Energy transfers- Respiration Flashcards
What is the purpose of respiration?
To produce ATP.
What are the four stages of respiration?
Glycolysis, the link reaction, the krebs cycle, and oxidative phosphorylation.
Where does glycolysis take place?
The cytoplasm of the cell.
Describe the process of glycolysis.
- Substrate-level phosphorylation - Glucose has two phosphate groups added to it from two ATP molecules.
- This splits into two molecules of triose phosphate (TP).
- These are oxidised by two NAD molecules to form two molecules of pyruvate, two molecules of NADH, and four molecules of ATP.
What are the net products of glycolysis per molecule of glucose?
2 NADH
2 pyruvate
2 ATP
Where does the link reaction take place?
In the mitochondrial matrix
Describe the process of the link reaction.
- A carbon is removed from pyruvate in the form of carbon dioxide. This reaction is catalysed by decarboxylase enzymes.
- Two hydrogen atoms are removed by NAD which forms NADH, leaving acetate.
- Coenzyme A combines with acetate to form acetyl CoA
What are the net products of the link reaction per glucose molecule?
2 Acetyl CoA
2 CO2
2 NADH
Where does the krebs cycle take place?
In mitochondrial matrix
Describe the process of the Krebs cycle.
- Acetyl group from acetyl CoA combines with oxaloacetate to form a 6 carbon molecule.
- Citrate undergoes decarboxylation and dehydrogenation to form a 5-carbon molecule. 1 CO2 and 1 NADH produced.
- 5 carbon molecule undergoes decarboxylation and dehydrogenation to form a 4-carbon molecule. 1 CO2 and 1 NADH produced.
- 4-carbon molecule undergoes dehydrogenation and ATP synthesis occurs. 1 FADH and 1 ATP produced.
- 4-carbon molecule is reduced to regenerate oxaloacetate. 1 NADH produced.
What are the net products of the Kreb’s cycle per glucose molecule?
2 ATP
2 NADH
2 FADH
Where does oxidative phosphorylation take place?
The inner mitochondrial membrane of the cristea.
Describe the process of oxidative phosphorylation.
- NADH and FADH transfer H+ and e- into the mitochondrial matrix.
- High energy electrons are passed to an electron carrier from NADH and FADH.
- The electrons are transferred along a series of electron carrier molecules in the electron transport chain, releasing energy as they are transferred.
- The energy is used to transport protons from the mitochondrial matrix to the intermembranal space. This creates a diffusion gradient.
- They then diffuse back into the mitochondrial matrix through ATP synthase, which catalyses the synthesis of ATP from ADP and Pi.
- Oxygen is the final electron acceptor, and combines with electrons and proteins to form water, helping to maintain a proton gradient.
What are the net products of oxidative phosphorylation per molecule of glucose?
30-32 ATP
Water
Give the process of anaerobic respiration.
Glucose undergoes glycolysis to form 2 molecules of pyruvate, which are then reduced to form two molecules of lactate and 2 NADH.
