Cell Respiration Flashcards
Three types of metabolic pathway regulation
- Gene Regulation
- Cell-Signaling Regulation
- Biochemical Regulation (feedback inhibition)
Feedback Inhibition
Product of pathway inhibits early steps to prevent over-accumulation of product
3 stages of Glycolysis
- Energy investment
- Cleavage
- Energy liberation
Energy investment
Glucose turns into fructose-1, 6 biphosphates.
Two ATP are broken down in this process
Cleavage
F-1, 6BP turns into two G3P
Energy Liberation
G3P turns into two pyruvate molecules.
2 NADH and 4 ATP produced
Net yield of glycolysis
2 ATP
Phosphofructokinase
What inhibits it
catalyzes the third step in glycolysis
A high level of ATP inhibits its function.
Pyruvate breakdown
- Transported into the mitochondrial matrix
- Broken down by pyruvate dehydrogenase (CO2 removed from each)
- The remaining acetyl group forms acetyl-CoA
- Yields 1 NADH per pyruvate
What is a redox reaction? Why do C-H bonds have more potential energy than C-O bonds?
Redox reactions are when a molecule either gains or loses electrons. C-H bonds do not have the same electron pull as O in C-O bonds, so more energy is needed to pull C-H apart
Explain the purpose of NADH and FADH2 in respiration (and fermentation).
They are electron transporters and acceptors.
Explain how oxygen plays a critical role in respiration; what makes it a good molecule to serve as the final electron acceptor?
O2 is an electron acceptor. It is a good acceptor because it is very common within the cell, and easily can bind to excess protons.
Describe situations when cell respiration would be used by cells and when fermentation would be used.
Cell respiration: aerobic
Fermentation: anaerobic
How much ATP does fermentation yield?
2 ATP
Differences between Lactic acid and Ethanol fermentation
- Pyruvate reduced to lactate
- Ethanol: can occur with or without O2
- Pyruvate is broken down in both
- Acetaldehyde is in EF. Reduced to make ethanol
- Both processes have NADH oxidizing to NAD+
