Chapter 7 Cellular Respiration Flashcards
Where is the Electron Transport Chain located? What is it consist of?
The ETC is located in the inner mitochondrial membrane.
It consists of mostly multi-protein complexes.
How is energy in NADH and FADH2 released in the ETC?
The energy is released in a series of redox reactions that occur as electrons pass through the chain of protein complexes to the final electron acceptor, oxygen, which is reduced to H2O.
What is the flow of electrons coupled with in the ETC?
The flow of electrons is coupled to the pumping of protons across the inner mitochondrial membrane, creating a concentration and an electrical gradient.
What does the electrochemical grandient provide?
Provides a source of potential energy used to drive the regeneration of ATP.
Describe how protons diffuse out from the intermembrane space and into the mitochondrial matrix.
Protons in the intermembrane space are able to diffuse down their electrical and concentration gradients through a protein channel called ATP Synthase into the mitochondrial matrix.
What are the two components of ATP Synthase?
Fo subunit forms a channel that rotates as protons pass throught it.
F1 subunit then uses this rotational energy to catalyze the synthesis of ATP.
Summarize the flow of energy in cellular respiration.
Most of the energy is transferred to electron carriers. These carriers donate electrons to the electron transport chain. That energy is used to pump protons across the inner membrane of the mitochondria. The energy of electron carriers is transformed into energy stored in prton electrochemical gradient. ATP Synthase converts the energy of the proton gradient to rotational energy, which drives the regeneration of ATP.
What was the net energy yield from the oxidative phosphorylation?
28 ATP
Where is the ETC located?
Inner mitochondrial membrane
What happens in the preparatory phase in glycolysis?
Glucose is prepared by the addition of 2 phosphate groups and an input of 2 ATP producing fructose 1,6 - biphosphate.
What happens in the cleavage phase in glycolysis?
Fructose 1,6 - biphosphate is split into two molecules of glyceraldehyde 3 - phosphate.
What happens in the payoff phase in glycolysis?
2 pyruvate molecules are formed and 2 NADH molecules are produced.
What happens in Acetyl-CoA Synthesis
In the presence of oxygen, pyruvate is transported into the mitochondrial mattix where it is converted to acetyl-CoA.
Pyruvate is oxidized to form acetyl group and CO2
The acetyl group is transferred to coenzyme A forming Acetyl-CoA, which is carried to the citric acid cycle.
2 NADH and 2CO2 are produces per glucose molecule.
Where does the Acetyl-CoA Synthesis take place?
Mitochondrial matrix
What stage does gluclose become completely oxidized?
In the citric acid cycle.
What molecule is regenerated at the end of the citric acid cycle?
Oxaloacetate is regenerated at the end of the citric acid cycle.
Where does the energy in the bonds of acetyl-CoA go?
The chemical energy in the bonds of acetyl-CoA is transferred to ATP by substrate level phosphorylation and to the electron carriers NADH and FADH2.
What is the first step of the citric acid cycle?
The two xarbon lart of Acetyl-CoA is added to oxaloacetate for citrate.
What happens in steps 3 and 4 in the citic acid cycle?
The oxidation of carbon atoms to produce CO2 is coupled with the reduction of NAD+ and FAD to their reduced forms.
What is the net energy yield of the citric acid cycle per glucose molecule?
6NADH 2FADH 2ATP and 2 CO2
What are the 3 ways to obstruct the process of oxidative phosphorylation?
- Block the ETC. E.g rotenone, cyanide, carbon monoxide.
- Block the flow of H+ through the ATP Synthase, e.g. The antibiotic Oligomycin.
- Make the membrane leaky to H+ e.g. Dinitriophenol.
Why was dinitriophenol used as a diet pill in the 1930s?
DNP would make you burn more glucose to produce a certain concentration of ATP.
What is brown fat? What is its functions?
Brown fat is a special type if fat tissue associated with the generation of heat.
In brown fat, the cells the packed with mitochondria.
The inner mitochondrial membrane contains a protein, which allows H+ to flow back down its concentraion gradient without generateing ATP, but generating heat.
How do cells regulate cellular respiration?
The level of ATP in the cell is an indicator of how much energy a cell has available. When ATP levels are high, the cell DOWN REGULATES the pathways leading to ATP synthesis.
When ATP levels are low or ADP levels are high, the cell UP REGULATE the pathways that lead to ATP synthesis.
