The glycolytic pathway is located in the
mitochondrial matrix
mitochondrial inner membrane
mitochondrial intermembrane space
cytoplasm
nucleus
cytoplasm
What molecule is the end product of glycolysis?
Glyceraldehyde-3-phosphate
Phosphoenolpyruvate
Glucagon
Pyruvate
Acetyl-CoA
Pyruvate
______________ mediates the thermodynamically downhill movement of glucose across plasma membranes.
Insulin
Sucrase
Glucose transporters
Vesicles
Membrane pores
Glucose transporters
What is the purpose of phosphorylating glucose in the cytosol?
- To trap glucose in the cell
- To destabilize glucose and facilitate the next series of metabolic steps
- To convert it to a more soluble form
All of the above
A and B
A and B
Which two 3-carbon molecules are generated by the cleavage of fructose-1,6-bisphosphate?
- glyceraldehyde-3-phosphate and 3-phosphoglycerate
- glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
- pyruvate and phosphoenolpyruvate
enolase and 2-phosp
glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
What are the two metabolic intermediates of fructose that can feed into glycolysis?
Fructose-1,6, bisphosphate and dihydroxyacetone phosphate
Fructose-6 phophate and glyceraldehyde-3 phosphate
Glucose-6 phosphate and dihydroxyacetone phosphate
Fructose-6
Fructose-6 phosphate and dihydroxyacetone phosphate
What is the function of glyceraldehyde 3-phosphate dehydrogenase?
Oxidation by NAD+ and the formation of acyl phosphate
Oxidation of the alcohol to an aldehyde
Dehydration and dephosphorylation of GAP
Hydrolysis of GAP
None of the above
Oxidation by NAD+ and the formation of acyl phosphate
What are the primary metabolic fates of pyruvate?
Ethanol
Lactate
Acetyl-CoA
All of the above
None of the above
All of the above
What is substrate-level phosphorylation?
Phosphorylation of AMP by ATP
ATP synthesis when the phosphate donor is a substrate with high-phosphoryl-transfer potential
Phosphorylation of glycolytic intermediates
Phosphorylation of ATP coupled to an ion gradi
ATP synthesis when the phosphate donor is a substrate with high-phosphoryl-transfer potential
The substance ____________ must be regenerated for glycolysis to proceed.
NADH
NAD
FADH
FAD
All of the above
NAD
____________is an allosteric inhibitor of phosphofructokinase.
ATP
GTP
Acetyl-CoA
Glucose
NAD
ATP
The key regulatory enzyme for glycolysis is ______________.
hexokinase
aldolase
insulin
phosphofructokinase
glucokinase
phosphofructokinase
During exercise, glycolysis is stimulated by a:
high-energy charge of the cell.
feed-forward stimulation of pyruvate kinase.
negative feedback inhibition on hexokinase.
A and C
All of the above
feed-forward stimulation of pyruvate kinase.
phosphofructokinase reglatory stimulators/inhibtors?
Inhibit: ATP, feedback inhibition by Citrate
Stimulate: AMP, ADP
What cofactors are required for oxidation of the reduced dihydrolipoamide and resetting the enzyme?
FAD and NADH
FADH and NAD
FAD and NAD
FMN and NAD
FMN and FAD
FAD and NAD
Pyruvate dehydrogenase is _______________ when cellular energy levels are high.
activated
inhibited
phosphorylted
B and C
A and C
B and C
How many NADH molecules are produced by the PDH per glucose molecule?
0
1
2
3
4
2
____________: The product found by the condensation of oxaloacetate and acetyl CoA.
Citrate
Isocitrate
Aconitate
?-ketoglutarate
Malate
Citrate
The function of the citric acid cycle is to ____________ high-energy electrons.
channel
harvest
generate
oxidize
reduce
harvest
In which step of the citric acid cycle is FADH2 formed?
Isocitrate dehydrogenase
Succinyl CoA synthetase
Succinate dehydrogenase
Fumarase
None of the above
Succinate dehydrogenase
Succinate dehydrogenase is located in the ____________.
mitochondrial matrix
mitochondrial inner membrane
mitochondrial intermembrane space
cytoplasm
nucleus
mitochondrial inner membrane
In general, the citric acid cycle is inhibited under _____________ energy conditions.
low
neutral
high
intermediate
anaerobic
high
In the glyoxalate cycle, how many CO2 molecules are generated in one turn of the cycle?
0
1
2
3
4
0
________________ carries electrons from Complex III to Complex IV.
Q
Cytochrome c
NADH
FADH
Acetyl-CoA
Cytochrome c
Coenzyme Q is also called:
NADH
oxidoreductase
ubiquinone
all of the above
none of the above
ubiquinone
The Q cycle
- transfers electrons from a two-electron carrier to a one-electron carrier.
- recycles protons.
- acts as an NADH exchange with the cytosol.
A and B
A, B, and C
A and B,
transfers electrons from a two-electron carrier to a one-electron carrier.
recycles protons.
Electron flow down the electron-transport chain leads to:
the transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space.
the transport of protons across the inner mitochondrial membrane from the interme
the transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space.
ROS are harmful to cells because
- ROS are feedback inhibitors of the ET chain
- Formation of water necessary for cell metabolism Is prevented
- ROS damages DNA, proteins, and lipids
- Enzymes that reduce ROS make toxic molecules that damage DNA, proteins
ROS damages DNA, proteins, and lipids
What is the name given to the hypothesis proposed by Peter Mitchell to explain how ATP synthesis is coupled to electron transport.
Chemitonic Theory
Chemiosmolar Theory
Electron Transport Theory
Chemiosmotic Theory
Q Theory
Chemiosmotic Theory
What type of gradient is critical to ATP formation by oxidative phosphorylation?
Sodium ion
Chloride ion
Proton
Potassium ion
none of the above
Proton
The subunit of the ATPase embedded in the inner mitochondrial membrane is the:
anchor subunit
membrane-c ring subunit
F0 subunit
F1 subunit
Fm subunit
F0 subunit
ADP transport into the mitochondria is coupled to the export of :
Pi
Malate
H2O
ATP
OH-
ATP
When glucose is totally oxidized to CO2 and H2O, how many ATP molecules are made by oxidative phosphorylation out of a maximum yield of how many ATP molecules?
12 out of 30
26 out of 30
26 out of 32
12 out of 38
none of the above
26 out of 30
How are the glycolytic enzymes regulated?
- Through transcriptional control
- Through reversible phosphorylation
- Through allosteric control
- All of the above
- None of the above
All of the above
______________ are enzymes that catalyze the transfer of a phosphoryl group from ATP to an acceptor.
-Phosphatases
- Kinases
- ATPases
- Synthases
- Transferases
Kinases
____________ is the principle carbohydrate in living systems.
Sucrose
Glycogen
Lactose
Fructose
Glucose
Glucose
The product of aerobic glycolysis is ____________.
Lactate
Glyceraldehyde
Pyruvate
Formate
?-ketoglutarate
Pyruvate
The regeneration of ______________ in the reduction of pyruvate to lactate sustains glycolysis under anaerobic conditions.
NADH
NAD
FADH
FAD
FMN
NADH
The first irreversible enzymatic reaction unique to a metabolic pathway is called the ______________ step
regulated
high energy
exothermic
rate limiting
committed
committed
Which of the following functions as a "flexible swinging arm" when it transfers the reaction intermediate from one active site to the next?
FAD
NAD+
Lipoamide
Thiamine pyrophosphate
Coenzyme A
Lipoamide
Pyruvate dehydrogenase is _______________ when ATP-ADP ratios are high.
activated
inactivated
phosphorylated
B and C
A and C
inactivated
phosphorylated
B and C
The cellular carrier of activated acyl groups is ________________.
CoA
biotin
thiamine
folate
lipoamide
CoA
The citric acid cycle is also known as the:
Krebs cycle
tricarboxylic acid cycle
Cori cycle
A and B
A, B, and C
A and B
____________ is the citric acid cycle intermediate found at both the beginning and the end of the citric acid cycle.
Citrate
IsoCitrate
Malate
Succinate
Oxaloacetate
Oxaloacetate
How many molecules of CO2 are generated during one turn of the citric acid cycle?
0
1
2
3
4
2
Carbons generated by glycolysis, fatty acid oxidation, and degradation of some amino acids enter the citric acid cycle as:
Pyruvate
Acetyl-CoA
CO2
Succinate
?-ketoglutarate
Acetyl-CoA
In the citric acid cycle, __________ or ____________is produced by a substrate-level phosphorylation.
ATP or GTP
ATP or CTP
ATP or UTP
GTP or UTP
GTP or CTP
ATP or GTP
The ?-ketoglutarate dehydrogenase complex is functionally similar to
succinate dehydrogenase
pyruvate dehydrogenase
glyceraldehyde phosphate dehydrogenase
isocitrate dehydrogenase
malate dehydrogenase
pyruvate dehydrogenase
_______________ is where oxidative phosphorylation occurs in eukaryotes.
Cytoplasm
Outer mitochondrial membrane
Mitochondrial intermembrane space
Inner mitochondrial membrane
Mitochondrial matrix
Inner mitochondrial membrane
The citric acid cycle enzyme _______________ is also part of an electron-transport complex.
?-ketoglutarate dehydrogenase
succinate dehydrogenase
pyruvate dehydrogenase
isocitrate dehydrogenase
malate dehydrogenase
succinate dehydrogenase
________________ carries electrons from Complex III to Complex IV.
Coenzyme Q
NADH
FADH
Cytochrome c
CoA
Cytochrome c
Electron flow down the electron-transport chain leads to:
- the transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space.
- the transport of protons across the inner mitochondrial membrane from the int
the transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space.
Who first described the chemiosmotic hypothesis?
Peter Habler
Francis Mitchell
Edmund Hilary
James Watson
Peter Mitchell
Peter Mitchell
__________________ is a molecular assembly in the inner mitochondrial membrane that carries out the synthesis of ATP.
- F1F0 ATPase, or ATP synthase
- Pyruvate kinase
- Phosphoglycerate kinase
- Succinyl CoA synthetase
- none of the above
F1F0 ATPase, or ATP synthase
How does the rotation of the c ring lead to ATP synthesis?
- The c ring is linked tightly to the gamma and epsilon subunits in the stalk of F1.
- The c ring interacts with the beta subunit.
- The gamma subunit rotates with proton gradient formation, induc
All of the above
What is the energy source that drives the condensation of oxaloacetate and and acetyl CoA to produce citrate?
The thioester bond in acetyl CoA
What are the mechanisms that a cell uses to protect against the production of oxygen radicals?
Superoxide dismutase and catalase
Reduce oxygen free radicals to water and oxygen.
Other antioxidants such as vitamin C and E help
Describe how the Citric Acid Cycle is a central metabolic pathway in cells that is used for energy metabolism and functions as an anaplerotic pathway.
Synthesis of metabolic intermediates used by other pathways for synthesis of amino acids, nucleotides, fatty acids, glucose, and heme and chlorophylls.
Catabolic intermediates from amino acid degradation and beta oxidation of some fatty acids can feed int
How much ATP is generated by the three pathways: Glycolysis, CAC, ETC
30-32
Glycolysis: +2
CAC: +2
ETC: + ~ 26
Stages of Glycolysis
Regulatory molecules of glycolysis
Hexokinase,
Phosphofructosekinase*** (Committing step)
pyruvate kinase
What acts as a bridge between glycolysis and CAC.
Where is it located?
It is a commiting step for?
Outcome?
Pyruvate dehydrogenase complex,
Location: Matrix of mitochondria
Committing step for CAC
Produces: 2 NADH
CAC
The cycle some plants use that resembles the CAC cycle
Glyoxalate Cycle
-No Co2 generated
1 NAD, malate, oxalacetate, succinate
-can use to drive glucose synthesis
ATP Synthase
C ring pumps protons across space.
The __________ of glucose by ____________ reduces the intracellular composition of sugar, prevents transport out of the cell and feeds sugar into glycolysis.
phosphorylation, hexokinase
What are the three regualted enzymes in glycolysis?
hexokinose, phospfructokinase (commiting step), and pyruvate kinase
during glycolysis insulin binding translocates ____________ to cell membranes
glut-4
What is the final product of stage 1 of glycolysis?
DHAP (dihydroxyacetone phosphate) and GAP (glyceraldehyde 3-phosphate)
Production of ATP by high energy intermediates is called __________________.
Substrate level phosphorylation
In aerobic conditions pyruvate is converted to ______________ and enters the citric acid cycle.
In anaerobic conditions pyruvate is converted to ______________ or ___________
Acetyl CoA
Lactose or ethanol
How many ATP productin steps are there in the second stage of glycolysis?
2
Having a second phase in glycolysis is important for recycling _________ to NAD through _______________.
NADH
anaerobic fermentation
Phosphofructokinase and pyruvate kinase are inhibited by ______________
Hexokinase is inhibited by ______________
ATP
glucose 6-phosphate
How does metabolic regulation of glycolysis in the liver differ from muscle?
It relies on glucokinase and citrate to regulate phophofructokinase (PFK) rather than hexokinase. Doesn't need as quick of a response.
What 3 factors can turn off glycolysis?
High:
ATP
NADH
Citrate
High levels of ATP in the cell causes inactivation of PDH by activating _____________.
PDH kinase
______________ is the commiting step to the citric acid cycle (fatty acid synthesis) from glycolysis.
PDH
In a high energy situation, ____________ ___________ & __________ activate PDH kinase, inhibiting the PDH.
ATP
Acetyl CoA
NADH
In a low energy situation ___________ & _____________ inhibit PDH kinase phosphorylation, activating the PDH cycle.
ADP
Pyruvate
What are the three stages of phase 1 of the CAC and their possible products?
Citrate synthase - citrate used in glycolysis
Isocitrate dehydrogenase - first CO2 + NADH
a-ketogluterate dehydrogenase complex - second CO2 + NADH
Which section of CAC produces ATP?
Succinyl CoA synthetase (substrate level phosphorylation)
Which section of the CAC produces FADH used in the ETC?
Succinate dehydrogenase - (succinate to fumerate)
Which redox step in the CAC regenerates oxaloacetate? What else does it produce?
malate dehydrogenase
(malate to oxaloacetate)
- produces NADH
What is the cycle similar to the CAC in plants and microorganisms?
glyoxalate - No CO2 generated, 2 acetyl CoA used, makes 2 NADH
The ________________ cycle is functionally similar to the PDH complex but uses ________________ as substrate.
a- ketogluterate dehydrogenase
a-ketogluterate
What is produced for every 1 molecule of glucose in the CAC
4 CO2
2 ATP
6 NADH
2 FADH
(ETC) The energy of electrons flowing down the redox gradients in complexes I,III & IV is used to pump ____________ out of the mitochondria into ___________.
Protons
Intramembrane space
How many protons are pumped in the ETC per electron pair (NADH or FADH
6
In the ETC electrons will flow from more ____________ to ______________ reduction potentials.
Negative to positive
What molecules are used to help electrons flow through the complexes of the ETC? Where is it used?
Ubiquinone (Q) and Ubiquinol
- Used between complex II and III
The ________ is a membrane embedded protein complex used in ATP synthasis.
F1F0 ATP Synthase
The _________ complex is embedded in the inner mitochondrial membrane and transports H+
F0 complex
Conformational changes of the alpha and beta proteins in the ____________ drive ATP synthesis in the mitochondrial matrix
F1 complex