Welcome All! Today’s post will be focused on the Link reaction and TCA. So we all  know what glycolysis is and what occurs during glycolysis.

1. To the end of glycolysis, pyruvate undergoes a Link reaction and enters the inside of the mitochondria as Acetyl-Coenzyme A.

2.The link reaction occurs in the mitochondrial matrix is important between the metabolic pathways of glycolysis and the Krebs cycle.

3.The Krebs cycle is a series of reactions that generate energy by way of aerobic respiration.

4.For every glucose molecule that enters glycolysis two pyruvate molecules are produced thus each stage of this cycle occurs twice.

5.A 2C compound enters the cycle, is combined with a 4C compound and forms a 6C compound.

6.2 carbons are removed as carbon dioxide at different stages. This is known as decarboxylation which eventually regenerates the 4C compound and the cycle continues. 

7.The transfer of energy from the conversion of one molecule to another form of the molecule leads to the immediate production of ATP. 

Below is a diagram of the Krebs cycle.


Key Points to Remember

1.      A different enzyme controls each stage

2.      In some cases intermediate compounds are named according to their parent acids  

3.      Reduced forms of NAD & FAD can be written as NADH, NADH2 or NADH/H+

4.      Substrate level phosphorylated occurs when succinyl coenzyme A is converted to succinate

5.      At two points of the cycle water enters as a reactant.

Electron Transport Chain

Below is a diagram of the Electron Transport Chain.


Attached below is a really helpful animation on the electron transport chain.

Using the chemiosmotic hypothesis, explain how ATP is generated in the mitochondria.

·         NADH & FADH

·         Inner membrane of mitochondria

·         NADH & FADH lose an electron- have a high transfer potential

·         Electron transport chain- 4 cytochrome electron phases

·         Transfer from E1 to E2 to E3 to E4

·         Energy being released

·         Energy used to pump protons

·         Matrix to inner membrane space

·         Complex 1,3, 4 use energy to pump protons to the inner membrane

·         Inner membrane impermeable

·         ATP Synthase- undergoes a conformational change

·         Uses energy that flows into the system of H+ to allow the phosphorylation of ATP

·         ADP + P1 ==> ATP

·         Fully oxidize glucose ==> Products CO2 + H2O

·         Complex 4 makes water

Thanks again for viewing my blog! 


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