(7)	Cellular+respiration+–+The+process

We digest food to produce glucose, for energy. If we don't have glucose, the source of energy in our bodies, we won't be able to do everyday activities.
 * Introduction**

**W****hat is Cellular Respiration?** As we all know, cells need energy for cell activity. Cellular respiration is basically a term for biochemical pathways, which cells release energy from chemical bonds of food molecules; to provide energy for the maintenance of essential life processes. All living cells go through the process of cellular respiration, both prokaryotic and eukaryotic cells. Cellular respiration can be both aerobic and anaerobic, with oxygen and without oxygen. Glucose is used in cellular respiration for the production of ATP.

Prokaryotic cells complete the cellular respiration process within the cytoplasm. The cellular respiration process happens in the mitochondria for eukaryotic cells.

**How About ATP?** The energy currency of cells is ATP or adenosine triphosphate. One way to think of cellular respiration is that the outcome of the process is energy, which is later used to produce ATP. The energy process may be used for heating the cells as well.

**Cellular Respiration Stages** There are four main stages of cellular respiration. They are: Glycolysis, transition reaction, the citric acid cycle and electron transport.



Glycolysis is when one glucose, which is 6 carbons, 12 hydrogen and 6 oxygen, is broken down in the cytoplasm into 2 pyruvic acid. There are 2 ATPs produced per glucose.

In a cellular respiration system, there are two types of respiration, which are aerobic respiration and anaerobic respiration.
 * Aerobic and Anaerobic Respiration: **

__ Aerobic Respiration - __ Aerobic Respiration contains four steps, and these are: 1. Glycolysis This is a process that occurs in the cytoplasm, where six carbon glucose molecules are converted into two or three carbon molecules of pyruvate. In order to initiate the process, two energy (ATP) molecules are consumed, but two other NADH molecules are produced after the process. 2. Formation of Acetyl Coenzyme A This is a process that invovles the mix of pyruvate molecules in the mitochondria. Each of the pryvute molecules oxidizes into the carbon dioxide molecules, where forming a two separate carbon acetyle molecule. After, when carbon dioxide is released as a waste in the cell, these two molecules will be converted into the coenzyme A, brining the waste back into the mitochondria. 3. Citric Acid Cycle The two carbon acetyl group produced from the glucose molecule bounds to a pre-existing molecule (oxaloacetate) to form a citrate. When this citric molecules get oxidized, the hydrogen ion converts itself to NAD to NADH to FAD to FADH2, meaning that it will keep change form, as metabolism happens where ever the hydrogen goes to. The oxaloacetate produces the last carbon atom in the form of carbon dioxide, and the ATP molecules synthesizes this for glucose molecules to enter the cell. 4. Electron transport chain and chemiosmosis The electrons get removed from an atom as the glycolysis citric acid follows cytochromes over the mitochondrial memebrane, and then the hydrogen ions gets pumped across the inner membrane of a mitochondria. this flow of protons goes through the ATP, releasing the energy and creates 34 new ATP molecules

This is a diagram that explains the citric acid cycle in the "atom world". __Anaerobic Respiration:__ Anaerobic Respiration is usually a common method of breathing for organisms that live in places where there are lack of oxygen. Glycolsis is present. but does not require oxygen, as the glycolsis contains NAD+, being provided by the oxygen from ETCs. As there are lack of oxygen, the process of take in (inhale) will be lost but fermentation will take its place. Fermentation is the supply of NAD+, to help the glycolysis's function of continuous produce of ATP.

"Aerobic Respiration." //CBU//. N.p., n.d. Web. 4 Mar. 2012. .

Transition reaction is when the pyruvate acid is transported into the mitochondria, which is then converted into an Acetyl CoA. During the Krebs or the citric acid cycle, Acetyl CoA is oxidized to carbon dioxide, which chemical energy is released or captured in the form of NADH, FADH 2 and ATP. The cycle happens in the matrix, the fluid area inside the inner membrane of the mitochondria. Nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD) are compounds produced by two ATP molecules. These compounds are capable of storing high energy electrons. The cycle only happens when oxygen is presented although there is no direct use.

media type="youtube" key="Kb-4uuCYLvE" height="390" width="640" Canadianfnessari, host. //NAD+ How the NAD+ Works in Cell//. //Youtube//. Youtube LLC,, n.d. Web. 20 Feb. 2012. .
 * Condused about just what NADH is? Watch this Video:**

Electron transport is many electron carriers in the membrane of the mitochondria. Through the reactions, the high energy electrons are changed to oxygen. Ultimately, ATP is produced. There are approximately 38 ATPs per glucose.

media type="youtube" key="xbJ0nbzt5Kw" height="390" width="640" Ndsuvirtualcell, host. //Cellular Respiration (Electron Transport Chain)//.
 * Simplified Animation of the Electron Transport Chain:**

//Youtube//. Youtube LLC,, n.d. Web. 19 Feb. 2012. [].

media type="youtube" key="3y1dO4nNaKY" height="390" width="640" Ndsuvirtualcell, host. //Gradients (ATP Synthase)//. //Youtube//. Youtube LLC,, n.d. Web. 19 Feb. 2012. .
 * Simplified Animation of The ATP Synthase Complex:**

Prokaryotic cells produce a maximum of 38 ATP molecules while eukaryotic produce a maximum of 36 ATP molecules. Eukaryotic loses 2 ATPs because the NADH molecules produced through glycolysis go through the mitochondrial membrane.

In the case where there is no oxygen, anaerobic respiration occurs. The result is only 2 ATPs because the cells use anaerobic metabolism, the ATPs are produced in glycolysis stage.

To learn more about anaerobic respiration, go to this link

Some videos that introduce the cellular respiration, creatively

media type="youtube" key="3aZrkdzrd04" height="315" width="420" media type="youtube" key="2f7YwCtHcgk" height="315" width="560" **Works Cited** Bailey, Regina. “Cellular Respiration.” //About//. The New York Times, 2012. Web. 13 Feb. 2012. . “Cell Respiration: Overview of Respiration.” //BioCoach//. Pearson, n.d. Web. 13 Feb. 2012. . “Cellular Respiration.” //IUPUI Department of Biology//. N.p., 2004. Web. 13 Feb. 2012. . Hsu, Mr. //Cellular Respiration Song//. //Youtube//. N.p., 1 Jan. 2010. Web. 13 Feb. 2012. . //Introduction to Cellular Respiration//. //Youtube//. N.p., 8 Dec. 2009. Web. 13 Feb. 2012. . Nave, Carl Rod. “Cellular Respiration.” //Hyper Physics//. N.p., 2011. Web. 13 Feb. 2012. . Sharma, Abhisshake. //Cellular Respiration Diagram//. N.d. //Buzzle//. N.p., n.d. Web. 13 Feb. 2012. .
 * This is a song about cellular respiration and the stages **
 * This is a video that introduces cellular respiration, made by Khan Academy **