FACTOID # 5: Minnesota and Connecticut are both in the top 5 in saving money and total tax burden per capita.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Cellular respiration

Cellular respiration was discovered by mad scientist Mr. Lenz while jogging with his one legged grandmother. As she hobbled to the finish line (before Lenz) she inhaled a floating cell and called it cellular respiration. reactions and processes that take place in a cell or across the cell membrane to obtain biochemical energy from fuel molecules and the release of the cells' waste products. Energy is released by the oxidation of fuel molecules and is stored as "high-energy" carriers. The reactions involved in respiration are catabolic reactions in metabolism. Oh, and this first paragraph is basically a load of bologna. Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... This article is being considered for deletion in accordance with Wikipedias deletion policy. ... The most fundamental reactions in chemistry are the redox processes. ... Anabolism is the aspect of metabolism that contributes to growth. ...


Fuel molecules commonly used by cells in respiration include glucose, amino acids and fatty acids, and a common oxidizing agent (electron acceptor) is molecular oxygen (O2). There are organisms, however, that can respire using other organic molecules as electron acceptors instead of oxygen. Organisms that use oxygen as a final electron acceptor in respiration are described as aerobic, while those that do not are referred to as anaerobic. Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid (or organic acid), often with a long aliphatic tail (long chains), either saturated or unsaturated. ... European Union Chemical hazard symbol for oxidizing agents Dangerous goods label for oxidizing agents Oxidizing agent placard An oxidizing agent (also called an oxidant or oxidizer) is A chemical compound that readily transfers oxygen atoms or A substance that gains electrons in a redox chemical reaction. ... An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Organic may refer to: Look up organic in Wiktionary, the free dictionary. ... Look up Aerobic in Wiktionary, the free dictionary. ... Aerobic and anaerobic bacteria can be identified by growning them in liquid culture: 1: Obligate aerobic bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen. ...


The energy released in respiration is used to synthesize molecules that act as a chemical storage of this energy. One of the most widely used compounds in a cell is adenosine triphosphate (ATP) and its stored chemical energy can be used for many processes requiring energy, including biosynthesis, locomotion or transportation of molecules across cell membranes. Because of its ubiquitous nature, ATP is also known as the "universal energy currency", since the amount of it in a cell indicates how much energy is available for energy-consuming processes. Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Biosynthesis is a phenomenon where chemical compounds are produced from simpler reagents. ... In a general sense, locomotion simply means active movement or travel, applying not just to biological individuals. ... Look up cell membrane in Wiktionary, the free dictionary. ...

Contents

Aerobic respiration

Aerobic respiration requires oxygen in order to generate energy (ATP). It is the preferred method of pyruvate breakdown from glycolysis and requires that pyruvate enter the mitochondrion to be fully oxidized by the Krebs cycle. The product of this process is energy in the form of ATP (Adenosine Triphosphate), by substrate-level phosphorylation, NADH and FADH2. General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Pyruvate (CH3COCOO−) is the ionized form of pyruvic acid. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle that is found in most eukaryotic cells. ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Substrate-level phosphorylation is a type of chemical reaction that results in the formation of adenosine triphosphate (ATP) by the direct transfer of a phosphate group to adenosine diphosphate (ADP) from a reactive intermediate. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Flavin is also the name of a commune in the Aveyron département, in France Flavin adenine dinucleotide (FAD), upper, reduced FAD (FADH2), lower Flavin is a tricyclic heteronuclear organic ring whose biochemical source is the vitamin riboflavin. ...


Simplified Reaction: C6H12O6 (aq) + 6O2 (g) → 6CO2 (g) + 6H2O (l) ΔHc -2880 kJ


The reducing potential of NADH and FADH2 is converted to more ATP through an electron transport chain with oxygen as the "terminal electron acceptor". Most of the ATP produced by aerobic cellular respiration is made by oxidative phosphorylation. This works by the energy released in the consumption of pyruvate being used to create a chemiosmotic potential by pumping protons across a membrane. This potential is then used to drive ATP synthase and produce ATP from ADP. Biology text books often say that between 36-38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 32-34 from the electron transport system). However, this maximum yield is never quite reached due to losses (leaky membranes) as well as the cost of moving pyruvate and ADP into the mitochondrial matrix. The Electron Transport Chain. ... The Electron Transport Chain. ... Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ...


Aerobic metabolism is more efficient than anaerobic metabolism (which yields 2 mol ATP per 1 mol glucose). They share the initial pathway of glycolysis but aerobic metabolism continues with the Krebs cycle and oxidative phosphorylation. The post glycolytic reactions take place in the mitochondria in eukaryotic cells, and in the cytoplasm in prokaryotic cells. The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Organelles. ... Prokaryotes (pro-KAR-ee-oht) (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos, pl. ...


Glycolysis

Main article: Glycolysis

Glycolysis is a metabolic pathway that is found in the cytoplasm of cells in all living organisms and does not require oxygen. The process converts one molecule of glucose into two molecules of pyruvate, and makes energy in the form of two net molecules of ATP. Four molecules of ATP per glucose are actually produced; however, two are consumed for the preparatory phase. The initial phosphorylation of glucose is required to destabilize the molecule for cleavage into two triose sugars. During the pay-off phase of glycolysis four phosphate groups are transferred to ADP by substrate-level phosphorylation to make four ATP and two NADH are produced when the triose sugars are oxidized. Glycolysis takes place in the cytoplasm of the cell. The overall reaction can be expressed this way: The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Pyruvate (CH3COCOO−) is the ionized form of pyruvic acid. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... A phosphorylated serine residue Phosphorylation is the addition of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule. ... A triose is a monosaccharide containing three carbon atoms. ... This article is about sugar as food and as an important and widely-traded commodity. ... The word glycolysis is derived from Greek γλυκύς (sweet) and λύσις (rupture). ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... Substrate-level phosphorylation is a type of chemical reaction that results in the formation of adenosine triphosphate (ATP) by the direct transfer of a phosphate group to adenosine diphosphate (ADP) from a reactive intermediate. ... Organelles. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the...

Glucose + 2 ATP + 2 NAD+ + 2 Pi + 4 ADP → 2 pyruvate + 2 ADP + 2 NADH + 4 ATP + 2 H2O

Oxidative decarboxylation of pyruvate

The pyruvate produced in glycolysis is transported across the mitochondrial membranes by a membrane transport protein called the pyruvate carrier.[1] The pyruvate decarboxylase then produces acetyl-CoA from pyruvate inside the mitochondrial matrix. This oxidation reaction also releases carbon dioxide as a product. In the process one molecule of NADH is formed per pyruvate oxidized. It has been suggested that this article or section be merged with pyruvate dehydrogenase complex. ... A membrane transport protein is a protein involved in the movement of a chemical such as an ion or another protein across a biological membrane. ... Categories: Biochemistry stubs | Thiols ... In biology, the word matrix is used for the material between animal or plant cells, or generally the material (or tissue) in which more specialized structures are embedded, and also specifically for one part of the mitochondrion. ...


Citric Acid cycle/Krebs cycle

Main article: Citric acid cycle

When oxygen is present, acetyl-CoA is produced from pyruvate. If oxygen is not present the cell undergoes fermentation of the pyruvate molecule. If acetyl-CoA is produced the molecule then enters the citric acid cycle (Krebs cycle) inside the mitochondrial matrix, and gets oxidized to CO2 while at the same time reducing NAD to NADH. NADH can be used by the electron transport chain to create further ATP as part of oxidative phosphorylation. To fully oxidize the equivalent of one glucose molecule two acetyl-CoA must be metabolized by the Krebs cycle. Two waste products, H2O and CO2 are created during this cycle. Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Categories: Biochemistry stubs | Thiols ... Categories: Biochemistry stubs | Thiols ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ... Nicotinamide adenine dinucleotide (NAD+ or in older notation DPN+) is an important coenzyme found in cells. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... The Electron Transport Chain. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Cellular waste products are formed as a byproduct of cellular respiration, a series of processes and reactions that generate energy for the cell, in the form of ATP. Two examples of cellular respiration creating cellular waste products are aerobic respiration and anaerobic respiration. ...


Oxidative phosphorylation

In eukaryotes, oxidative phosphorylation occurs in the mitochondrial cristae. It comprises the electron transport chain that establishes a proton gradient (chemiosmotic potential) across the inner membrane by oxidizing the NADH produced from the Krebs cycle. ATP is synthesised by the ATP synthase enzyme when the chemiosmotic gradient is used to drive the phosphorylation of ADP. The Electron Transport Chain. ... The Electron Transport Chain. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ... An ATP synthase (EC 3. ... Mitochondria structure : 1) Inner membrane 2) Outer membrane 3) Crista 4) Matrix Cristae (singular crista) are the internal compartments formed by the inner membrane of a mitochondrion. ... An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. ...


Theoretical yields

The yields in the table below are for one glucose molecule being fully oxidized into carbon dioxide. It is assumed that all the reduced coenzymes are oxidized by the electron transport chain and used for oxidative phosphorylation. The most fundamental reactions in chemistry are the redox processes. ... Coenzyme A Coenzymes are small organic non-protein molecules that carry chemical groups between enzymes. ...

Step coenzyme yield ATP yield Source of ATP
Glycolysis preparatory phase -2 Phosphorylation of glucose and fructose 6-phosphate uses two ATP from the cytoplasm.
Glycolysis pay-off phase 4 Substrate-level phosphorylation
2 NADH 4 (6) Oxidative phosphorylation. Only 2 ATP per NADH since the coenzyme must feed into the electron transport chain from the cytoplasm rather than the mitochondrial matrix. If the malate shuttle is used to move NADH into the mitochondria this might count as 3 ATP per NADH.
Oxidative decarboxylation 2 NADH 6 Oxidative phosphorylation
Krebs cycle 2 Substrate-level phosphorylation
6 NADH 18 Oxidative phosphorylation
2 FADH2 4 Oxidative phosphorylation
Total yield 36 (38) ATP From the complete oxidation of one glucose molecule to carbon dioxide and oxidation of all the reduced coenzymes.

Although there is a theoretical yield of 36-38 ATP molecules per glucose during cellular respiration, such conditions are generally not realized due to losses such as the cost of moving pyruvate (from glycolysis), phosphate and ADP (substrates for ATP synthesis) into the mitochondria. All are actively transported using carriers that utilise the stored energy in the proton electrochemical gradient. Diagram Illustrating the Malate-Asparate Shuttle Pathway The malate-aspartate shuttle (sometimes also the malate shuttle) is a biochemical system for translocating electrons produced during glycolysis across the impermeable inner membrane of the mitochondrion for oxidative phosphorylation in eukaryotes. ... In cellular biology, an electrochemical gradient refers to the electrical and chemical properties across a membrane. ...

  • The pyruvate carrier is a symporter and the driving force for moving pyruvate into the mitochondria is the movement of protons from the intermembrane space to the matrix.
  • The phosphate carrier is an antiporter and the driving force for moving phosphate ions into the mitochondria is the movement of hydroxyls ions from the matrix to the intermembrane space.
  • The adenine nucleotide carrier is an antiporter and exchanges ADP and ATP across the inner membrane. The driving force is due to the ATP (-4) having a more negative charge than the ADP (-3) and thus it dissipates some of the electrical component of the proton electrochemical gradient.

The outcome of these transport processes using the proton electrochemical gradient is that more than 3 H+ are needed to make 1 ATP. Obviously this reduces the theoretical efficiency of the whole process and the likely maximum is closer to 28-30 ATP molecules.[2] In practice the efficiency may be even lower due to the inner membrane of the mitochondria being slightly leaky to protons.[3] Other factors may also dissipate the proton gradient creating an apparently leaky mitochondria. An uncoupling protein known as thermogenin is expressed in some cell types and is a channel that can transport protons. When this protein is active in the inner membrane it short circuits the coupling between the electron transport chain and ATP synthesis. The potential energy from the proton gradient is not used to make ATP but generates heat. This is particularly important in a baby's brown fat, for thermogenesis, and hibernating animals. A symporter, also known as a coporter, is an integral membrane protein that is involved in facilitated diffusion. ... The intermembrane space is the region between the inner membrane and the outer membrane of a mitochondrion or a chloroplast. ... An antiporter is an integral membrane protein that is involved in secondary active transport. ... Adenine nucleotide translocator is a mitochondrial protein. ... The inner membrane is a membrane (phospholipid bilayer) of an organelle that is within the outer membrane. ... Thermogenin is a protein that helps generating heat in a cell by allowing protons to go back into the mitochondrion without having to go through ATP synthase. ... The Electron Transport Chain. ... An ATP synthase (EC 3. ...


Anaerobic respiration

Main article: Anaerobic respiration

Without oxygen, pyruvate is not metabolized by cellular respiration but undergoes a process of fermentation. The pyruvate is not transported into the mitochondrion, but remains in the cytoplasm, where it is converted to waste products that may be removed from the cell. This serves the purpose of oxidizing the hydrogen carriers so that they can perform glycolysis again and removing the excess pyruvate. This waste product varies depending on the organism. In skeletal muscles, the waste product is lactic acid. This type of fermentation is called lactic acid fermentation. In yeast, the waste products are ethanol and carbon dioxide. This type of fermentation is known as alcoholic or ethanol fermentation. Anaerobic respiration refers to the oxidation of molecules in the absence of oxygen to produce energy, in opposition to Aerobic respiration which does use oxygen. ... It has been suggested that this article or section be merged with Fermentation (food). ... Cellular waste products are formed as a byproduct of cellular respiration, a series of processes and reactions that generate energy for the cell, in the form of ATP. Two examples of cellular respiration creating cellular waste products are aerobic respiration and anaerobic respiration. ... For the production of milk by mammals, see Lactation. ... Lactic acid Lactic acid fermentation is a form of anaerobic respiration that occurs in some bacteria and animal cells in the absence of oxygen. ... “Grain alcohol” redirects here. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Ethanol fermentation is a form of anaerobic respiration used primarily by yeasts when oxygen is not present in sufficient quantity for normal cellular respiration, the cellular energy-producing system, to continue. ...


Anaerobic respiration is less efficient at using the energy from glucose since 2 ATP are produced during anaerobic respiration per glucose, compared to the 30 ATP per glucose produced by aerobic respiration. This is because the waste products of anaerobic respiration still contain plenty of energy. Ethanol, for example, can be used in gasoline (petrol) solutions. Glycolytic ATP, however, is created more quickly. For prokaryotes to continue a rapid growth rate when they are shifted from an aerobic environment to an anaerobic environment, they must increase the rate of the glycolytic reactions. Thus, during short bursts of strenuous activity, muscle cells use anaerobic respiration to supplement the ATP production from the slower aerobic respiration, so anaerobic respiration may be used by a cell even before the oxygen levels are depleted, as is the case in sports that do not require athletes to pace themselves, such as sprinting. Cellular waste products are formed as a byproduct of cellular respiration, a series of processes and reactions that generate energy for the cell, in the form of ATP. Two examples of cellular respiration creating cellular waste products are aerobic respiration and anaerobic respiration. ... “Grain alcohol” redirects here. ... Sprints are short running races in athletics. ...


See also

Tetrazolium chloride is a redox indicator commonly used in biochemical experiments especially to indicate cellular respiration. ...

References

  1. ^ Sugden MC, Holness MJ (2003). "Trials, tribulations and finally, a transporter: the identification of the mitochondrial pyruvate transporter". Biochem. J. 374 (Pt 3): e1–2. PMID 12954079. 
  2. ^ Rich PR (2003). "The molecular machinery of Keilin's respiratory chain". Biochem. Soc. Trans. 31 (Pt 6): 1095-105. PMID 14641005. 
  3. ^ Porter RK, Brand MD (1995). "Mitochondrial proton conductance and H+/O ratio are independent of electron transport rate in isolated hepatocytes". Biochem. J. 310 ( Pt 2): 379-82. PMID 7654171. 

Protein metabolism denotes the various biochemical processes responsible for the synthesis of proteins and amino acids, and the breakdown of proteins (catabolism). ... The smooth endoplasmic reticulum is responsible for some carbohydrate metabolism. ... This article or section is in need of attention from an expert on the subject. ... Human beings use 20 mg of iron each day for the production of new red blood cells, much of which is recycled from old red blood cells. ...

External links


  Results from FactBites:
 
Cellular Respiration (1353 words)
Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water.
The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell.
The energy stored in the proton gradient is also used for the active transport of several molecules and ions through the inner mitochondrial membrane into the matrix.
Understanding cellular respiration (871 words)
Cellular respiration is the process by which food is broken down by the body's cells to produce energy, in the form of ATP molecules.
Cellular respiration is carried out by every cell in both plants and animals and is essential for daily living.
Cellular respiration is an almost universal process by which organisms utilize the sugars in their food to produce enough energy to perform all the necessary actions of living creatures.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m