Respiration

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Respiratory SystemRespiratory System The Point of Cellular RespirationThe Point of Cellular Respiration Types of Cellular RespirationTypes of Cellular Respiration Composition of AirComposition of Air Gas PressureGas Pressure

Respiratory SystemRespiratory System

Primary function is Primary function is to supply the blood to supply the blood with oxygen in order with oxygen in order for the blood to for the blood to deliver oxygen to all deliver oxygen to all parts of the body.parts of the body.

The respiratory The respiratory system does this system does this through breathingthrough breathing

The Point of Cellular RespirationThe Point of Cellular Respiration

To harvest electrons from organic compounds To harvest electrons from organic compounds such as glucose and use that energy to make a such as glucose and use that energy to make a molecule called ATP.molecule called ATP.

ATP in turn is used to provide energy for ATP in turn is used to provide energy for most of the immediate work that the cell most of the immediate work that the cell doesdoes

ATP can be thought of as being like a small ATP can be thought of as being like a small package of energy that has just the right package of energy that has just the right amount of energy that can be used in a amount of energy that can be used in a controlled manner.controlled manner.

ATPATP (Adenosine tri-(Adenosine tri-phosphate): ATP is a phosphate): ATP is a nucleotidenucleotide with 3 with 3 phosphate groups phosphate groups instead of 1 phosphate instead of 1 phosphate group. The point of group. The point of cellular respiration is to cellular respiration is to harvest chemical energy harvest chemical energy from food and store it from food and store it in the chemical bonds of in the chemical bonds of ATP. In this diagram ATP. In this diagram Nitrogen=Nitrogen=blueblue, , Phosphate=Phosphate=yellowyellow, , Carbon=Carbon=greygrey, , Oxygen=Oxygen=redred. Hydrogen . Hydrogen atoms are not shownatoms are not shown

Types of Cellular RespirationTypes of Cellular Respiration There are two basic types There are two basic types

of cellular respiration of cellular respiration aerobic cellular respiration aerobic cellular respiration and anaerobic cellular and anaerobic cellular respiration. Aerobic respiration. Aerobic respiration requires the respiration requires the use of oxygen and use of oxygen and anaerobic respiration anaerobic respiration which does not use oxygen. which does not use oxygen. There are several types of There are several types of anaerobic respiration, anaerobic respiration, most familiar is a process most familiar is a process calledcalled fermentation fermentation..

Equation of Aerobic Respiration

1.Aerobic Respiration1.Aerobic Respiration – is the process by – is the process by which ATP is produced by cells by the which ATP is produced by cells by the complete oxidation of organic complete oxidation of organic compounds using oxygen.compounds using oxygen.

Oxygen serves as the final electron Oxygen serves as the final electron acceptor, accepting electrons that acceptor, accepting electrons that ultimately come from the energy rich ultimately come from the energy rich organic compounds we consume.organic compounds we consume.

In the fig. the energy rich molecules (& In the fig. the energy rich molecules (& heat) are in heat) are in redred, energy poor are in , energy poor are in blackblack..

Stages in Aerobic RespirationStages in Aerobic Respiration

GlycolysisGlycolysis – glucose is partially oxideized and broken down into 3 Carbon – glucose is partially oxideized and broken down into 3 Carbon molecules calledmolecules called pyruvatepyruvate. In the process, glycolysis produced 4 ATP for a . In the process, glycolysis produced 4 ATP for a net gain of 2 ATP & 2 molecules of net gain of 2 ATP & 2 molecules of NADHNADH. Each NADH is carrying 2 energy . Each NADH is carrying 2 energy rich electrons away from the glucose and these electrons can be used by rich electrons away from the glucose and these electrons can be used by the cell to do work. After glycolysis the pyruvate is processed to harvest 2 the cell to do work. After glycolysis the pyruvate is processed to harvest 2 more NADH mol. & remove one carbon per pyruvate. The carbon and 2 more NADH mol. & remove one carbon per pyruvate. The carbon and 2 oxygen are removed since it no longer has any useful energy. So it is waste. oxygen are removed since it no longer has any useful energy. So it is waste. This little step is the source of some of the carbon dioxide we produce.This little step is the source of some of the carbon dioxide we produce.

Kreb’s cycleKreb’s cycle – the remaining 2 carbon per pyruvate feed into a complicated – the remaining 2 carbon per pyruvate feed into a complicated set of reactions called set of reactions called Kreb’s cycleKreb’s cycle. It produces 8 more NADH molecules . It produces 8 more NADH molecules and 2 molecules of FADH2. Again both of these are carrying energy rich and 2 molecules of FADH2. Again both of these are carrying energy rich electrons.electrons.

Electron Transport PhosphorylationElectron Transport Phosphorylation – most of the NADH and FADH2 – most of the NADH and FADH2 travel to special membranes in the cell which have a series of molecules travel to special membranes in the cell which have a series of molecules called called electron transport systemelectron transport system that harvest the energy rich electrons from that harvest the energy rich electrons from the NADH & FADH2 and use that energy to make lots of ATP by a process the NADH & FADH2 and use that energy to make lots of ATP by a process called electron transport phosphorylation.called electron transport phosphorylation.

2.2. Fermentation & Anaerobic Fermentation & Anaerobic respirationrespiration – if oxygen is absent, many – if oxygen is absent, many cells are still able to use glycolysis to cells are still able to use glycolysis to produce ATP. 2 ways this can be done produce ATP. 2 ways this can be done are through fermentation and anaerobic are through fermentation and anaerobic respiration. respiration. FermentationFermentation is the process is the process by which electrons and hydrogen ions by which electrons and hydrogen ions from the NADH produced by glycolysis from the NADH produced by glycolysis are donated to another organic are donated to another organic molecule.molecule.

Stages in Anaerobic RespirationStages in Anaerobic Respiration

The Point of FermentationThe Point of Fermentation The reason this is done is to produce NAD+ The reason this is done is to produce NAD+

which in tern is needed to keep glycolysis which in tern is needed to keep glycolysis going. Remember that unless the cell has some going. Remember that unless the cell has some sort of electron transport system, the NADH sort of electron transport system, the NADH is not usable. At the same time NAD+ is is not usable. At the same time NAD+ is needed for glycolysis and its much less needed for glycolysis and its much less expensive in terms of energy for the cell to expensive in terms of energy for the cell to simply to take the NADH that would normally simply to take the NADH that would normally go to the mitochondria and use it to generate go to the mitochondria and use it to generate the NAD+.the NAD+.

Notice that the NADH produced by glycolysis Notice that the NADH produced by glycolysis donates its hydrogen ions and electrons that donates its hydrogen ions and electrons that in aerobic respiration would have ended up in aerobic respiration would have ended up powering electron transport phosphorylation. powering electron transport phosphorylation.

Composition of AirComposition of Air

Nitrogen: 78.084%Nitrogen: 78.084% Oxygen: 20.947%Oxygen: 20.947% Argon: 0.934%Argon: 0.934% Carbon Dioxide: Carbon Dioxide:

0.033%0.033%

Total: 99.998%Total: 99.998%

Human RespirationHuman Respiration

The air that leaves a person's lungs The air that leaves a person's lungs during exhalation contains 14% oxygen during exhalation contains 14% oxygen and 4.4%and 4.4%carbon dioxide.carbon dioxide.

Atmospheres with oxygen Atmospheres with oxygen concentrations below 19.5 percent can concentrations below 19.5 percent can have adverse physiological effects, and have adverse physiological effects, and atmospheres with less than 16 percent atmospheres with less than 16 percent oxygen can become life threatening. oxygen can become life threatening.

Gas PressureGas Pressure

Gas molecules inside a Gas molecules inside a volume (e.g. a balloon) volume (e.g. a balloon) are constantly moving are constantly moving around freely. During around freely. During this molecular motion this molecular motion they frequently collide they frequently collide with each other and with each other and with the surface of any with the surface of any enclosure there may be enclosure there may be (in a small balloon that (in a small balloon that would be many would be many thousands of billions of thousands of billions of collisions each second)collisions each second)

The internal gas pressure in a balloon, PB, is given by the impacts of moving gas molecules, as they collide with the skin of the balloon from the inside

The force of impact of The force of impact of a single one such a single one such collision is too small to collision is too small to be sensed. However, be sensed. However, taken all together, this taken all together, this large number of impacts large number of impacts of gas molecules exerts of gas molecules exerts a considerable force a considerable force onto the surface of the onto the surface of the enclosure: the enclosure: the gas gas pressurepressure

The larger the number The larger the number of collisions per area of of collisions per area of enclosure, the larger enclosure, the larger the pressure:the pressure:

• The SI-unit of pressure is Pascal [Pa], but in Meteorology it is accepted to use millibars [mb], where 100 kPa = 1000 mb.• The direction of this gas pressure force is always perpendicular to the surface of the enclosure at every point.