Cellular respiration

respirationaerobic respirationaerobicaerobic metabolismoxidative metabolismaerobicallyrespireaerobic glycolysisaerobecell respiration
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.wikipedia
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Metabolism

metabolicmetabolizedmetabolic pathways
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
Metabolic reactions may be categorized as catabolic - the breaking down of compounds (for example, the breaking down of glucose to pyruvate by cellular respiration); or anabolic - the building up (synthesis) of compounds (such as proteins, carbohydrates, lipids, and nucleic acids).

Oxygen

OO 2 molecular oxygen
Nutrients that are commonly used by animal and plant cells in respiration include sugar, amino acids and fatty acids, and the most common oxidizing agent (electron acceptor) is molecular oxygen (O 2 ).
Dioxygen is used in cellular respiration and many major classes of organic molecules in living organisms contain oxygen, such as proteins, nucleic acids, carbohydrates, and fats, as do the major constituent inorganic compounds of animal shells, teeth, and bone.

Adenosine triphosphate

ATPadenosine triphosphate (ATP)adenosine 5'-triphosphate
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The products of this process are carbon dioxide and water, but the energy transferred is used to break bonds in ADP as the third phosphate group is added to form ATP (adenosine triphosphate), by substrate-level phosphorylation, NADH and FADH 2 In aerobic conditions, the process converts one molecule of glucose into two molecules of pyruvate (pyruvic acid), generating energy in the form of two net molecules of ATP.
The overall process of oxidizing glucose to carbon dioxide, the combination of pathways 1 and 2, is known as cellular respiration, produces about 30 equivalents of ATP from each molecule of glucose.

Glycolysis

glycolyticglycolytic pathwayEmbden–Meyerhof pathway
Although carbohydrates, fats, and proteins are consumed as reactants, it is the preferred method of pyruvate breakdown in glycolysis and requires that pyruvate enter the mitochondria in order to be fully oxidized by the Krebs cycle. The total ATP yield in ethanol or lactic acid fermentation is only 2 molecules coming from glycolysis, because pyruvate is not transferred to the mitochondrion and finally oxidized to the carbon dioxide (CO 2 ), but reduced to ethanol or lactic acid in the cytoplasm.
Cells performing aerobic respiration synthesize much more ATP, but not as part of glycolysis.

Cell (biology)

cellcellscellular
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.

Anaerobic respiration

anaerobicanaerobic metabolismanaerobically
However, some anaerobic organisms, such as methanogens are able to continue with anaerobic respiration, yielding more ATP by using other inorganic molecules (not oxygen) as final electron acceptors in the electron transport chain.
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O 2 ).

Flavin adenine dinucleotide

FADFADH 2 FADH2
The products of this process are carbon dioxide and water, but the energy transferred is used to break bonds in ADP as the third phosphate group is added to form ATP (adenosine triphosphate), by substrate-level phosphorylation, NADH and FADH 2
German scientists Otto Warburg and Walter Christian discovered a yeast derived yellow protein required for cellular respiration in 1932.

Electron transport chain

respiratory chainelectron transportmitochondrial respiratory chain
The potential of NADH and FADH 2 is converted to more ATP through an electron transport chain with oxygen as the "terminal electron acceptor". When this protein is active in the inner membrane it short circuits the coupling between the electron transport chain and ATP synthesis.
The final acceptor of electrons in the electron transport chain during aerobic respiration is molecular oxygen although a variety of acceptors other than oxygen such as sulfate exist in anaerobic respiration.

Oxidative phosphorylation

ATP generationmitochondrial oxidative phosphorylationoxidative
Most of the ATP produced by aerobic cellular respiration is made by oxidative phosphorylation.
It is the terminal process of cellular respiration in eukaryotes and accounts for high ATP yield.

Substrate-level phosphorylation

substrate level phosphorylationsubstrate phosphorylation
The products of this process are carbon dioxide and water, but the energy transferred is used to break bonds in ADP as the third phosphate group is added to form ATP (adenosine triphosphate), by substrate-level phosphorylation, NADH and FADH 2
Substrate-level phosphorylation occurs in the cytoplasm of cells during glycolysis and in mitochondria either during the Krebs cycle or by MTHFD1L ( EC 6.3.4.3), an enzyme interconverting ADP + phosphate + 10-formyltetrahydrofolate to ATP + formate + tetrahydrofolate (reversibly), under both aerobic and anaerobic conditions.

Pyruvate dehydrogenase complex

pyruvate dehydrogenasemitochondrial pyruvate dehydrogenase complexPDC
Pyruvate is oxidized to acetyl-CoA and CO 2 by the pyruvate dehydrogenase complex (PDC).
Acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration, and this complex links the glycolysis metabolic pathway to the citric acid cycle.

Eukaryote

Eukaryotaeukaryoticeukaryotes
The post-glycolytic reactions take place in the mitochondria in eukaryotic cells, and in the cytoplasm in prokaryotic cells.
They have two surrounding membranes, each a phospholipid bi-layer; the inner of which is folded into invaginations called cristae where aerobic respiration takes place.

Cellular waste product

waste productscellular productwastes
Two waste products, H 2 O and CO 2, are created during this cycle.
Cellular waste products are formed as a by-product of cellular respiration, a series of processes and reactions that generate energy for the cell, in the form of ATP.

Carbon dioxide

CO 2 CO2carbon dioxide (CO 2 )
In the presence of oxygen, when acetyl-CoA is produced, the molecule then enters the citric acid cycle (Krebs cycle) inside the mitochondrial matrix, and is oxidized to CO 2 while at the same time reducing NAD to NADH.
is produced by all aerobic organisms when they metabolize carbohydrates and lipids to produce energy by respiration.

ATP synthase

ATP synthesisATPATPase
When this protein is active in the inner membrane it short circuits the coupling between the electron transport chain and ATP synthesis.
In order to drive this reaction forward, ATP synthase couples ATP synthesis during cellular respiration to an electrochemical gradient created by the difference in proton (H + ) concentration across the mitochondrial plasma membrane in eukaryotes or the plasma membrane in bacteria.

Crista

cristaecristae.mitochondrial cristae
In eukaryotes, oxidative phosphorylation occurs in the mitochondrial cristae.
This aids aerobic cellular respiration, because the mitochondrion requires oxygen.

Fermentation

fermentedfermentfermenting
The total ATP yield in ethanol or lactic acid fermentation is only 2 molecules coming from glycolysis, because pyruvate is not transferred to the mitochondrion and finally oxidized to the carbon dioxide (CO 2 ), but reduced to ethanol or lactic acid in the cytoplasm.
In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of respiration.

Electron acceptor

acceptorterminal electron acceptoracceptors
Nutrients that are commonly used by animal and plant cells in respiration include sugar, amino acids and fatty acids, and the most common oxidizing agent (electron acceptor) is molecular oxygen (O 2 ).
In biology, a terminal electron acceptor is a compound that receives or accepts an electron during cellular respiration or photosynthesis.

Carbohydrate

carbohydratessaccharidecomplex carbohydrates
Although carbohydrates, fats, and proteins are consumed as reactants, it is the preferred method of pyruvate breakdown in glycolysis and requires that pyruvate enter the mitochondria in order to be fully oxidized by the Krebs cycle.
Plant components are consumed by animals and fungi, and used as fuel for cellular respiration.

Lactic acid fermentation

lactic fermentationlactic acidlacto-fermented
The total ATP yield in ethanol or lactic acid fermentation is only 2 molecules coming from glycolysis, because pyruvate is not transferred to the mitochondrion and finally oxidized to the carbon dioxide (CO 2 ), but reduced to ethanol or lactic acid in the cytoplasm.
If oxygen is present in the cell, many organisms will bypass fermentation and undergo cellular respiration; however, facultative anaerobic organisms will both ferment and undergo respiration in the presence of oxygen.

Glucose

dextroseD-glucose D -glucose
In aerobic conditions, the process converts one molecule of glucose into two molecules of pyruvate (pyruvic acid), generating energy in the form of two net molecules of ATP.
It is used as an energy source in organisms, from bacteria to humans, through either aerobic respiration, anaerobic respiration (in bacteria), or fermentation.

Chemiosmosis

proton motive forcechemiosmoticproton-motive force
An example of this would be the generation of adenosine triphosphate (ATP) by the movement of hydrogen ions (H + ) across a membrane during cellular respiration or photosynthesis.

Mitochondrion

mitochondriamitochondrialmitochondrial membrane
Although carbohydrates, fats, and proteins are consumed as reactants, it is the preferred method of pyruvate breakdown in glycolysis and requires that pyruvate enter the mitochondria in order to be fully oxidized by the Krebs cycle. The total ATP yield in ethanol or lactic acid fermentation is only 2 molecules coming from glycolysis, because pyruvate is not transferred to the mitochondrion and finally oxidized to the carbon dioxide (CO 2 ), but reduced to ethanol or lactic acid in the cytoplasm.
The ability of these bacteria to conduct respiration in host cells that had relied on glycolysis and fermentation would have provided a considerable evolutionary advantage.

Metabolic pathway

metabolic pathwayspathwaypathways
Glycolysis is a metabolic pathway that takes place in the cytosol of cells in all living organisms.
Additionally, most organisms can perform more efficient aerobic respiration through the citric acid cycle and oxidative phosphorylation.

Proton pump

proton channelproton pumpsH + -ATPase
In cell respiration, the proton pump uses energy to transport protons from the matrix of the mitochondrion to the inter-membrane space.