18.2 The link reaction Flashcards
In eukaryotic cells, where do aerobic reactions of respiration occur?
In mitochondria
What is the function of the outer mitochondrial membrane?
Separate contents of mitochondrion from the rest of the cell, creating a cellular compartment w/ ideal conditions for aerobic respiration
What does the matrix contain?
Enzymes for link reaction + krebs cycle
Mitochondrial DNA
What does the inner mitochondrial membrane contain?
Electron transport chains and ATP synthetase
What are cristae? What is their function?
Extensions of the inner mitochondrial membrane - Increase SA for oxidative phosphorylation
What is the function of the intermembrane space?
Where proteins are pumped by electron transport chains.
The space is small so concentration builds up quickly.
What is the first step of aerobic respiration?
Oxidative decarboxylation, also known as link reaction
Why is oxidative dexarboxylation also referred to as the ‘Link Reaction?
It links anaerobic glycolysis in cyotoplasm w/ aerobic respiration in mitochondria
What are the 4 stages of the link reaction?
- Pyruvate enters mitochondrial matrix by active transport via carrier proteins
- Pyruvate undergoes oxidative decarboxylation - CO2 removed (decarboxylation) and H is removed (oxidation)
- Removed H are accepted by NAD to form reduced NAD (NADH)
- Resulting 2-C acetyl group is bound by coenzyme A to from acetylcoenzyme A
What is the function of acetyl CoA?
Deliver 2-C acetyl group into Krebs cycle, the next stage of respiration
What is the reduced NAD used for?
Oxidative phosphorylation to synthesise ATP
What happens to the CO2 released when 3-C pyruvate turns into 2-C acetyl?
Diffuse away + removed as metabolic waste
In autotrophs, used as raw material for photosynthesis
