Aerobic Respiration Flashcards
What is the first stage of aerobic respiration
Glycolysis
What is glycolysis
The process by which glucose is broken down into two molecules of pyruvate
Why does glycolysis take place
To release energy in the form of ATP, that the cells can use
Where does glycolysis take place
- in the cell cytoplasm
What are the four stages of glycolysis
1) Phosphorylation (of glucose)
2) Splitting of the hexose 1,6-bisphosphate
3) Oxidation of triose phosphate
4) Conversion of triose phosphate to pyruvate
What is the start product of glycolysis
Glucose (6C)
What is the end product of glycolysis
2 Pyruvates (3C)
Describe glycolysis
1) starts with glucose (6C)
2) Glucose is phosphorylated by ATP which leaves ADP as a product as well as Glucose-6-P
3) Glucose-6-P is unstable and breaks down to fructose-1-P
4) Fructose-1-P is phosphorylated, making Hexose 1,6-bisphosphate as well as ADP
5)Hexose 1,6-bisphosphate is also an unstable molecule so this breaks down to 2 Triose phosphate (3C) molecules
6) Triose phosphate is oxidised (looses a H) forming 2 Intermediate compound s(3C) molecules which reduces 2 ADP and 2 NAD to form 2 ATP and 2 NADH
7) The intermediate compounds (3C) is also oxidised to form 2 Pyruvate (3C) molecules which reduces another 2 ADP molecule to 2 ATP
What are the reactants in glycolysis, and how many of each molecule
- 2 ATP
- 2 NAD
- 4 ADP
- Glucose
What are the products in glycolysis, and how many of each molecule
- 4 ATP
- 2 ADP
- 2 NADH
- 2 Pyruvate
Name and describe the 3 types of ATP production
1) Photophosphorylation
- occurs in the chlorophyll during photosynthesis (requires co-enzyme NADP)
2) Oxidative phosphorylation
- occurs in the mitochondria during the electron transport chain (part of respiration requires co-enzymes NAD or FAD —> both shuttle hydrogen)
3) Substrate-level phosphorylation
- when phosphate groups are transferred from donor molecules to ADP
What is the mitochondria
The site of aerobic respiration
What are the parts of the mitochondria
1) Outer membrane
2) Inner membrane
3) Inter membrane space
4) Crista
5) Matrix
What is the role of the outer mitochondrial membrane
- a barrier that stops large molecules from entering the mitochondria (but it allows pyruvate in)
What is the role of the inner mitochondrial membrane
- a barrier which prevents many small molecules from the cytoplasm from entering (impermeable to most small ions) the matrix
- contain electron carriers and ATP synthase molecules
What is the role of the inter membrane space
- act as a temporary energy store before the energy is used to make ATP
What is the role of the matrix
- contains the enzymes of the Krebs cycle
-site of Link and Kreb reaction
What is the role of the crista
- highly folded which creates a large surface area to hold electron carriers and ATP synthase molecules
How is ATP generated in respiration
1) Substrate level phosphorylation
2) Oxidative phosphorylation ( has to have a H+ pump/ electron chain)
What is the Link reaction
The reaction where Pyruvate gets decarboxylated and dehydrogenated
Where does the Link reaction take place
- the mitochondrial matrix
Describe the Link reaction
1) Pyruvate (3C) undergoes decarboxylation and looses a CO2 molecules
2) Pyruvate also undergoes dehydrogenation and the H+ ion it looses is used to reduce NAD forming NADH
3) the decarboxylation and dehydrogenation of pyruvate forms an acetate (2C) group
4) this acetate group (2c) combines with coenzyme A (CoA) to become acetyl CoA which goes into the Krebs reaction
What is the Krebs cycle
- a series of enzyme-catalysed reactions that oxidise the acetyl CoA from the link reaction to two molecules of carbon dioxide whilst also conserving energy by reducing the coenzymes NAD and FAD
Where does the Krebs cycle take place
- the mitochondrial matrix
Describe the Krebs cycle
1) the acetate in the acetyl group (2C) combines with oxaloacetate (4C) forming citrate (6C)
2) this citrate (6C) is then decarboxylated and dehydrogenated, forming a 5C compound, NADH and CO2
3) this 5C compound is further decarboxylated & dehydrogenated producing a 4C compound, NADH and CO2
4) this 4C compound combines temporarily to CoA and then it is released. Substrate- level phosphorylation takes place producing ATP
5) the 4C compound is dehydrogenated producing a different 4C compound and FAD2H
6) the 4C molecule’s atoms are rearranged catalysed by an isomerase enzyme, and further dehydrogenation takes place, producing NADH
7) the 4C molecule is regenerated to oxaloacetate so the cycle can continue.
What are the reactants in the Link reaction
- Pyruvate
- NAD
- CoA