BIOC405 LECTURE 19 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
T or F: pyruvate is a key node in several catabolic and anabolic processes
T
What are the 2 fates of pyruvate?
cytosolic fermentation or entry into mitochondrion for aerobic respiration
Briefly describe cytosolic fermentation. Under what conditions does this occur?
In hypoxic conditions (like exercising muscle), cells w/out mitochondria (ex RBCs) or
anaerobic organisms, 2 pyruvate (from glycolysis) are reduced to 2 lactate in cytoplasm
to regenerate NAD+ for glycolysis
Which is more permeable: inner or outer mitochondrial membrane?
Outer is more permeable
Inner is not very permeable
How does pyruvate enter through inner mitochondrial membrane? What happens
right after?
MPC transports pyruvate from cytoplasm into mitochondria, where pyruvate
dehydrogenase is waiting for it
all enzymes used for pyruvate oxidation and citric acid cycle are found in _____.
This is an example of ______
, found in lumen of mitochondria
this is an example of compartmentation (enzyme regulation)
What can be said about a mitochondria's dynamic movement?
Cell adapts its mitochondria's morphology to its instantaneous needs
- they fuse, move, break apart depending on what the cell needs at the moment
What are examples of mammalian cells that don't have mitochondria? why?
Cells in lens of eye lack mitochondria (to prevent light from scattering)
RBCs (bc mitochondria would consume the O2 they transport)
What is general equation of pyruvate dehydrogenase working?
Pyruvate + NAD+ + CoA-SH --> Acetyl-CoA + NADH + CO2
What is structure of Pyruvate?
What is the structure of Acetyl-CoA? How is it made?
CO2 from pyruvate leaves and remaining molecule makes thioester bond (high in
energy)
What can be said about the CO2 that leaves in the decarboxylation of pyruvate
and conversion to Acetyl-CoA?
The C of CO2 is the first C from glucose that is taken off
The OVERALL rxn of pyruvate conversion to acetyl-CoA is _______, but
__________
energetically favorable (ΔG' = -33.5)
- very - value suggests highly regulated rxn
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
T or F: pyruvate is a key node in several catabolic and anabolic processes
T
What are the 2 fates of pyruvate?
cytosolic fermentation or entry into mitochondrion for aerobic respiration
Briefly describe cytosolic fermentation. Under what conditions does this occur?
In hypoxic conditions (like exercising muscle), cells w/out mitochondria (ex RBCs) or
anaerobic organisms, 2 pyruvate (from glycolysis) are reduced to 2 lactate in cytoplasm
to regenerate NAD+ for glycolysis
Which is more permeable: inner or outer mitochondrial membrane?
Outer is more permeable
Inner is not very permeable
How does pyruvate enter through inner mitochondrial membrane? What happens
right after?
MPC transports pyruvate from cytoplasm into mitochondria, where pyruvate
dehydrogenase is waiting for it
all enzymes used for pyruvate oxidation and citric acid cycle are found in _____.
This is an example of ______
, found in lumen of mitochondria
this is an example of compartmentation (enzyme regulation)
What can be said about a mitochondria's dynamic movement?
Cell adapts its mitochondria's morphology to its instantaneous needs
- they fuse, move, break apart depending on what the cell needs at the moment
What are examples of mammalian cells that don't have mitochondria? why?
Cells in lens of eye lack mitochondria (to prevent light from scattering)
RBCs (bc mitochondria would consume the O2 they transport)
What is general equation of pyruvate dehydrogenase working?
Pyruvate + NAD+ + CoA-SH --> Acetyl-CoA + NADH + CO2
What is structure of Pyruvate?
What is the structure of Acetyl-CoA? How is it made?
CO2 from pyruvate leaves and remaining molecule makes thioester bond (high in
energy)
What can be said about the CO2 that leaves in the decarboxylation of pyruvate
and conversion to Acetyl-CoA?
The C of CO2 is the first C from glucose that is taken off
The OVERALL rxn of pyruvate conversion to acetyl-CoA is _______, but
__________
energetically favorable (ΔG' = -33.5)
- very - value suggests highly regulated rxn
