BB 451 Exam 1 questions with verified
answers graded A+
Where does the citric acid cycle take place in eukaryotes? In prokaryotes? (Be
specific) - correct answer ✔✔-mitochondrial matrix for eukaryotes
-cytosol for prokaryotes
Oxygen is not directly used in the CAC but it's important. Why? - correct answer
✔✔Oxygen is indirectly required to regenerate electron carriers
The citric acid cycle can only begin if ___________ is present. This molecule can
be obtained from pyruvate, beta oxidation of fatty acids, ketone bodies, and
amino acid metabolism. - correct answer ✔✔acetyl-CoA
What are the electron carriers of the CAC? During the CAC, what is produced and
released in total? - correct answer ✔✔Electron carriers: NAD+ and FAD
Before the CAC starts, 1 NADH and 1 CO2 are made.
Produced: 3 NADH, 1 FADH2, 1 GTP.
Starting from acetyl CoA, how many ATP are made per citric acid cycle? What if
you count the pyruvate dehydrogenase step? - correct answer ✔✔Starting from
acetyl-CoA, you'll generate 9 ATP. Starting from pyruvate, you'll generate 11.5 ATP.
Including the GTP, you'd make 12.5 ATP if you started from pyruvate.
,Starting with glucose, how many ATP are made? - correct answer ✔✔30 ATP
What makes coenzyme A a high energy carrier? Why is this important? (Second
question found on lecture 1, slide 21) - correct answer ✔✔High energy carrier
because of its thioester bonds
Cleavage of thioester bond provides large negative free energy change
This is important because acetyl is bound to CoA via a thioester linkage allowing
for efficient transfer to other carbons
Important bc it provides energy for endergonic reactions.
What is the function of pyruvate dehydrogenase? Why is it so important for the
CAC? - correct answer ✔✔The main function of pyruvate dehydrogenase is to turn
pyruvate into acetyl-CoA. The reason this is important is because the CAC cannot
start without acetyl-CoA.
-catalyzes decarboxylation of pyruvate, transfer of the acetyl group to CoA , and
the capture of two electrons as NADH + H+
What are the prosthetic groups and substrates of the PDH complex? - correct
answer ✔✔Prosthetic groups: thiamine pyrophosphate (TPP), lipoamide, FAD
Substrates: pyruvate, CoA, NAD+
, What does PDH do? How is the thioester bond achieved and what is used in
oxidative phosphorylation? What happens to all of the catalytic groups of PDH?
(All on PDH overview slide) - correct answer ✔✔PDH converts pyruvate (3
carbons) into an acetyl group (2 carbons)
The high energy thioester bond is achieved by coupling to an oxidation event
which creates 1 NADH + H+ used in oxidation phosphorylation.
All catalytic groups are returned to their original state for catalysis of the next
reaction.
Name the 8 intermediates of the CAC in order. Name an mnemonic to go with it if
you want. - correct answer ✔✔Oxaloacetate - Citrate - Isocitrate - alpha
Ketoglutarate - Succinyl-CoA - Succinate - Fumerate - Malate
Mnemonic:
Our City Is Kept Safe And Sound From Malice
Describe the 8 steps of the citric acid cycle.
Hint: don't focus on the organic chemistry material. Victor said that's not
necessary to memorize for the test. Don't write the mechanism, just write what's
going on. For every step that's necessary, list of NADH, FADH2 or GTP is formed.
Then right the net reaction at the end. - correct answer ✔✔Step 1: OAA and
acetyl-CoA react to for, Cytril CoA, which then reacts with water to form citrate.
The purpose of this step is to create a molecule that will
undergo decarboxylation.
answers graded A+
Where does the citric acid cycle take place in eukaryotes? In prokaryotes? (Be
specific) - correct answer ✔✔-mitochondrial matrix for eukaryotes
-cytosol for prokaryotes
Oxygen is not directly used in the CAC but it's important. Why? - correct answer
✔✔Oxygen is indirectly required to regenerate electron carriers
The citric acid cycle can only begin if ___________ is present. This molecule can
be obtained from pyruvate, beta oxidation of fatty acids, ketone bodies, and
amino acid metabolism. - correct answer ✔✔acetyl-CoA
What are the electron carriers of the CAC? During the CAC, what is produced and
released in total? - correct answer ✔✔Electron carriers: NAD+ and FAD
Before the CAC starts, 1 NADH and 1 CO2 are made.
Produced: 3 NADH, 1 FADH2, 1 GTP.
Starting from acetyl CoA, how many ATP are made per citric acid cycle? What if
you count the pyruvate dehydrogenase step? - correct answer ✔✔Starting from
acetyl-CoA, you'll generate 9 ATP. Starting from pyruvate, you'll generate 11.5 ATP.
Including the GTP, you'd make 12.5 ATP if you started from pyruvate.
,Starting with glucose, how many ATP are made? - correct answer ✔✔30 ATP
What makes coenzyme A a high energy carrier? Why is this important? (Second
question found on lecture 1, slide 21) - correct answer ✔✔High energy carrier
because of its thioester bonds
Cleavage of thioester bond provides large negative free energy change
This is important because acetyl is bound to CoA via a thioester linkage allowing
for efficient transfer to other carbons
Important bc it provides energy for endergonic reactions.
What is the function of pyruvate dehydrogenase? Why is it so important for the
CAC? - correct answer ✔✔The main function of pyruvate dehydrogenase is to turn
pyruvate into acetyl-CoA. The reason this is important is because the CAC cannot
start without acetyl-CoA.
-catalyzes decarboxylation of pyruvate, transfer of the acetyl group to CoA , and
the capture of two electrons as NADH + H+
What are the prosthetic groups and substrates of the PDH complex? - correct
answer ✔✔Prosthetic groups: thiamine pyrophosphate (TPP), lipoamide, FAD
Substrates: pyruvate, CoA, NAD+
, What does PDH do? How is the thioester bond achieved and what is used in
oxidative phosphorylation? What happens to all of the catalytic groups of PDH?
(All on PDH overview slide) - correct answer ✔✔PDH converts pyruvate (3
carbons) into an acetyl group (2 carbons)
The high energy thioester bond is achieved by coupling to an oxidation event
which creates 1 NADH + H+ used in oxidation phosphorylation.
All catalytic groups are returned to their original state for catalysis of the next
reaction.
Name the 8 intermediates of the CAC in order. Name an mnemonic to go with it if
you want. - correct answer ✔✔Oxaloacetate - Citrate - Isocitrate - alpha
Ketoglutarate - Succinyl-CoA - Succinate - Fumerate - Malate
Mnemonic:
Our City Is Kept Safe And Sound From Malice
Describe the 8 steps of the citric acid cycle.
Hint: don't focus on the organic chemistry material. Victor said that's not
necessary to memorize for the test. Don't write the mechanism, just write what's
going on. For every step that's necessary, list of NADH, FADH2 or GTP is formed.
Then right the net reaction at the end. - correct answer ✔✔Step 1: OAA and
acetyl-CoA react to for, Cytril CoA, which then reacts with water to form citrate.
The purpose of this step is to create a molecule that will
undergo decarboxylation.
