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Respiration - Coggle Diagram
Respiration
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Aerobic respiration:
Uses oxygen Is a complete breakdown of glucose
Releases a large amount of energy Is a two-stage process
Is represented by the balanced equation: C6H12O6 + 602 ⟶ 6CO2 + 6H20 + energy
Stages in aerobic respiration:
Stage 1
Does not use oxygen (it is anaerobic)
Takes place in the cytosol of the cell
Releases very little energy
Splits glucose into two three-carbon molecules.
Stage 2
Uses oxygen (it is aerobic)
Takes place in the mitochondrion
Releases a large amount of energy
Converts the three-carbon molecules formed in stage 1 to carbon dioxide and water.
Anaerobic respiration (or fermentation):
Does not use oxygen Is a partial breakdown of glucose
Releases a small amount of energy Is a stage 1 process
Takes place in the cytosol Is represented by the word equations:
Glucose -> 2 lactic acid + some energy
Glucose > 2 ethanol + 2 carbon dioxide + some energy
Stage 1
In anaerobic respiration is the same as stage 1 in aerobic respiration, except that the three- carbon molecules are converted to:
Lactic acid in lactic acid fermentation (takes place in some bacteria and human muscle)
Ethanol and carbon dioxide in alcohol fermentation (takes place in some bacteria and yeast).
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A large range of micro-organisms, especially bacteria and yeast, are used in industry to carry out different anaerobic or fermentation reactions.
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In glycolysis:
Glucose is split into two molecules of pyruvic acid (or pyruvate)
No oxygen is used
ATP and NADH are formed.
Stage 2
In the presence of oxygen, stage 2 proceeds in the mitochondrion. Stage 2 involves both Krebs cycle reactions and the electron transport system.
Pyruvic acid loses carbon dioxide and high-energy electrons (in the form of NADH), forming acetyl CoA.
In Krebs cycle:
Acetyl CoA goes through a cycle of reactions
Acetyl CoA is converted to carbon dioxide and hydrogen
High-energy electrons and protons (H+) are released to form several NADHS
ADP is converted to ATP.
In the electron transport systems (located on the inner membrane of the mitochondrion):
NADH releases high-energy electrons
The electrons are passed from molecule to molecule along the system
The electrons release energy as they pass along
The energy is used to form ATP
At the end of the system, low-energy electrons combine with oxygen and hydrogen to form water.
There are two forms of anaerobic respiration:
In lactic acid fermentation, glycolysis is followed by the conversion of pyruvic acid to lactic acid
In alcohol fermentation, glycolysis is followed by the conversion of pyruvic acid to ethanol and carbon dioxide.
To prepare alcohol:
Mix glucose and water
Boil the solution
Add yeast
Cover with oil
Leave in a warm place.
To show the production of alcohol (Note: This reaction should no longer be carried out):
Add acidified potassium dichromate
Warm in hot water If the colour turns from orange to green then alcohol is present.
Aerobic respiration involves both stage 1 (anaerobic, low energy release) and stage 2 (aerobic, high-energy release).
Anaerobic respiration only involves stage 1 and is a low-energy release process.
To show the production of ethanol:
Add potassium iodide
Add sodium hypochlorite
If pale yellow crystals form, ethanol is present.