Aerobic Respiration
- Created by: beccalhogg
- Created on: 25-10-16 22:22
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- Aerobic Respiration
- Glycolysis
- In cytoplasm
- 6C glucose is converted into 2 lots of 3C pyruvate
- Glucose is converted into phosphorylated sugar which activates the sugar - i's more reactive
- The 6C hexose sugar is split into 2 lots of 3C triose sugars
- The 2 molecules of 3C triose sugars are oxidated (H are removed) into 2 lots of 3C pyruvate
- Net gain of 2ATP and 2NADH2
- Link Recation
- Matrix
- Pyruvate reacts with CoA to produce AcCoA
- The AcCoA contains 2C from the pyruvate molecule
- The AcCoA reacts with a 4C molecule to form a 6C product which enters the Krebs Cycle
- CoA is regenerated and can be reused
- Krebs Cycle
- Matrix
- A series of reactions where the 6C molecule is oxidised by removing H and produces CO2
- H is accepted by NAD and FAD, the reduced coenzymes (NADH2 and FADH2) areused to make ATP.
- The oxidation of 6C molecule makes CO2 and reforms a 4C molecule to react with more 2C from AcCoA
- A small amount of ATP is made from Krebs but main product is reducing power of NADH2 and FADH2
- 1 turn of the Krebs cycle makes 1ATP, 3NADH2, 1FADH2
- Don't forget there are 2 turns of the krebs cycle so these will double
- ETC
- Cristae
- Reducing power produced by Krebs is used to generate lots of ATP by oxidative phosphorylation
- NADH2 and FADH2 travel to inner mitochondrial membrane where they reduce the first molecule in a chain of electron carriers
- NADH2 or FADH2 lose H2 so NAD/FAD are made and can be reused
- The H2 lost is dissociated into 2H+ and 2e- where the 2e- gives up energy in a series of reduction and oxidation reactions
- The electrons pass from proteins on the inner mitochondrial membrane which are arranged in order of decreasing energy levels
- Some energy lost by the electron in this process is conserved in the making of ATP
- ADT + P = ATP -- this is a phosphorylation reaction
- Loss of energy by electrons in oxidations and the synthesis of ATP = oxidative phosphorylation
- Electrons coming off the ETC are accepted by O2 and joined by H+ to make water
- Without O2 to accept e- all respiratory stages would get stuck in their reduction state and ATP production in mitochondria would stop
- NADH2 and FADH2 travel to inner mitochondrial membrane where they reduce the first molecule in a chain of electron carriers
- Respiratory Substrates
- Fats
- First reserve
- Fats are hydrolysed by lipase into 3 fatty acids and a glycerol
- The long chain fatty acids are split into 2C fragments which enter respiratory pathway as AcCoA
- Glycerol enters pathway via triose phosphate
- Carbohydrates
- First choice
- The polysaccharides are hydrolysed to monosaccharides
- In plants: starch turns to glucose
- In animals: glycogen turns to glucose
- Proteins
- Last reserve
- Only used during prolonged starvation
- Proteins are hydrolysed into constituent amino acids and then deaminated
- The left over carbon compound, a keto acid, enters respiratory pathway as different molecules depending on original amino acid
- Fats
- Chemiosmosis
- How ATP is made
- ATPase is the enzyme that breaks ATP down into ADP and P
- NADH2 splits into NADH2 and 2e-, the e- pass down a chain of e- carriers, releasing energy
- The energy is used o pump protons (operate proton pump) from the matrix, out, causing an electrochemical gradient to develop across cristae
- The protons move down a concentration gradient, into the matrix at the site of ATP synthase
- As the protons move back in, the H+ release energy, used to combine ADP and P to form ATP
- How ATP is made
- Glycolysis
- In first two stages of Krebs decarboxylation is where CO2 is removed and dehydrogenation is where H is removed
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