chapter 19 Flashcards
Reactions catalyzed by which of the following proteins do NOT contribute electron carriers to the electron transport chain?
Succinate dehydrogenase
Glucose-6-phosphate dehydrogenase
Alcohol dehydrogenase
Malate dehydrogenase
Glucose-6-phosphate dehydrogenase- this is one of first steps in PPP it generates NADPH not NADH so is not used to donate electrons
-Succinate dehydrogenase is part of Complex II of the electron transport chain. It oxidizes succinate to fumarate and transfers electrons to ubiquinone, which becomes reduced to ubiquinol (QH2).
- Alcohol Dehydrogenase converts ethanol to acetaldehyde, and this reaction generates NADH which can enter ETC at complex 1
- Malate dehydrogenase (malate aspartate shuttle) catalyzes the conversion of malate to oxaloacetate, and this reaction produces NADH.
The NADH generated by malate dehydrogenase can also contribute electrons to Complex I of the electron transport chain.
Which enzyme passes electrons directly or indirectly to coenzyme Q without pumping protons?
Succinate dehydrogenase
Glycerol-3-phosphate dehydrogenase
Acyl-CoA dehydrogenase
All options are correct
All options are correct- see part on cheatsheet about other entry points to ETC
In the mitochondria a motive force for ATP/ADP exchange is the __________ and for importing inorganic phosphate into the matrix is the ___________.
proton gradient, membrane potential (negative in the matrix)
membrane potential (negative in the matrix), proton gradient
membrane potential (positive in the matrix), sodium ion gradient
membrane potential (positive in the matrix), proton gradient
membrane potential (negative in the matrix), sodium ion gradient
membrane potential (negative in the matrix), proton gradient
Which of the following is true regarding Ubiquinone?
It contains one FAD and one iron-sulfur center
It must accept two protons and 4 electrons to go from a fully reduced to a fully oxidized state.
It is assigned to neither Complex II nor Complex III since its role is to function as a carrier between them
It can accept one electron to become a relatively stable radical
None of the above statements is true regarding Ubiquinone
It can accept one electron to become a relatively stable radical
Fully reduced Electron Transferring Flavoprotein passes its electrons to Coenzyme Q. In what metabolic pathway was ETF reduced by an adenine nucleotide electron carrier?
Kreb’s Cycle
Pentose Phosphate Pathway
Beta-oxidation of fatty acids
Glycolysis
Glyoxylate Pathway
Beta-oxidation of fatty acids
the side chain reaction that uses ETF to go into respiratory chain (ETC)
The following molecules are produced by the first phase of the Q cycle:
Ubiquinol (fully reduced)
Semiquinone radical
Ubiquinone (fully oxidized)
Semiquinone radical
Ubiquinone (fully oxidized)
A new electron carrier has been discovered. It directly passes 4 electrons to ubiqinol. How many ATPs is this carrier worth when fully charged?
3 atp
I add an inhibitor of mitochondrial respiration that prevents electron transfer to cytochrome c. Which of the following outcomes is the most likely?
Normal levels of QH2 and NADH; increased oxygen consumption
Buildup of QH2 but not NADH; decreased oxygen consumption
Buildup of both QH2 and NADH; decreased oxygen consumption
Buildup of QH2 but not NADH, increased oxygen consumption
Normal levels of QH2 and NADH; decreased oxygen consumption
Buildup of both QH2 and NADH; decreased oxygen consumption
How many protons must be pumped across the membrane in order to make 1 molecule of ATP? (Consider all processes. Assume, as we did in class, that the c-ring of Fo has 9 subunits).
2.5
3
6
10
4
4
Which of the following dehydrogenation reactions do NOT contribute NADH to Complex I?
a-ketoglutarate dehydrogenase
glutamate dehydrogenase
Malate dehydrogenase
acyl-CoA dehydrogenase
Isocitrate dehydrogenase
acyl-CoA dehydrogenase
a-ketoglutarate dehydrogenase is involved in the citric acid cycle (Krebs cycle) and converts α-ketoglutarate to succinyl-CoA, producing NADH in the process.
glutamate dehydrogenase converts glutamate to α-ketoglutarate and produces NADH in the process.
Malate dehydrogenase: malate aspartate shuttle
Isocitrate dehydrogenase catalyzes the conversion of isocitrate to α-ketoglutarate in the citric acid cycle, producing NADH in the process.
Cytochrome c is a mobile electron carrier that moves among Complexes of the mitochondrial electron transport chain. Which Complexes does it move between?
3 and 4
In ATP synthase, the interaction of stalk with a beta-subunit in the F1 complex contributes to ATP synthesis by:
Decreasing the free energy of ATP dissociation from the beta subunit
On which side of the chloroplast membrane is the ATP Synthase active site?
On the lumenal side of the stromal membranes
On the cytoplasmic side
On the Inside of the outer membrane
On the outside of the outer membrane
On the stromal side of the membranes
On the stromal side of the membranes
When the [NADPH]/[NADP+] ratio in plants is low, photophosphorylation is primarily non-cyclic. What is/are the major product(s) of photophosphorylation in this circumstance?
I. ATP
II. NADPH
III. O2
II and III
The initial reaction in the REDUCTIVE phase (Stage 2) of the Calvin cycle is the reverse of a particular reaction in another pathway. What is the driving force for this reaction in the Calvin cycle?
This reaction uses Mg2+ and the elevated concentration of Mg2+ during the day helps to drive it forward
In the direction it runs in the Calvin cycle, there is a large and negative LaTeX: \DeltaΔ
G’0 so the reaction is naturally favorable.
This reaction is favorable due to the high concentration of NADPH made in the light reactions of photosynthesis.
This reaction is favorable due to the high concentration of ATP made in the light reactions of photosynthesis.
This reaction is favorable due to the high concentration of ATP made in the light reactions of photosynthesis.
