unit 3 exam Flashcards
what compounds are consumed and produced in glycolysis
2 ATP consumed, 4 ATP produced, 2 NADH produced
What are the payoff steps of glycolysis?
oxidizing glyceraldehyde (energy stored in phosphate bond and NADH)
energy from phosphoenolpyruvate (PEP)
How many kinases are involved in glycolysis?
3
How is phosphofructokinase regulated and what does it do?
when there are high levels of ATP, fatty acids inhibit the enzyme
when there are high levels of AMP, ADP stimulates the enzyme
catalyzes phosphorylation
If an enzyme pathway is blocked, which compound will accumulate?
the compound before the largest positive change in free energy
What are the 2 pathways of fermentation?
glucose–>pyruvate–>lactate
glucose–>pyruvate–>aldehyde–>ethanol
In anaerobic conditions:
Which step generates NADH?
Which step generates NAD+?
NADH generated going from glucose to pyruvate because consumes NAD+ to drive reaction
NAD+ generated going from aldehyde to the ethanol
What drives the citric acid cycle?
reduction of NAD+
How many steps of the citric acid cycle form CO2?
2
How many steps of the citric acid cycle involve oxidation?
4
What regulates citrate synthase?
ATP and NADH
What do dehydrogenases do?
catalyze oxidation
What are the signs of a thiamine deficiency?
decreased activity of pyruvate dehydrogenase complex
function of complex I of pyruvate dehydrogenase and its key component
catalyzes oxidation of NADH and reduction of UQ
- pumps 4 H+
- key component is thiamine
function of complex II of pyruvate dehydrogenase and its key component
catalyzes oxidation of succinate and reduction of UQ
- only membrane inserted enzyme
- no pumping of H+
- key component is lipoic acid
function of complex III of pyruvate dehydrogenase and its key component
oxidizes ubiquinol and reduces cyt C
- 4 H+ pumped for every 2 electrons transferred to cyt c
- key component is FAD
What is cytochrome c?
a protein that shuttles between complexes III and IV
function of complex IV of pyruvate dehydrogenase
catalyzes reduction of O2–>H2O
- 4 electron reduction
- accumulates the 4 electrons from cyt c
- pumps 2 H+/every 2 electrons or 4 H+/each O2
Why can pyruvate dehydrogenase have the same complex III as alpha-KG dehydrogenase?
They have identical substrates and products
What does decarboxylation do?
removes a CO2
When considering standard reduction potentials, which compound will be reduced?
The compound with the more positive standard reduction potential
What role does light energy play in photosynthesis?
used to dissociate water into O2, protons, and high energy electrons
What do amino transferases do?
catalyze synthesis of aspartate and alpha-KG
Where does arginine–>ornithine catalysis take place?
the urea cycle
Why do electrons transported from FADH2 to the electron transport chain produce fewer ATP than electrons transported into complex I from NADH?
because FADH2 enters at complex II which does not pump protons
What does DNP do?
increases rate of NADH oxidation
increases rate of citric acid cycle
can decrease ATP production
*** oxygen consumption unaffected, electron transfer unaffected
characteristics of ubiquinone
soluble in membranes
accepts electrons from complex I
accepts electrons from complex II
citric acid cycle functions
form intermediates like alpha-KG that can be used for amino acid synthesis
generate NADH and FADH2
substrate level phosphorylation of GDP to GTP
why is the conversion of malate and NAD+ to oxaloacetate and NADH favorable?
concentration of oxaloacetate extremely low relative to malate
carnitine purpose
essential for transport of fatty acids across mitochondrial membrane
urea cycle components
amino acids undergo transamination to form glutamate and alpha keto acids
alanine carries ammonia from skeletal muscle to liver
glutamate combines with ammonia to form glutamine which travels to liver through blood stream
characteristics of mitochondrial electron transport
generates most reactive oxygen species and may contribute to aging
functions of ATP synthase
catalyze hydrolysis/synthesis of ATP
certain subunits rotate during synthesis/hydrolysis
release of ATP requires proton gradient
calvin cycle function
NADPH and ATP used to reduce C-O bonds
What decreases energy density?
increasing percentage oxidized bonds
mitochondria processes
citric acid cycle
reduction of O2–>H2O
fatty acid oxidation
how do the pyruvate and alpha-KG dehydrogenase complexes preserve energy?
in a thiol ester bond to co-enzyme A
how is light energy transported out of chloroplast in eukaryotic plant cells?
as chemical energy in dihydroxy acetone phosphate
How many acetyl co-A, NADH, and FADH2 formed from a 12 carbon fatty acid
6 acetyl co-A
5 NADH
5FADH2
what is ATP used for in the urea cycle?
creates a high energy intermediate from bicarbonate so that adding ammonia to the bicarbonate is favorable
glycolysis reactions
NAD+–>NADH
PEP+ADP–>ATP
1,3-bis+ADP–>ATP
which compound produces the most energy if completely oxidized to CO2
ethanol
how much acetyl CoA is formed from 1 glucose going through the glycolysis dehydrogenase complex
2 acetyl CoA
pyruvate dehydrogenase path
pyruvate–>lipoic acid–>FADH2–>NADH
how much CO2, NADH, and FADH2 is produced each turn of the citric acid cycle
2 CO2
3 NADH
1 FADH2
what are the net gains of oxidizing the acetate of acetyl CoA in the citric acid cycle
NADH, CO2, GTP
compounds in urea cycle
aspartate, ATP, carbamoyl phosphate
what is the final electron acceptor of electron transport in the mitochondria?
O2
