Chapter 13/14 Flashcards
Differentiate between the mechanisms of ATP production by glycolysis and oxidative phosphorylation.
Glycolysis breaks down glucose to produce ATP, whereas Oxidative phosphorylation uses proton gradient to synthesize ATP
Recall the activated carriers, generated by the citric acid cycle, which will transfer high-energy electrons to the electron transport chain.
NADH & FADH2 transfer e-
Explain which way electrons flow in the electron transport chain.
Electrons move through the electron transport chain from a higher to lower energy state
Review the membrane potential and pH gradients across the inner mitochondrial membrane, and state in which direction it is energetically favorable for protons to flow.
-protons will flow in the direction towards the higher pH (less protons) and more negative membrane potential
-matrix side becomes more (-) and intermembrane becomes more (+).
-Its favorable to flow back to the matrix.
Explain how ATP synthase acts as a motor to convert the energy of protons flowing down an electrochemical gradient into the chemical bond energy in ATP and the conditions under which ATP synthase will act as a proton pump and hydrolyze ATP.
the passage of proteins through the carrier causes the carrier and its stalk to spin rapidly (motor) and as the stalks rotate, it rubs against proteins in the enzymes stationary head, altering their conformation and causing them to produce ATP. a mechanical deformation gets converted into the chemical-bond energy of ATP
Outline how the electrochemical proton gradient is used to drive the transport of metabolites across the inner mitochondrial membrane in eukaryotic cells
P+ gradient is used to drive coupled transport processes, such as pyruvate and phosphate.
Compare where electrons donated by NADH and FADH2 enter the respiratory chain.
-NADH: NADH dehydrogenase complex (2.5 ATP)
-FADH2: membrane-embedded mobile carrier ubiquinone (1.5 ATP)
Identify the main source of the protons pumped across the inner mitochondrial membrane by the electron transport chain and summarize how electron carriers are able to transfer a proton from one side of the membrane to the other.
-Water
-The electron carrier must be oriented in the membrane in such a way that it accepts an electron-along with a proton from water. One one side of the membrane and then realse a prton on the other side of the membrane when it pasues an electron on to the next elecron carruer molecule in the chain
Outline the events that take place in stage 1 of photosynthesis (light dependent reactions) and indicate where these reactions occur.
-Called the light dependent reaction
-This stage uses water and changes light enery from the sun into chemical energy stored in ATP and NADPH
Review the events that take place in stage 2 of photosynthesis (light independent reactions, Calvin cycle) and indicate where these reactions occur.
-The reacton occurs in the thylakoids and the stroma
-In the second stage ATP and NADPH are used to convert the 3-PGA molecules into moelcules of three-crabon sugar, glyceraldehyde-3-phospahte(G3P)
Summarize how light energy, captured by a chlorophyll molecule in an antenna complex, is transferred to the chlorophyll special pair in the reaction center.
Once light energy has been captured by a chlorophyll molecule in an antenna complex, it will pass randomly from one chlorophyll molecule to another until it gets trapped by a chlorophyll dimer called the special pair, located in the reaction center. The chlorophyll special pair holds its electrons at a somewhat lower energy than the antenna chlorophylls, so the energy transferred to it from the antenna gets trapped there. Note that in the antenna complex, it is energy that moves from one chlorophyll molecule to another, not electrons.
Differentiate between photosystems I and II, indicate the electron carriers to which they transfer their high-energy electrons, and state the source of the electrons that replace those donated by their chlorophyll special pairs.
Photosystems 1 captures energy from the sun. The reaction ceneter of this photosystem passes its high-energy electrons to a different mobile electron carrier, called ferredoxin, which brings them to an enezyme that uses the eletrons to reduce NADP+ to NADPH. It is the combined action of these two photosystems that produces both the ATP (photosystem II) and the NADPH (photosystem I) required for carbon fixation in stage 2 of photosynthesis.
Compare the redox potentials of oxygen/water, oxidized/reduced nicotinamide adenine dinucleotide phosphate, plastoquinone, plastocyanin, and ferredoxin, and indicate which way electrons will flow.
The redox potential goes from low to high with the lowest electron affinity in NADH passing its electrons to NADH dehydrogenase which has a slightly higher electron affinity, and so on and so forth with O2 having the highest electron affinity within the electron transport chain.
Identify the molecules that provide the energy to convert carbon dioxide into sugars.
ATP and NADPH
Recall the role that Rubisco and ribulose 1,5-bisphosphate plays in the carbon fixation cycle.
ribulose 1,5-bisphosphate is the molecule that the carbons from CO2 are added to in the calvin (carbon fixation) cycle
