Exam 2 Flash Cards
27 Cards in this Set
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In Eukaryotic cells, glycolysis occurs in the __, and the TCA cycle occurs in the
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cytoplasm; mitochondria
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The pyruvate dehydrogenase complex contains three multimeric enzymes (E1, E2, and E3). All are properties of E1 subunit EXCEPT:
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It binds NAD+ in its active site
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Properties of E2 include:
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It uses thiamin pyrophosphate as a catalytic coenzyme
it oxidatively decarboxylates pyruvate
it transfers an acetyl group to lipoamide of Eta
it forms a hydroxyethyl-TPP intermediate
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10. Which is NOT true of citrate synthase?
A. it catalyzes the first reaction in the TCA cycle
B. it is not regulated
C. OAA and acetyl-CoA bind to the active sites
D. the citrate synthase reaction liberates a relatively large amount of energy
E. all of the above are true
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B
It is not regulated
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In the TCA cycle __ oxidation uses NAD+ as the oxidizing agent while __ oxidation uses FAD as the oxidizing agent
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3; 1
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a-Ketoglutarate dehydrogenase is a multi-enzyme complex analogous to:
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pyruvate dehydrogenase
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The correct sequence of electron transport in the succinate dehydrogenase reaction mechanism is:
A) Coenzyme Q (UQ)
B) FAD
C) iron-sulfur clusters
D) electron transport chain
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B) FAD
C) Iron-sulfur clusters
A) Coenzyme Q
D) ETC
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Which of the following statements regarding the glyoxylate cycle is true?
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two molecules of acetyl CoA can be converted to one molecule of oxaloacetate
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What are the principal allosteric regulatory "signals" controlling the TCA cycle activity
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acetyl-CoA
NADH
NAD+
ATP
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Mammalian pyruvate dehydrogenase is regulated by phosphorylation using the enzyme__ which is allosterically activated by high levels of __ and __.
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pyruvate dehydrogenase kinase; NADH; acetyl-CoA
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The isocitrate lyase catalyzed reaction cleaves isocitrate into
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succinate and glyoxylate
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What is an inhibitor of complex IV?
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cyanide
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The malate-aspartate shuttle transfers ___ from cytosol to matrix while ____ moves from matrix to cytosol
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malate; a-ketoglutarate
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Where does the energy that drives ATP synthesis come from?
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the proton gradient
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the reaction of photosynthesis whereby light energy is transduced into chemical energy uses ___as a source of carbon; and produces ___
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CO2; hexose
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light-dependent electron flow with the production of ATP can occur without the formation of NADPH. This process is called ___, which involves only one of the photosystems, ____.
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cyclic photophosphorylation; P700
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Characteristics of chlorophyll include all EXCEPT:
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iron-containing porphyrin
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which of the following statements about the light reactions of photosynthesis is true?
There are two distinct photosystems, linked together by a mechanism similar to electron transport.
The source for electrons is located in the stroma of the thylakoid.
The Mn complex is the primary el…
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1) there are two distinct photosystems linked together by a mechanism similar to electron transport.
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the light reactions in photosynthetic plants:
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involve the splitting of two water molecules to produce molecular oxygen
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how many photons of light must be absorbed by PSII for the oxidation of 2 water molecules to form one oxygen molecule?
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4
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All are properties of both the P700 and P680 reaction centers EXCEPT:
contain chlorophyll dimers.
are electron donors.
are activated by visible light.
are involved in light-driven O2 evolution.
all are properties.
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4) are involved in light-driven O2 evolution
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The proton-motive force is composed of a ____ and a ____, and in photophosphorylation the ____ is greater.
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membrane potential; pH gradient; pH gradient
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Cyclic photophosphorylation takes place when
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NADPH/NADP+ ratio is high, energy is used in generating ATP
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light-dependent electron flow with the production of ATP can occur without the formation of NADPH. This process called __, which involves only one of the photosystem, ___.
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cyclic photophosphorylation; p700
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___and ___ are produced in the light reactions of photosynthesis which are used to convert __ to __
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ATP; NADPH; carbon dioxide; sugar
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Although the ratio of carboxylase to oxygenate activity of rubisco is about ___ TO ONE, the oxygenate activity diminishes plant productivity because of the loss of ___
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3-4; ribulose-1,5-bisphosphate
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The essential enzyme in C-4 plants used to conserve CO2 and avoid photosphorylation is:
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PEP carboxylase
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