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WorksheetsBiochem: Citric Acid Cycle
Total questions: 62
Worksheet time: 34mins
Only a small amount of energy is captured in glycolysis.
True
False
Glycolysis can occur in both aerobic and anaerobic environment.
True
False
Which has a higher delta G?
full oxidation
glycolysis
Glycolysis is NOT thermodynamically favorable.
True
False
Oxygen is required for glycolysis.
True
False
Oxygen is required for citric acid cycle.
True
False
Which organell is the major site for aerobic energy production in eukaryotic cells?
Ribosome
Nucleus
smooth ER
mitochondria
Where are mitochondria most abundant? (two answers)
liver cells
pancreatic cells
kidney cells
muscle cells
How do RBC's get their energy?
glycolysis
Citric acid cycle
both glycolysis and citric acid cycle
Red blood cells have many mitochondria.
True
False
Where are the enzymes for the citric acid cycle located?
inner mitochondrial membrane
matrix
outer mitochondrial membrane
Which is MORE selective?
inner mitochondrial membrane
outer mitochondrial membrane
What serves as a link to the electron transport chain and oxidative phosphorylation?
citric acid cycle
glycolysis
gluconeogenesis
glycogenolysis
The citric acid cycle generates coenzymes.
True
False
What are two important enzymes generated by the TCA cycle?
NADH
NADPH
FADH2
What is the role of NADH and FADH2?
to generate lactic acid
to pass their electrons to oxygen to generate energy for the cell
to gain electrons from the TCA cycle
The more negative the electron potential, the more readily they give up electrons.
True
False
Which is a better electron DONOR?
NADH
FADH2
What can feed into the TCA cycle as starting material?
NADH
fatty acids
amino acids
glucose
What is the starting material for the TCA?
phosphate
Acetyl CoA
NADH
ATP
What is the product of TCA cycle?
1 ATP
2 CO2
lactic acid
NADH and FADH2
Where do NADH and FADH2 go after they are formed in the TCA cycle?
into the matrix
ATP synthase
ETC
Where does the electron transport chain take place?
in the inner mitochondrial membrane
in the outer mitochondrial membrane
in the matrix
Which kind of amino acids can be turned into Acetyl-CoA and feed into the TCA cycle?
ketogenic amino acids
glucogenic amino acids
Where can gllucogenic AA be used?
to make Acetyl CoA
in gluconeogenesis
in the TCA cycle
The citric acid cycle ONLY occurs in the mitochondrial matrix.
True
False
Where does glycolysis occur?
cytoplasm
mitochondria
in the nucleus
Where is succinate dehydrogenase located?
the mitochondrial matrix
the inner membrane of the mitochondria
the outer membrane of the mitochondria
Where does pyruvate come from?
glycolysis in the cytoplasm
the matrix
the nucleus
Pyruvate cannot cross the inner mitochondrial membrane.
True
False
Where does oxidative phosphorylation occur?
in the cytoplasm
in the matrix
in the inner membrane
Where does the ETC occur?
cytoplasm
inner membrane
outer membrane
matrix
What must happen to pyruvate before entering the citric acid cycle?
it must be converted to Acetyl CoA
it must be phosphorylated
it must be degredated
nothing, it enters the TCA directly
How does pyruvate enter the mitochondrial matrix?
gets converted to malate
through a transporter
passive diffusion
The decarboxylation of pyruvate to make acetyl CoA is irreversible.
True
False
What does the dehydrogenase complex do and how many enzymes make this up?
removes carboxy group and adds S-CoA; 3
adds phosphate group;2
removes hydrogen; 5
How many coenzymes are required for the pyruvate dehydrogenase complex?
1
2
5
3
TPP,lipoyllysine, and FAD are all....
prosthetic groups
coenzymes
cofactors
ions
NAD+ and CoA-SH are co-substrates.
True
False
What are the products of the pyruvate dehydrogenase complex?
CO2
FADH2
Acetyl-CoA
NADH
How many NADH's are made outside of the TCA cycle?
1NADH
2 NADH
3 NADH
Where is the NADH made outside of the citric acid cycle?
in the conversion of citrate to isocitrate
in the conversion of fumarate to malate
in the conversion of pyruvate to Acetyl-CoA
Acetyl-CoA is a low energy molecule.
True
False
What is the order of the reactions in the conversion of pyruvate to Acetyl CoA?
Decarboxylation
(releases CO2)
Oxidation
(releases 2 electrons)
Transfer to CoA
Pyruvate dehydrogenase complex is only made up of one enzyme.
True
False
Pyruvate dehydrogenase is
enzyme 1
enzyme 2
enzyme 3
dihydrolipoyl transacetylase is
enzyme 1
enzyme 2
enzyme 3
dihydrolipoyl dehydrogenaase is
enzyme 1
enzyme 2
enzyme 3
The short distance between catalytic sites is an advantage of a multienzyme complex.
True
False
Why is it important for the enzyme complex to have short distances between catalytic sites?
to work slower
to minimize side reactions
the maximize side reactions
Which reaction has a C-C bond formation?
Condensation of acetyl-CoA and oxaloacetate
Isomerization by dehydration
oxidative decarboxylations
Condensation of acetyl-CoA and oxaloacetate (1st step of CAC) is the only reaction with C-C bond formation.
True
False
Step 1 of CAC where acetyl Co-A and oxaloacetate go through condensation reaction is
Favorable
unfavorable
reversible
irreversible
What must be present for the first step of CAC?
oxygen
oxaloacetate
citrate
ATP
Step 2 of CAC is the dehydration and rehydration of citrate.
True
False
What enzyme catalyzes the dehydration and rehydration of citrate?
aconitase
citrate synthase
isocitrate dehydrogenase
Citrate is a poor substrate for oxidation but gets turned into isocitrate that is a good substance for oxidation.
True
False
They dehydration and rehydration of citrate is
reversible
unfavorable
favorable
irreversible
What allows the dehydration and rehydration of citrate to pull forward even though it is thermodynamically unfavorable?
substrate concentration is kept low
product concentration is kept high
product concentration is kept low
Step 3 of CAC What is the intermediate between isocitrate and a-ketoglutarate?
oxalosuccinate
not this one
The first NADH produced within the CAC is the oxidative decarboxylation of isocitrate.
True
False
The formation of a-ketoglutarate from isocitrate is
favorable
irreversible
unfavorable
reversible
