzyme complexes: 

• NADH-ubiquinone reductase – Complex I
• Succinate CoQ reductase – Complex II
• Ubiquinone-cytochrome c oxidoreductase – Complex III
• Cytochrome oxidase – Complex IV 
• ATP synthase – Complex V 

Through electron carriers such as flavoproteins, cytochromes, coenzyme Q, nicotinamide nucleotides, and iron-sulfur proteins, these catalyze the transport of electrons.

Since energy is lost during the passage of electrons through ETC, the ATP synthase complex uses the energy to produce ATP from ADP, a procedure known as oxidative phosphorylation. 32 ATP molecules are generated during oxidative phosphorylation and ETC.

Differences between Glycolysis and Krebs Cycle

Glycolysis	Krebs cycle
It involves both aerobic and anaerobic respiration.	It involves only aerobic respiration.
The substrate substance is glucose.	The substrate material is acetylAcetyl CoA.
Glycolysis takes place in the cytoplasm.	The KrebsKrebs cycle takes place in the mitochondria.
It consumes two molecules of ATP.	It does not consume ATP.
Carbon dioxide is released in glycolysis.	Carbon dioxide is not released in the Krebs cycle.
It is a linear enzymatic reaction.	It is a non-linear pathway.
It occurs in both eukaryotes and prokaryotes.	It occurs in eukaryotes.

Difference between Aerobic and Anaerobic Respiration

Summary 

All plant and animal cells produce energy through a process called cellular respiration. Due to the conversion of glucose into two pyruvates, 8 ATP molecules are produced in glycolysis. In the Krebs cycle, 12 ATP is produced as a result of the production of 2 \(C{O_2}\), 3 NADH, and 1 \(FAD{H_2}\). 32 ATP molecules are generated during oxidative phosphorylation and ETC.

Frequently Asked Questions

1.How do electron carriers function?,
Ans. The metabolite is present at one end and oxygen is at the other end, therefore the electrons are carried by a series of proteins.

2. What are the processes in the conversion of glucose to pyruvate that require energy?
Ans. By using enzymes in intermediary processes, glyceraldehyde 3-phosphate and dihydroxyacetone phosphate are produced from glucose. These processes call for energy.

3. What is oxidative phosphorylation?
Ans. Oxidative phosphorylation, which takes place in the mitochondria, is the addition of the phosphate group through reactions that use the energy produced when ATP is made from ADP.

4. What is the importance of cellular respiration in living organisms?
Ans. Energy is released during cellular respiration, which activates a number of bodily processes. Therefore, ensuring the survival of living things is important.

Introduction

The air is a fundamental element of planet Earth that sustains life. The broad term “air” is used to describe the mixture of gases that makes up the earth’s atmosphere. It is a clear gas required for breathing and performing regular cellular activities. Air is a very essential and makes up the atmosphere of the earth.

It has the following other applications-

• All life depends on air to thrive, including humans, plants, animals, and other species.
• The air is necessary for the water cycle to take place.
• It facilitates combustion and breathing.
• It keeps the temperature constant.
• Air assists in the process of pollination in wind-pollinated plants.

Components of Air

The air around is composed of various components given below-

• Oxygen makes up around 21% of the air.
• The highest amount of gas present in the air is Nitrogen, which makes up 78% of the total air.
• Argon is 0.9% of the total air.
• Carbon dioxide is the lowest around 0.04% of the air.
• There are still other gases which are present in very lower concentrations eg. water vapour.
• Microscopic airborne particles known as “aerosols”  are also present in the air and are present in minute quantities.
• These aerosols include bacteria, suspended dust, pollen, and spores.

Properties of Air

• Air is colourless and odourless and cannot be seen, heard or touched.
• It is a mixture of many gases and they occupy space and matter.
• Air exerts pressure. Near the surface, the air pressure is more and at higher altitudes the air pressure is low.
• When heated the air expands and when cooled the air compresses.

Uses of Air

Respiration

• Respiration is the process where gaseous exchange occurs and oxygen is inhaled and carbon dioxide is exhaled.
• The two main gases involved in respiration are carbon dioxide and oxygen.
• Plants and animals require oxygen to convert the chemical energy found in food into energy that can be used for various metabolic processes.
• This energy is used in all actions of growth, development, locomotion and reproduction.
• Oxygen is created through the process of photosynthesis, which occurs when plants use carbon dioxide to make chemical energy while utilizing light energy.
  

Combustion

• A fuel oxidises when it is burned and produces lots of energy.
• This is an exothermic reaction wherein light and heat are generated.
• Any carbon-containing substance that is burned in the presence of oxygen produces carbon dioxide, water vapour, heat, and light energy.
• Colourful flames are created when methane, an essential element of combustion, combines with air. These colourful flames are an indicator of the combustion reaction.
• Explosive burning might occur if there is too much oxygen present hence to prevent this nitrogen gas is present in the atmosphere.
• Nitrogen does not contribute to combustion and inhibits too much oxygen from causing higher reactivity. Therefore, these two components work together to make sure that fuel energy is used in a controlled way.
• The heat that is generated during the process of combustion is used to cook, run our vehicles, generate electricity etc.

Regulation of temperature

• The earth’s surface is kept at a constant temperature by air.
• The density of hot air is less and hence it rises above the ground. This leads to the formation of a low-pressure area which is quickly filled by cool air.
• This phenomenon leads to the formation of winds.
• As the temperature of the air rises the air moves up draws in cooler air from the surroundings, warms it up, and the cycle repeats.
• When hot air rises, it radiates heat into space before sinking back to earth.
• Convection is the process of moving heat, and this is referred to as temperature regulation.
• Heat is transferred in this way from hotter to colder places and thus the temperature of the earth is regulated.
• The atmosphere and air also help to cool the earth and protect it from the sun’s excessive UV rays.

Summary

Air surrounding the earth makes up its atmosphere. The air is a mixture of gases and is essential to many living things. Air consists of 78% of nitrogen, 21% oxygen, 0.9% argon, and 0.04% carbon dioxide, and there are traces of other gases as well. The thick layer of air supports vital life-supporting activities. Contrarily, air is a substance and it has mass, can be compressed, and takes up space. Air performs the following major processes—breathing, combustion, and regulating the earth’s temperature.

Frequently Asked Question

1. Give the function of the ozone layer
Ans: The ozone layer, which is found in the stratosphere of the earth and absorbs the majority of the sun’s ultraviolet rays, works as a screen to protect the planet from these rays.

2. What does acid rain mean?
Ans: Polluted air consists of oxides of nitrates and sulphates. These oxides react with water vapour and other air components to form sulfuric acid and nitric acid. When there is rainfall both of these acids fall on earth which is termed acid rain. This acid rain is not only harmful to people but also affects various other living organisms.

3. What are the ill effects of air pollution?
Ans: Air pollution is a very severe problem that aggravates pre-existing respiratory and cardiac problems and causes several pollution-related ailments. Common diseases caused due by air pollution are lung cancer, stroke, chronic obstructive pulmonary disease (COPD), and respiratory infections.