Test 3 Review: Bioinformatics Flashcards
Where does glycolysis occur?
Cytosol
Where does oxidation of pyruvate occur?
Mitochondrial matrix
Where does the Krebs cycle occur?
Mitochondrial matrix
Where does the electron transport chain and ATP synthase occur?
Inner mitochondrial membrane
Is glycolysis anaerobic or aerobic?
Anaerobic
How many of the original carbons of glucose are left at the conclusion of glycolysis?
6
How many of the original carbons of glucose are left after the oxidation of pyruvate?
4
How many of the original carbons of glucose are left after the Krebs cycle?
0
What are the three types of energy currency in cells?
ATP
“Reducing power”
Electrochemical gradients
What are the molecules that make up “reducing power”?
NADH and FADH2
How does an energy currency work?
Used to drive energetically unfavorable reactions
How does substrate-level phosphorylation work?
A high-energy phosphate group is enzymatically transferred from a substrate to ADP to make ATP
How does oxidative phosphorylation work?
The ATP synthase uses the energy of the proton gradient to combine ADP and Pi to make ATP.
With what membrane is the ATP synthase associated in the mitochondrion?
Inner mitochondrial membrane
What is the directionality of the electrochemical gradient the mitochondrion uses to drive ATP synthesis?
High proton concentration (low pH) in intermembrane space
Low proton concentration (high pH) in the matrix
What kind of movement is associated with ATP synthesis?
Rotation
What is the final acceptor of electrons in the mitochondrial electron transport chain?
O2
What happens to O2 when it receives the electrons in the electron transport chain?
It is reduced
What is the product of the reduction of O2 in the electron transport chain?
H2O
How is heat generated in bioenergetics?
By uncoupling the electron transport chain from ATP synthesis – energy of electrons is lost as heat
What kind of energy does the ATP synthase use when rotating?
Mechanical energy
Action Spectrum
extent of a light-dependent reaction vs wavelength of light
Absorption Spectrum
absorbance of a compound vs wavelength of light
How are action spectra and absorption spectra related?
A light-absorbing compound involved in a light-dependent reaction would have an absorption spectrum that overlaps the action spectrum
How is chlorophyll organized in the chloroplast?
Organized in light-harvesting complexes
Where would you find the light-harvesting complexes?
Thylakoid membrane
What ions are critical for the function of chlorophyll and the water-splitting reaction?
Mg2+ for chlorophyll
Mn2+ for water-splitting reaction
How many photons are required to drive the water-splitting reaction to completion?
4
With what photosystem is the water-splitting reaction associated?
Photosystem 2
What connects Photosystem 2 to Photosystem 1?
Electron transport chain
Specifically the cytochrome b6/f complex
What is the role of the cytochrome b6/f complex?
Builds H+ gradient used by ATP synthase to make ATP
Where is the cytochrome b6/f complex located?
Thylakoid membrane
Where are the photosystems located?
Thylakoid membrane
Non-Cyclic Phosphorylation
one-way flow of electrons from H2O to PS2 to PS1 and eventually reduced molecules
Cyclic Photophosphorylation
PS1 operates alone, feeding energized electrons to the cytochrome b6/f complex to contribute to the H+ gradient and make ATP
Why does cyclic photophosphorylation matter?
Calvin cycle requires more ATP than NADPH, but non-cyclic phosphorylation produces them in a 1:1 ratio. This reduces this imbalance.
With what membrane is the ATP synthase associated in the chloroplast?
Thylakoid membrane
What is the directionality of the electrochemical gradient it uses to drive ATP synthesis?
High [H+] in the thylakoid membrane
Low [H+] in the stroma
Direction of movement is from thylakoid membrane to stroma
Compare ATP synthesis in chloroplasts and mitochondria: what are the equivalent membranes and compartments?
Inner mitochondrial membrane and thylakoid membrane
Matrix/stroma and intermembrane space/thylakoid lumen
What is the ultimate source of electrons in photosynthesis?
H2O
What is the energy level of the electrons in photosynthesis?
Low
What accepts electrons in photosynthesis, and why is it able to do so?
P680 – strongest oxidizer in nature
Transient Starch
Starch that turns over daily
Where is transient starch stored?
Stored as starch grains in stroma of chloroplast
How is transient starch used by plant cell?
Used for basic metabolic functions
Where is the Calvin cycle located?
Chloroplast stroma
Is the Calvin cycle an energy-yielding or an energy-consuming reaction?
Energy consuming
What is the CO2 fixation enxyme?
Rubisco
What other reaction (other than fixing CO2) does the CO2 fixation enzyme inherent to the Calvin cycle catalyze?
An oxygenase reaction
Photorespiration
oxygenase reaction catalyzed by rubisco; recovery pathway that detoxifies toxic glycolate product of that reaction, recovering lost 3-PGA
What is the cost of photorespiration?
Loss of one of the fixed carbons and consumption of O2
What organelles are involved in photorespiration?
Chloroplast, peroxisome, mitochondrion
CO2-Concentration Mechanisms (CCM)
overall term for strategy plants and other organisms have evolved to reduce photorespiration
