Module 1 Lecture 3 - Cellular Metabolism: Respiration Flashcards
How many enzymatic steps are involved in glycolysis
10 enzymatic reactions
What is the final result of glycolysis
Glucose broken into 2 3-carbon molecule (pyruvate)
How many pyruvate molecules are made at the end of glycolysis?
2 pyruvate molecules
How much ATP is made in glycolysis?
A net of 2 ATP; some was used to continue the glycolysis process
How much NADH is made in glycolysis?
2 NADH
Where does glycolysis take place and why?
Happens in the cytosol; the cytosol carries many intermediary metabolic enzymes
What is McArdle’s Disease? How does it affect cellular respiration
The absence of an enzyme that converts glycogen to glucose; without glucose glycolysis cannot happen
At the end of glycolysis where is most of the energy in?
The 2 3-carbon molecule (Pyruvate)
What does pyruvate decarboxylation mean?
It means to remove a carbon
Where does pyruvate decarboxylation take place?
In the mitochondrial matrix
How many pyruvate molecules go through pyruvate decarboxylation?
2
What is carbon removed in the form of in pyruvate decarboxylation?
CO2 through the cardio-respiratory system
What is pyruvate catalyzed into?
Acetyl-CoA (2 carbon molecule)
What is the final result of pyruvate decarboxylation?
2 CO2 and 2 NADH
Is there any ATP made in pyruvate decarboxylation?
No
What is the purpose of NADH and FADH2
They carry high energy electrons with the purpose of releasing them in the ETC
Where do the acetyl-CoA go after decarboxylation?
TCA/Citric Acid/Krebs Cycle
Where does Krebs cycle take place?
Matrix of Mitochondria
How many reactions take place in the Krebs cycle?
8 reactions
What two molecules make citric acid in the Krebs Cycle?
Oxaloacetate and acetyl-CoA
How is Acetyl-CoA used up in the Krebs cycle?
The 2 carbon Acetyl-CoA combines with the 4 carbon Oxaloacetate; the 2 carbons are lost in the cycle
What are the carbons that are lost turned into? (Krebs)
CO2
Where does the CO2 go from once it leaves the matrix (pyruvate decarbox. and krebs)?
Outside the cell => blood => lungs => expelled out
Oxygen is used when forming CO2 in these reactions. Where does it come from?
The oxygen comes from the reactions, not from inhaling it in
Which reactions are the carbons lost in?
d-isocitrate => alpha-ketogluterate & alpha-ketogluterate => Succinyl-CoA
Which reactions are NADH made in (Krebs Cycle)?
d-isocitrate => alpha-ketogluterate & alpha-ketogluterate => Succinyl-CoA & Malate => Oxaloacetate
Which reactions are FADH2 made (Krebs Cycle)?
Succinate => Fumarate
Through which process is ATP made in the Krebs cycle?
Substrate-level phosphorylation
How is GTP made?
Enzyme CoA is removed from Succinyl-CoA and replaced with a phosphate group. The phosphate group is then used to make GDP into GTP
How is ATP made in the Krebs Cycle?
Indirectly; GDP is turned into GTP which is a similar energy molecule to ATP but cannot be used. It (GTP) then gives its phosphate to ADP to make ATP
What does the energy transfer process from GTP to ADP look like? (Reaction process)
ADP + GTP => <= ATP + GDP
What is the purpose of removing hydrogens and adding them to NAD+ and FAD?
By removing these hydrogens and attaching them to these energy carriers, they can be used in the ETC to generate ATP
After the Krebs cycle where is the energy now that the carbons are gone?
Energy is being held by the molecule carriers (NADH and FADH2)
What does one cycle of Acetyl-CoA in the Krebs cycle make?
3 NADH, 1 FADH2, 1 ATP
How many times is the Krebs cycle used?
Twice
Where do the energy carriers go after the Krebs Cycle?
Electron Transport Chain
Where does the ETC take place?
Inner mitochondrial membrane
What do the energy molecule carriers do in the ETC?
They release high the high energy electrons which in turn releases free energy
Why are proteins anchored on the inner mitochondrial membrane?
They allow for much more energy to be generated
How many protein complexes are there?
4; 5 if we count ATP synthase as complex 5
What releases the high energy electrons in the ETC
Hydrogens on NADH and FADH2
What can the free energy released by the electrons be utilized for?
Hydrogens from NADH and FADH2 can harness that energy to move across the protein complexes
Where do the hydrogens move from and go to in the ETC when they harness enough energy?
Move from the matrix, through the complex in the inner mitochondrial membrane to the intermembrane space
Which complex is the only one that does not span the entire inner membrane?
Complex 2
Which complex does NADH release its electron and subsequently its hydrogen?
Complex 1
Which complex does FADH2 release its electron and subsequently its hydrogen?
Complex 2
Why does NADH make more ATP than FADH2
FADH2 drops its electron off at complex 2 which has to shuttle over to complex 3 to let the hydrogen through; it contributes less than NADH to passing hydrogens through the complex
Where do the electrons finally go at the end of the ETC
Oxygen; the final electron acceptor
Where do the hydrogens accumulate?
Inner membrane space to go through ATP Synthase
How does ATP synthase make ATP?
The high concentration of H+ ions move from the inner membrane space to the matrix; this allows ATP synthase to combine ADP with inorganic phosphate
What is the term used for allowing the passage of H+ ions through ATP synthase?
Chemiosmosis
How much ATP does one NADH molecule make? How many NADH molecules are overall made?
2-3 ATP (2.5 on average); 10 NADH molecules were made in cellular respiration
How much ATP does one FADH2 molecule make? How many FADH2 molecules were made in cellular respiration?
1-2 ATP (1.5 on average); 2 FADH2 molecules
What link does NADH and FADH2 represent
The link between TCA and ETC because after being converted back to NAD+ and FAD they can go and collect more hydrogens
If cellular respiration occurred without oxygen how far could it go?
It could only go till Glycolysis because pyruvate instead of being converted into ACoA it turns into lactate
How does lactate work in anaerobic respiration?
It uses up the NADH and turns it back into NAD+ so that molecules can go back to glycolysis and repeat the same process
How much energy is produced in anaerobic respiration? Also why is it bad?
2 ATP; it’s bad because not enough energy is being made plus lactate is toxic to our bodies
Could our bodies make energy if there was no glucose?
Yes; fatty acids (fatty acid beta oxidation) and in severe cases proteins too
