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Chem 153A Verified Exam latest update Midterm 1&2
and Final 2025/2026
Why is the Electron Transport Chain (ETC) located in the
cristae of the mitochondria? - Answers-Part of cellular
respiration to create ATP. The cristae increases the
surface area of the inner membrane which allows faster
production of ATP since there's more places to do the
process
What is the functional significance of the folds in the inner
mitochondrial membrane for the ETC? - Answers-The
inner folds create the inter-membrane space that is
between them. The folds let more ETC enzymes and ATP
synthase to be packed into the mitochondrion.
What species gives up electrons in redox reactions and
potentials? - Answers-The species that is the getting
oxidized.
What species takes on electrons in redox reactions and
potentials? - Answers-The species that is getting reduced.
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How do you determine redox potential by combining half-
reactions? - Answers-1: Divide the equation into half-
reactions
2: Balance each half-reaction for mass and charge
3: Equalize the # of electrons transferred
4:Add the half-reactions together
If Tin (II) chloride solution is mixed with an acidic
potassium permanganate solution, predict the redox
reaction. - Answers-Tin (II) chloride solution = Sn2+, H2O,
and Cl-
Acidic potassium permanganate = K+, H2O, MnO4-
- Add it all into the same beaker
-Find what the strongest oxidizing and reducing agents
- Add the 2 half reactions together to find the product
How do you convert redox potential into free energy
change? - Answers-Delta G = -RT ln K
The Electron Transport Chain (ETC) full redox reaction
catalyzed: reducing/oxidizing species - Answers-
Substrate: H2 (reduced) goes to the substrate (oxidized)
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The acceptor: NAD + or FAD goes to H2 (NADH or
FADH2)
Reduced e- carrier goes through oxidized e- carrier and
thru and thru then to 2H + 1/2 O2 goes to H2O
How many protons are pumped by complex 1 in the ETC?
- Answers-Pumps 4 protons
How many protons are pumped by complex 2 in the ETC?
- Answers-Does not pump protons directly, does send out
2 protons to the next complex in the form of reduced
ubiquinol
Ubiquinol - Answers-Also known as coenzyme Q, is a lipid
with a quinone ring structure at the top
- can be reduced with 2 electrons, then travels to complex
III next
How many protons are pumped by complex 3 in the ETC?
- Answers-Transfers 4 protons across the membrane per
pair of electrons
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How many protons are pumped by complex 4 in the ETC?
- Answers-4 protons: 2 protons per pair of electrons
ETC Complex I - Answers-NADH - Q (ubiquinol)
oxidorecductase
electrons from NADH
Mechanical/Conformational change
Oxidoreductase - Answers-- large, multi-subunit protein
complex
- Accepts e- from NADH and passes them to FMN ( flavin
mononucleotide like FAD)
- passes e- thru Fe/S clusters to ubiquinone 1 at a time
- uses this electrical work to pump 4 H+ ions out of the
matrix into the intermembrane space
Complex I net reaction: - Answers-NADH + 5H+ N + Q ->
NAD+ + QH2 + 4H+ P
Protons are transferred thru proton "wires" - series of AA
that undergo protonation and deprotonation
Chem 153A Verified Exam latest update Midterm 1&2
and Final 2025/2026
Why is the Electron Transport Chain (ETC) located in the
cristae of the mitochondria? - Answers-Part of cellular
respiration to create ATP. The cristae increases the
surface area of the inner membrane which allows faster
production of ATP since there's more places to do the
process
What is the functional significance of the folds in the inner
mitochondrial membrane for the ETC? - Answers-The
inner folds create the inter-membrane space that is
between them. The folds let more ETC enzymes and ATP
synthase to be packed into the mitochondrion.
What species gives up electrons in redox reactions and
potentials? - Answers-The species that is the getting
oxidized.
What species takes on electrons in redox reactions and
potentials? - Answers-The species that is getting reduced.
,2|Page
How do you determine redox potential by combining half-
reactions? - Answers-1: Divide the equation into half-
reactions
2: Balance each half-reaction for mass and charge
3: Equalize the # of electrons transferred
4:Add the half-reactions together
If Tin (II) chloride solution is mixed with an acidic
potassium permanganate solution, predict the redox
reaction. - Answers-Tin (II) chloride solution = Sn2+, H2O,
and Cl-
Acidic potassium permanganate = K+, H2O, MnO4-
- Add it all into the same beaker
-Find what the strongest oxidizing and reducing agents
- Add the 2 half reactions together to find the product
How do you convert redox potential into free energy
change? - Answers-Delta G = -RT ln K
The Electron Transport Chain (ETC) full redox reaction
catalyzed: reducing/oxidizing species - Answers-
Substrate: H2 (reduced) goes to the substrate (oxidized)
,3|Page
The acceptor: NAD + or FAD goes to H2 (NADH or
FADH2)
Reduced e- carrier goes through oxidized e- carrier and
thru and thru then to 2H + 1/2 O2 goes to H2O
How many protons are pumped by complex 1 in the ETC?
- Answers-Pumps 4 protons
How many protons are pumped by complex 2 in the ETC?
- Answers-Does not pump protons directly, does send out
2 protons to the next complex in the form of reduced
ubiquinol
Ubiquinol - Answers-Also known as coenzyme Q, is a lipid
with a quinone ring structure at the top
- can be reduced with 2 electrons, then travels to complex
III next
How many protons are pumped by complex 3 in the ETC?
- Answers-Transfers 4 protons across the membrane per
pair of electrons
, 4|Page
How many protons are pumped by complex 4 in the ETC?
- Answers-4 protons: 2 protons per pair of electrons
ETC Complex I - Answers-NADH - Q (ubiquinol)
oxidorecductase
electrons from NADH
Mechanical/Conformational change
Oxidoreductase - Answers-- large, multi-subunit protein
complex
- Accepts e- from NADH and passes them to FMN ( flavin
mononucleotide like FAD)
- passes e- thru Fe/S clusters to ubiquinone 1 at a time
- uses this electrical work to pump 4 H+ ions out of the
matrix into the intermembrane space
Complex I net reaction: - Answers-NADH + 5H+ N + Q ->
NAD+ + QH2 + 4H+ P
Protons are transferred thru proton "wires" - series of AA
that undergo protonation and deprotonation
