3.3 Respiration Releases Chemical Energy In Biological Processes Flashcards
(57 cards)
Overall equation for aerobic respiration
Glucose + 6oxygen atoms –> 6carbon dioxide + 6water molecules + 38ATP
What is the theoretical and usual range of ATP yielded during aerobic respiration of 1 glucose molecule?
Theoretical- 38 ATP
Usual - 32-38 ATP
Name 4 stages of aerobic respiration in order
Glycolysis
Link reacion
Krebs cycle
Electron transport chain
Where does glycolysis occur?
Cytoplasm
Does glycolysis require oxygen
No
Define aerobic respiration
Release of large amounts of energy as ATP from the breakdown of molecules where oxygen acts as the terminal election acceptor
Define anaerobic respiration
Release of relatively little energy as ATP from the breakdown of molecules in the absence of oxygen by substrate level phosphorylation.
Steps during glycolysis
• glucose is phosphorylated to produce glucose diphosphate by the use of 2 ATP
• Glucose diphosphate splits to 2 triose phosphate
• each triose phosphate is dehydrogenated as 2 NADs are reduced to NADH
• 4 ATP are produced by substrate-level phosphorylation
• 2 pyruvate molecules are produced
How many C in glucose diphosphate
6
How many C in triose phosphate
3
How many C in pyruvate
3
Define dehydrogenation
the removal of hydrogen atoms, performed by dehydrogenase enzymes.
Net yield of ATP during glycolysis and how
2 ATP
•4 produced but 2 are used to phosphorylate glucose
Where does Link reaction occur
Mitochondrial matrix
What does pyruvate have to do in order so undergo link reaction
Diffuse into the mitochondria
Does link reaction require oxygen?
Yes
Steps of the Link reaction
• pyruvate diffuses into the mitochondrial matrix
• pyruvate is dehydrogenated - the hydrogen released reduced NAD
• pyruvate is decarboxylated and so carbon dioxide is removed and acetyl is produced
• Coenzyme A is added to form acetyl CoA
Why does glucose have to be broken down to pyruvate before it enters the mitochondrion?
• glucose is too big to diffuse into the mitochondrion
• mitochondrion don’t possess the enzymes needed for glycolysis
Define decarboxylation
the removal of carbon dioxide, performed by decarboxylase enzymes.
Does krebs cycle require oxygen
Yes
Describe 1 cycle of Krebs cycle
• Acetyl CoA joins to [4C] acid to produce [6C] acid
• the [6C] acid is decarboxylated releasing 1 molecule of CO2 and dehydrogenated, reducing 1 NAD molecule
• the resulting [5C] acid is decarboxylated releasing 1 molecule of CO2 and dehydrogenated, reducing 2NAD AND 1FAD molecules, ATP is produced directly by substrate level phosphorylation
• resulting [4C] acid combines with acetyl CoA and the cycle continues
Does the electron transport chain require oxygen?
Yes
Where does the Electron Transport Chain occur?
Cristae - inner membrane of mitochondrion
Describe what happens in the Electron Transport Chain
• reduced NAD carries hydrogen atoms to the Electron Transport Chain
• the NADH is then oxidised and the hydrogen atoms split into protons and electrons
• the electrons are donated to the first electron carrier in the Electron Transport Chain and the protons remain in the matrix
• the electrons provide energy for the first proton pump - this energy is used to pump protons into the inter-membrane space
• the electrons pass along the chain of carrier molecules providing energy for each pump in turn
• the protons accumulate in the inter-membrane space as the inner membrane is impermeable to protons
• the concentration of protons becomes higher in the inter-membrane space and an electrochemical gradient is built up
• stalked particles contain the enzyme ATP synthetase
• protons diffuse back into the matrix through the stalked particle and their electrical potential energy is used to create ATP
• at the end of the chain the electrons combine with the protons and oxygen to form water - oxygen is the final electron acceptor
