Redox and Glycolysis Quiz
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Name:
Knowledge. Answer the following questions on foolscap where applicable.
1.a) Consider the following statement: “anaerobic respiration requires the absence of oxygen.” Do you agree with
this statement and justify your answer.
b) Consider the type of respiration you would classify cellular respiration. Does this classification apply to all the
stages of cellular respiration? Explain.
2. Some textbooks write the chemical reaction of cellular respiration as:
C6H12O6(aq) + 6 H2O(l) + 6 O2(g) ö 6 CO2(g) + 12 H2O(l) + 6 O2(g) + Energy
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a) What type of process is this (label two ways).
b) What is unique about this form of the chemical equation? Explain what you think it means.
3. Consider the following chemical reaction: 2 MnF3 + 3 PbCl4 ö 3 PbF2 + 2 MnCl6
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a) Identify the specific chemical undergoing oxidation and the specific chemical undergoing reduction.
b) Identify the specific oxidizing agent and the specific reducing agent.
c) Explain how two metals react in a redox reaction including changes in energy.
d) If this was an organic reaction, what element routinely changes in number to show that a redox reaction occurred?
How does it change to demonstrate reduction?
e) What chemical undergoes oxidation and what chemical is the oxidizing agent in cellular respiration?
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4.a) What type of molecule is nicotinamide adenine dinucleotide?
b) Identify 2 reasons NAD+ is used an electron carrier.
c) Why do you think the redox of NAD+ begins with a chemical redox?
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5.a) Explain how reaction coupling works to ensure the formation of desirable products.
b) Explain 2 reasons the desirable reaction in a coupled reaction does not simply revert.
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6.a) Where does glycolysis take place in most eukaryotic cells?
b) Identify the advantage and disadvantage of glycolysis taking place at that location.
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7.a) Why is glucose immediately
phosphoylated upon transport into
the cell?
b) Consider the adjacent portion of
glycolysis. Why is glucose 6-phosphate
converted to fructose 6-phosphate?
c) If, upon formation, dihydroxyacetone
phosphate is immediately converted
into glyceraldehyde 3-phosphate,
why doesn’t glycolysis just produce two G3Ps in the first place?
d) Consider the adjacent portion of glycolysis. It might seem silly that phosphate
was added, then immediately removed to form ATP. Explain why this reaction works.
e) During the following conversion, water is removed from 2-phosphoglycerate (as
seen below). Explain the benefit of the water for the 2-phosphoglycerate prior to
its removal (aside from bond completion).
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Redox and Glycolysis Quiz
/41
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Knowledge. Answer the following questions on foolscap where applicable.
1.a) Consider the following statement: “anaerobic respiration requires the absence of oxygen.” Do you agree with
this statement and justify your answer.
!
!
!
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Name:
this statement is wrong
anaerobic respiration just does not use oxygen in order to proceed
but it can (for most organisms) proceed regardless of oxygen levels
b) Consider the type of respiration you would classify cellular respiration. Does this classification apply to all the
stages of cellular respiration? Explain.
!
!
no
glycolysis is anaerobic
2. Some textbooks write the chemical reaction of cellular respiration as:
C6H12O6(aq) + 6 H2O(l) + 6 O2(g) ö 6 CO2(g) + 12 H2O(l) + 6 O2(g) + Energy
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a) What type of process is this (label two ways).
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redox
exergonic
b) What is unique about this form of the chemical equation? Explain what you think it means.
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water is on both sides
the water used and produced must represent significantly different chemicals
3. Consider the following chemical reaction: 2 MnF3 + 3 PbCl4 ö 3 PbF2 + 2 MnCl6
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a) Identify the specific chemical undergoing oxidation and the specific chemical undergoing reduction.
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!
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b) Identify the specific oxidizing agent and the specific reducing agent.
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the metal with the stronger attraction for electrons steals electrons from the other metal
as a result the electrons now have less potential energy since they are more strongly held by the
nucleus
d) If this was an organic reaction, what element routinely changes in number to show that a redox reaction occurred?
How does it change to demonstrate reduction?
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oxidizing agent = Pb4+
reducing agent = Mn3+
c) Explain how two metals react in a redox reaction including changes in energy.
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oxidation = Mn3+
reduction = Pb4+
hydrogen atoms
increases in number
e) What chemical undergoes oxidation and what chemical is the oxidizing agent in cellular respiration?
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oxidation = glucose
oxidizing agent = oxygen
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4.a) What type of molecule is nicotinamide adenine dinucleotide?
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b) Identify 2 reasons NAD+ is used an electron carrier.
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the energized glucose 6-phosphate is now trapped in the cell
b) Consider the adjacent portion of glycolysis. Why is glucose 6-phosphate converted to fructose 6-phosphate?
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under anaerobic conditions, some energy is quickly and continually harvested for immediate use by
the cell to ensure its survival (at least for a while)
the NADH formed cannot be converted directly into ATP until is somehow crosses into the
mitochondria and in doing so, some of its energy is lost
7.a) Why is glucose immediately phosphoylated upon transport into the cell?
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cytosol
b) Identify the advantage and disadvantage of glycolysis taking place at that location.
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if this reaction is endergonic, the activation energy of the reverse reaction is higher and so the
reverse reaction is less spontaneous
often in biochemical pathways, the products of one reaction are immediately picked up by a nearby
enzyme to initiate the next reaction (like joined train cars all pull together once one begins moving)
6.a) Where does glycolysis take place in most eukaryotic cells?
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some of the energy from an exergonic reaction
is used as activation energy for a desirable reaction (which may or may not be exergonic or
endergonic, but the activation energy must be less than the released energy from the coupled
reaction–to allow for wasted energy due conversion)
b) Explain 2 reasons the desirable reaction in a coupled reaction does not simply revert.
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accepting a hydrogen atom with its electron, increases the attraction for electrons
so it can steal another electron from an organic molecule
5.a) Explain how reaction coupling works to ensure the formation of desirable products.
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the conversion from NAD+ ö NADH+ requires very little energy
which means the most potential energy possible is captured
also could say it is one of the most versatile molecules in our bodies (but this is not a good answer)
c) Why do you think the redox of NAD+ begins with a chemical redox?
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coenzyme
it weakens a bond to allow the addition of another phosphate
which creates a molecule, fructose 1,6-diphosphate which can be more easily split in two
c) If, upon formation, dihydroxyacetone phosphate is immediately converted into glyceraldehyde 3-phosphate, why
doesn’t glycolysis just produce 2 G3Ps in the first place?
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fructose 1,6-diphosphate is not symmetrical so when it splits, the product is 2 different molecules
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d) Consider the adjacent of portion glycolysis. It might seem silly that phosphate
was added, then immediately removed to form ATP. Explain why this reaction works.
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the phosphate added was inorganic phosphate free in the cytosol so this did not require any energy
but all the electronegative oxygen atoms present destablized the the 1,3 bisphosphoglycerate enough
to allow ATP to form
e) During the following conversion, water is removed from 2-phosphoglycerate (as seen below). Explain the
benefit of the water for the 2-phosphoglycerate prior to its removal (aside from bond completion).
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the OH from the water on the bottom carbon allows hydrogen bonding to take place with the O in
the phosphate
to stabilize the molecule so it can contain the phosphate
Prepared by K. Zuber