Cell respiration is catabolic. This way organic compounds are broken downward into smaller molecules (like CO2 in addition to H2O) in addition to liberate energy is released
- carbohydrates (mainly glucose) in addition to fats are the master copy sources of energy
- proteins are rarely used for liberate energy - they are of import every bit edifice blocks for increment in addition to repair - they volition exclusively live converted to carbohydrates in addition to used for liberate energy if at that spot are no carbohydrates available.
2 types of respiration:
1. Aerobic: called biological oxidation, it needs O2
-in simplified version: C6H12O6 in addition to 6 O2 react inward the presence of enzymes to produced 6 H2O, 6 CO2 and energy.
2. Anaerobic: called fermentation, it doesn't quest O2, the overall procedure is simpler in addition to faster than biological oxidation, only produces much less energy.
GLYCOLYSIS
- this is the 1st pace of both aerobic in addition to anaerobic respiration
-it occurs inward the jail cellphone cytosol
-it doesn't quest O2, only it does require liberate energy (2 ATP)
Image from http://www.factmonster.com/images/cig/biology/03fig02.png
Step 1. Energy is required to start the process, hence a molecule of glucose accepts ii high-energy phosphate groups from ii ATP molecules.
Step 2. The resulting intermediary molecule right away divides into two, three-carbon molecules called PGAL, each containing a high-energy phosphate group.
Step 3. Influenza A virus subtype H5N1 minute high-energy phosphate grouping is added to the three-carbon PGAL molecule in addition to ii NADH + H+ molecules are produced.
Step 4. Finally, the three-carbon PGAL molecules donate their high-energy phosphate to practise ATP in addition to the three-carbon pyruvate forms every bit the lastly products.
- 4 ATP molecules are produced inward glycolysis, only since 2 are required to start the process, the cyberspace gain is 2 ATP. This is non sufficient liberate energy to hold complex life systems, hence pyruvate (also called pyruvic acid) (which even hence contains energy) volition operate on into biological oxidation or fermentation, depending on the availability of O2
-if O2 is present, in addition to hence pyruvate enters the mitochondria:
AEROBIC RESPIRATION
- has 2 parts: biological oxidation and terminal oxidation
- requires O2
- occurs inward the mitochondria
Image from http://imagineannie.files.wordpress.com/2009/11/mitochondria1.jpg
Biological oxidation
-the commencement reaction occurs inward the outer membrane of the mitochondria:
pyruvate (CH3COCOOH) reacts amongst CoA (coenzyme A)to shape acetyl-CoA (CH2CO-CoA) yesteryear losing a carbon every bit CO2.
-acetyl-CoA volition operate inward the Kreb's Citric Acid Cycle in the mitochondrial matrix
Note: Acetyl-CoA is a 2-carbon compound, citric acid is a 6-carbon chemical compound in addition to oxaloacetic acid is a 4-carbon compound. When CoA is released it volition furnish to the membrane to gain to a greater extent than acetyl-CoA.
Image from http://www.factmonster.com/images/cig/biology/03fig03.png
- the ikon to a higher house is a summary of ix enzyme-controlled reactions.
Step 1. Acetyl-CoA donates the two-carbon acetyl grouping to a four-carbon intermediary compound, oxaloacetic acid, to practise the six-carbon citric acid molecule.
Step 2. The high-energy electrons are oxidized to practise the energy-rich NADH + H+ molecule when the six-carbon chemical compound loses a carbon dioxide molecule to larn a five-carbon molecule.
Step 3. Influenza A virus subtype H5N1 minute molecule of NADH + H+ in addition to a molecule of ATP are produced when some other carbon dioxide molecule is released from the five-carbon molecule, which in addition to hence degrades to a novel four-carbon molecule.
Step 4. The four-carbon molecule is farther oxidized to transfer high-energy electrons to practise the high-energy compound, FADH2, in addition to to a greater extent than NADH + H+.
Step 5. Enzymes rearrange bonding inside the four-carbon molecule to larn oxaloacetic acid, which combines amongst the acetyl-CoA to restart the Kreb's cycle.
Summary: The Kreb's Cycle produces 10 ATP in addition to molecules of FADH2 in addition to NADH + H+, which volition live used inward terminal oxidation. The CO2 is a waste materials production in addition to volition live expelled.
-Szent-Györgyi Albert won a Nobel Prize inward 1937 for his discoveries inward connective amongst biological oxidation
Terminal Oxidation
-it occurs on the cristae (inner membrane) of the mitochondria
-it is an electron carry chain, made upwards of a serial of coupled oxidation-reduction reactions
-each of the reactions releases energy, which is eventually used to shape ATP from ADP in addition to P.
Image from http://www.molvray.com/sf/exobio/images/electron_chain.jpg
Step 1: High energy electrons from NADH + H+ in addition to FADH2 operate inward the electron carry chain in addition to are passed from molecule to molecule, losing liberate energy inward a controlled stepwise manner.
Step 2: The liberate energy lost from the electrons is used to view hydrogen ions from the inner mitochondrial compartment to the outer mitochondrial compartment across the mitochondrial membrane. This creates an expanse of high hydrogen ion concentration on 1 side of the mitochondrial membrane in addition to a depression hydrogen ion concentration on the other side of the membrane. The trial is a concentration slope across the inner membrane creating a origin of potential energy, which is 1 time to a greater extent than comparable to the potential liberate energy of H2O held dorsum yesteryear a giant dam.
Step 3: The concentration slope is used every bit a origin of potential liberate energy to drive the chemiosmotic synthesis of ATP.
Step 4: Influenza A virus subtype H5N1 carrier poly peptide helps the hydrogen ions diffuse through a channel poly peptide opening inward the membrane. As the hydrogen ions diffuse from the expanse of high concentration to the expanse of depression concentration, the carrier poly peptide harnesses the kinetic liberate energy of the hydrogen ion to add together a high-energy phosphate grouping to ADP forming ATP, amongst the assistance of the enzyme ATP synthetase.
- carbohydrates (mainly glucose) in addition to fats are the master copy sources of energy
- proteins are rarely used for liberate energy - they are of import every bit edifice blocks for increment in addition to repair - they volition exclusively live converted to carbohydrates in addition to used for liberate energy if at that spot are no carbohydrates available.
2 types of respiration:
1. Aerobic: called biological oxidation, it needs O2
-in simplified version: C6H12O6 in addition to 6 O2 react inward the presence of enzymes to produced 6 H2O, 6 CO2 and energy.
2. Anaerobic: called fermentation, it doesn't quest O2, the overall procedure is simpler in addition to faster than biological oxidation, only produces much less energy.
GLYCOLYSIS
- this is the 1st pace of both aerobic in addition to anaerobic respiration
-it occurs inward the jail cellphone cytosol
-it doesn't quest O2, only it does require liberate energy (2 ATP)
Step 1. Energy is required to start the process, hence a molecule of glucose accepts ii high-energy phosphate groups from ii ATP molecules.
Step 2. The resulting intermediary molecule right away divides into two, three-carbon molecules called PGAL, each containing a high-energy phosphate group.
Step 3. Influenza A virus subtype H5N1 minute high-energy phosphate grouping is added to the three-carbon PGAL molecule in addition to ii NADH + H+ molecules are produced.
Step 4. Finally, the three-carbon PGAL molecules donate their high-energy phosphate to practise ATP in addition to the three-carbon pyruvate forms every bit the lastly products.
- 4 ATP molecules are produced inward glycolysis, only since 2 are required to start the process, the cyberspace gain is 2 ATP. This is non sufficient liberate energy to hold complex life systems, hence pyruvate (also called pyruvic acid) (which even hence contains energy) volition operate on into biological oxidation or fermentation, depending on the availability of O2
-if O2 is present, in addition to hence pyruvate enters the mitochondria:
AEROBIC RESPIRATION
- has 2 parts: biological oxidation and terminal oxidation
- requires O2
- occurs inward the mitochondria
Image from http://imagineannie.files.wordpress.com/2009/11/mitochondria1.jpg
Biological oxidation
-the commencement reaction occurs inward the outer membrane of the mitochondria:
pyruvate (CH3COCOOH) reacts amongst CoA (coenzyme A)to shape acetyl-CoA (CH2CO-CoA) yesteryear losing a carbon every bit CO2.
-acetyl-CoA volition operate inward the Kreb's Citric Acid Cycle in the mitochondrial matrix
Image from http://www.factmonster.com/images/cig/biology/03fig03.png
- the ikon to a higher house is a summary of ix enzyme-controlled reactions.
Step 1. Acetyl-CoA donates the two-carbon acetyl grouping to a four-carbon intermediary compound, oxaloacetic acid, to practise the six-carbon citric acid molecule.
Step 2. The high-energy electrons are oxidized to practise the energy-rich NADH + H+ molecule when the six-carbon chemical compound loses a carbon dioxide molecule to larn a five-carbon molecule.
Step 3. Influenza A virus subtype H5N1 minute molecule of NADH + H+ in addition to a molecule of ATP are produced when some other carbon dioxide molecule is released from the five-carbon molecule, which in addition to hence degrades to a novel four-carbon molecule.
Step 4. The four-carbon molecule is farther oxidized to transfer high-energy electrons to practise the high-energy compound, FADH2, in addition to to a greater extent than NADH + H+.
Step 5. Enzymes rearrange bonding inside the four-carbon molecule to larn oxaloacetic acid, which combines amongst the acetyl-CoA to restart the Kreb's cycle.
Summary: The Kreb's Cycle produces 10 ATP in addition to molecules of FADH2 in addition to NADH + H+, which volition live used inward terminal oxidation. The CO2 is a waste materials production in addition to volition live expelled.
-Szent-Györgyi Albert won a Nobel Prize inward 1937 for his discoveries inward connective amongst biological oxidation
Terminal Oxidation
-it occurs on the cristae (inner membrane) of the mitochondria
-it is an electron carry chain, made upwards of a serial of coupled oxidation-reduction reactions
-each of the reactions releases energy, which is eventually used to shape ATP from ADP in addition to P.
Image from http://www.molvray.com/sf/exobio/images/electron_chain.jpg
Step 1: High energy electrons from NADH + H+ in addition to FADH2 operate inward the electron carry chain in addition to are passed from molecule to molecule, losing liberate energy inward a controlled stepwise manner.
Step 2: The liberate energy lost from the electrons is used to view hydrogen ions from the inner mitochondrial compartment to the outer mitochondrial compartment across the mitochondrial membrane. This creates an expanse of high hydrogen ion concentration on 1 side of the mitochondrial membrane in addition to a depression hydrogen ion concentration on the other side of the membrane. The trial is a concentration slope across the inner membrane creating a origin of potential energy, which is 1 time to a greater extent than comparable to the potential liberate energy of H2O held dorsum yesteryear a giant dam.
Step 3: The concentration slope is used every bit a origin of potential liberate energy to drive the chemiosmotic synthesis of ATP.
Step 4: Influenza A virus subtype H5N1 carrier poly peptide helps the hydrogen ions diffuse through a channel poly peptide opening inward the membrane. As the hydrogen ions diffuse from the expanse of high concentration to the expanse of depression concentration, the carrier poly peptide harnesses the kinetic liberate energy of the hydrogen ion to add together a high-energy phosphate grouping to ADP forming ATP, amongst the assistance of the enzyme ATP synthetase.
Step 5. The high-energy electron is passed along the electron carry chain until the excess liberate energy is removed in addition to and hence it is combined amongst the excess hydrogen ions in addition to oxygen to shape water, which in addition to hence becomes a waste materials in addition to must live removed from the system.
For an animated sentiment see: The electron carry chain (http://vcell.ndsu.edu/animations/etc/movie-flash.htm) - don't worry close the names of all the cytochrome enzymes!
In summary, the oxidation of glucose is roughly 37 pct efficient in addition to produces all the liberate energy required for almost every type of cell. The consummate aerobic respiration of 1 molecule of glucose creates a maximum yield of 36 ATP molecules, every bit follows:
-Glycolysis = 4 ATP
- Kreb's cycle = 10 ATP
- Electron carry chain = 22 ATP
If at that spot is no O2 every bit a lastly acceptor, the whole organisation jams in addition to some other pathway must live followed:
FERMENTATION
-occurs when at that spot is no O2
-after glycolysis, at that spot are 2 pyruvates, 2 ATP's in addition to 2 NADH + H+
-the reaction occurs inward the cytosol
Image from http://www.bio.miami.edu/ cmallery/255/255atp/mcb8.5.fermentation.jpg
- no ATP is produced yesteryear fermentations, BUT NADH + H+ is used upwards in addition to NAD+ is regenerated in addition to returns to convey business office inward glycolysis reactions, hence glycolysis tin operate on (and gain some ATP).
Lactic acid fermentation occurs inward some bacteria (this is how nosotros brand yogurt in addition to cheese) in addition to inward most animals (this causes musculus pain)
Alcoholic fermentation occurs inward bacteria in addition to fungi (such every bit yeast). We brand purpose of it to brand beer, wine, etc
-in full general fermentation way that lots of liberate energy is lost. Fortunately, lactic acid tin live changed dorsum to pyruvate in addition to run through biological oxidation when O2 is available.
Metabolism of other Organic Compounds
- land carbohydrates are the major origin of liberate energy inward the cell, other organic compounds may operate inward these cycles (although this is non the commons situation!)
Lipids: obese acids are oxidized to shape many C2 molecules, which are converted into acetyl-CoA. Acetyl-CoA enters the Kreb's cycle. Glycerol is converted to PGAL, which enters glycolysis.
Proteins: NH2 is removed in addition to and hence resused or excreted. Remaining C chains are broken downward to many C2 molecules in addition to converted to acetyl-CoA, which enters the Kreb's cycle.
Nucleic acids N parts are reused or excreted. Pentose sugars are converted to PGAL, which enters glycolysis.
(Acetyl-CoA is an extremely of import intermediary, which is institute inward many catabolic in addition to anabolic reactions.)
Respiratory quotient (RQ) - Légzési hányados
-is a mensurate of the respiration (oxidation) rate
-determined yesteryear dividing the amount of CO2 evolved yesteryear the amount of O2 consumed. It is normally close 0.8-0.9 inward resting animals.
Lipids: obese acids are oxidized to shape many C2 molecules, which are converted into acetyl-CoA. Acetyl-CoA enters the Kreb's cycle. Glycerol is converted to PGAL, which enters glycolysis.
Proteins: NH2 is removed in addition to and hence resused or excreted. Remaining C chains are broken downward to many C2 molecules in addition to converted to acetyl-CoA, which enters the Kreb's cycle.
Nucleic acids N parts are reused or excreted. Pentose sugars are converted to PGAL, which enters glycolysis.
(Acetyl-CoA is an extremely of import intermediary, which is institute inward many catabolic in addition to anabolic reactions.)
Respiratory quotient (RQ) - Légzési hányados
-is a mensurate of the respiration (oxidation) rate
-determined yesteryear dividing the amount of CO2 evolved yesteryear the amount of O2 consumed. It is normally close 0.8-0.9 inward resting animals.
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