respiration

Glycolysis is the first stage of anaerobic and aerobic respiration. It occurs in the cytoplasm and is an anaerobic process.

Glycolysis involves the following stages:

• phosphorylation of glucose to glucose phosphate, using ATP
• production of triose phosphate
• oxidation of triose phosphate to pyruvate with a net gain of ATP and reduced NAD.

•  pyruvate from glycolysis enters the mitochondrial matrix by active transport.
• pyruvate is oxidised to acetate, producing reduced NAD in the process
• acetate combines with coenzyme A in the link reaction to produce acetylcoenzyme A
• acetylcoenzyme A reacts with a four-carbon molecule, releasing coenzyme A and producing a six-carbon molecule that enters the Krebs cycle

• in a series of oxidation-reduction reactions, the Krebs cycle generates reduced coenzymes and ATP by substrate-level phosphorylation, and carbon dioxide is lost

• in the matrix
• 2C acetyl co A with 4C moleule to form a 6C compound 
• 6C compound loses CO2 and hydrogen (which reduces nad to. nadh2) to convert to 5C compound
• as 5C converts to a 4C compound, it losses hydrogen to reduce 2 NAD to NADH2, 1 FAD to FADH2 and releases 1 ATP.
• cycle goes round

• removal of hydrogen/ dehydrogenation 
• by enzymes/ dehydrogenases
• H accepted by NAD / reduced NAD formed 
• in krebs cycle FAD used as well

If respiration is only anaerobic, pyruvate from glycolysis can be converted to ethanol or lactate using reduced NAD. The oxidised NAD produced in this way can be used in further glycolysis

If respiration is aerobic, pyruvate from glycolysis enters the mitochondrial matrix by active transport.

• pyruvate is oxidised to acetate, producing reduced NAD in the process
• acetate combines with coenzyme A in the link reaction to produce acetylcoenzyme A
• acetylcoenzyme A reacts with a four-carbon molecule, releasing coenzyme A and producing a six-carbon molecule that enters the Krebs cycle
• in a series of oxidation-reduction reactions, the Krebs cycle generates reduced coenzymes and ATP by substrate-level phosphorylation, and carbon dioxide is lost
• synthesis of ATP by oxidative phosphorylation is associated with the transfer of electrons down the electron transfer chain and passage of protons across inner mitochondrial membranes and is catalysed by ATP synthase embedded in these membranes (chemiosomotic theory)
• other respiratory substrates include the breakdown products of lipids and amino acids, which enter the Krebs cycle.

·       oxidation of/removal of electrons / removal of H+

·       from pyruvate/

·       acetyl CoA / 6 carbon compound; (credit oxidative decarboxylation)

·       substrate level production of ATP / ATP produced in Krebs cycle;

·       production of reduced NAD / FAD (allow they take up hydrogen);

·       in matrix of mitochondria;

·       electrons fed into electron transport chain / used in oxidative

·       (Electrons) pass along carriers/through electron transport chain/through series of redox reactions; 

·       Energy released; 

·       Protons move into intermembrane space;

·       ADP/ADP + Pi;  

·       ATP synthase;

·      NAD/FAD reduced / hydrogen attached to NAD/FAD; 

·      H+ ions/electrons transferred from coenzyme to coenzyme/carrier to carrier / 

·      series of redox reactions; 

·      energy made available as electrons passed on; 

·      energy used to synthesise ATP from ADP and phosphate /  using ATPase; 

·      H+/ protons passed into intermembrane space; 

·      H+/ protons flow back through stalked particles/enzyme;  

·      NAD/FAD reduced / hydrogen attached to NAD/FAD;

·      ETC on cristae / inner membrane;

·      H+ ions/electrons transferred from coenzyme to coenzyme/carrier to carrier / series of redox reactions;

·      energy made available as electrons passed on;

·      H+ / protons passed into intermembrane space;

·      H+ / protons flow back through stalked particles/enzyme;                                                                                                                                

·      energy used to synthesise ATP from ADP and phosphate / using ATPsynthase;

·      oxygen is terminal/final electron acceptor;

combines with electron and hydrogen (to form water);

·      removal of hydrogen/dehydrogenation;

·      by enzymes/dehydrogenases;

·      H accepted by NAD/reduced NAD formed;

in Krebs cycle, FAD (used as well);

·      larger surface area for electron carrier system / oxidative phosphorylation; 

provide ATP / energy for contraction;