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43 Cards in this Set
- Front
- Back
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which process does NOT generate CO2?
A- the Citric acid cycle B- The conversion of pyruvate to lactic acid C- The conversion of pyruvate to acetyl-CoA D- The conversion of pyruvate to ethanol |
B--The conversion of pyruvate to lactic acid.
Both pyruvate and lactic acid are 3 carbon molecules. So NO CO2 is generated. |
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the citric acid cycle converts a molecule of pyruvate into what?
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2 CO2 and H20
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when pyruvate is converted to acetyl-CoA (a 2-carbon molecule), what is generated?
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a CO2
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when pyruvate is converted to ethanol, what is generated?
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CO2
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which of the following is TRUE about the fermentation of glucose?
A- It can occur under aerobic or anaerobic conditions, depending on the products generated B- There is no net yield of ATP C- The hydrogen to carbon ratio of the reactants and products remains the same D- It always generates CO2 |
C- The H:C ration of the reactants and products remains the same.
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can fermentation of glucose occur under aerobic AND anaerobic conditions?
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NO. Fermentation is the degradation of glucose under anaerobic conditions, regardless of the fermentation product (ethanol or lactate)
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when fermentation of glucose occurs, where does the ATP production occur?
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from glcolysis ( the steps up until pyrurvate is made)
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the the fermentation of glucose to lactate generate CO2?
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no.
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Glycogen is degraded in a
A- Phosphorylation rxn B- Hydrolysis rxn C- Dephosphorylation rxn D- phosphorolysis rxn |
D- phosphorolysis rxn
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Glycogen is degraded in a phosphorolysis rxn catalyzed by the enzyme _______ ________. In this rxn, a _____________ linkage joining two glucose residues in glycogen undergoes attack by ____ ____________. A phosphorylation rxn is usually catalyzed by a ________ enzyme and involves the transfer of a __________ group from _______
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glycogen phosphorylase
glycosidic inorganic phosphate Kinase phosphoryl ATP |
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when starch is cleaved into oligosaccharides, how is the glycosidic bond cleaved? What type of rxn?
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by the addition of water. This is a hydrolysis rxn.
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which of the following sugars does NOT get converted to D-glucose before entering the glycolytic pathway?
A- D-Fructose B- Glycogen C- Sucrose D- Lactose |
A- D-fructose
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how does D- Fructose enter the glycolytic pathway?
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it is converted to either fructose 6-phosphate or glyceraldehyde 3-phosphate
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can the disaccharide sucrose get converted to D-Glucose before entering the glycolytic pathway? (the same thing happens with lactose)
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yes. Sucrose will be converted to glucose and fructose (by sucrase)
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which of the following steps occurs during the payoff phase of glycolysis?
A- The conversion of phosphoenolpyruvate to pyruvate B- The conversion of fructose 6-phosphate to fructose 1,6-bisphosphate C- The conversion of glucose 6-phosphate to fructose 6-phosphate D- The conversion of glucose to glucose 6-phosphate |
A- The conversion of phosphoenolpyruvate to pyruvate
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the payoff phase of glycolysis, which ________ ATP, occur during those steps involved in the conversion of __________________ ultimately to ___________. The conversion of __________ to ____________ generates a molecule of ATP and is an example of one of the steps that occurs in the payoff phase of glycolysis
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produces
glyceraldehyde 3-phosphate pyruvate phosphoenolpyruvate pyruvate |
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what can't those other steps be payoff steps?
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because they involve 6-carbon sugars.
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Under what conditions will lactic acid accumulate in skeletal muscle?
A- When citric acid enzymes are depleted B- When ATP is depleted C- When 02 is depleted D- When NADH is depleted |
C-When O2 is depleted
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the enzyme that converts 3-phosphoglycerate to 2-phosphoglycerate is a
A- Transferae B- Kinase C- Mutase D- Phosphorylae |
C- Mutase
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what do mutases do?
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they transfer a functional group from one position to another in the SAME molecule.
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what do transferases do?
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catalyze the transfer of functional groups from one molecule to a DIFFERENT molecule
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Kinases are a type of ________ that transfers __________ groups from ATP to an acceptor nucleophile
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transferase
phosphoryl |
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what do phosphorylases do?
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catalyze reactions in which inorganic phosphate attacks a molecule, resulting in lysis.
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Glycolysis and the pentose phosphate pathway are the same in that
A- They both generate NADPH B- They both generate ATP C- The both involve the oxidation of glucose D- They are reversible |
C-They both involve the oxidation of glucose
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in the oxidation part of the pentose phosphate pathway glucose is oxidized to what?
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ribose 5-phosphate and CO2
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Glycolysis generates ____ molecules of _____ per molecule of glucose, and the pentose phosphate pathway generates ______ molecules of ________ per molecule of glucose
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2. NADH
2. NADPH |
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does glycolysis AND the pentose phosphate pathway generate ATP?
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No. only glycolysis generats ATP (2 per molecule of glucose)
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Both glycolysis and the pentose phosphate pathway are reversible/irreversible processes. In the case of glycolysis, the overall G change is very exergonic, rendering the process essentially _________. The oxidative pentose phosphate pathway that converts ____________ to _______________ is also _____________. To convert D-ribose 5-phosphate back to glucose 6-phosphate requires a different set of reactions catalyzed in the _______________ pentose phosphate pathway
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irreversible
irreversible glucose 6-phosphate D-Ribose 5-phosphate irreversible nonoxidative |
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which of the following reactions is catalyzed by transaldolase?
A- xylulose 5-phosphate +ribose 5-phosphate >< glyceraledyhde 3-phosphate + sedoheptulose 7-phosphate B- ribose 5-phosphate >< xylulose 5-phosphate C- sedoheptulose 7-phosphate + glyceraldehyde 3-phosphate >< erythrose 4-phosphate +fructose 6-phosphate D- xylulose 5-phosphate + erythrose 4-phosphate >< glyceraldehyde 3- phosphate + fructose 6-phosphate |
C.
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What is the role of uridine diphosphate (UDP) in the conversion of galactose to glucose 1- phosphate?
A- its hydrolysis is needed to provide the energy to convert galactose to glucose 1- phosphate B- it donates a phosphoryl group to galactose to generate galactose 1- phosphate C- It serves as a phosphate acceptor D- It serves as a carrier for galactose and glucose. |
D. It serves as a carrier for galactose and glucose.
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UDP functions as a ________-like carrier of hexose groups. Galactose 1-phosphate must be ________ joined to _______ in order to be converted to glucose. UDP-galactose is converted to UDP-glucose by the enzyme ___________________. Later UDP- glucose undergoes a transfer reaction with galactose 1-phosphate to generate ___________ and ___________.
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coenzyme
covalently UDP UDP-glucose 4-epimerase UDP-galactose glucose 1-phosphate |
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the NADPH produced in the pentose phosphate pathway is used
A- to donate electrons to O2 in mitochondria B- to provide reducing power for biosynthetic reactions C- to convert superoxide free radicals into hydrogen peroxide during detoxification D- to provide the energy for catabolic reactions |
B- to provide reducing power for biosynthetic reactions.
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Which of the following is TRUE about gluconeogenesis?
A- In mammals, gluconeogenesis occurs predominately in the liver B- Gluconeogenesis is the pathway by which glucose is converted to glycogen C- The gluconeogenesis pathway is the glycolysis pathway running in the opposite direction D- Plants do not undergo gluconeogenesis. |
A- In mammals, gluconeogenesis occurs predominately in the liver
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Rapidly dividing cells have a high need for nucleotide precursors, which are provided by
A- The cori cycle B- The pentose phosphate pathway C- Glycolysis D- Gluconeogenesis |
B- The pentose phosphate Pathway
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The pentose phosphate pathway converts ______________ to ______ and __________, which are used to make _______ for RNA, DNA, and such conenzmyes as ATP, NADH, FADH2, and CoA
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glucose 6-phosphate
NADPH pentose phosphates nucleotides |
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what does the cori cycle do?
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in converts lactate back to glucose in the liver.
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All of the bypass reactions used in gluconeogenesis
A- require high-energy equivalents B- involve the removal of phosphate groups C- are irreversible D- requires mitochondrial enzymes |
C- are irreversible
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Only the first bypass--the conversion of pyruvate to _________ then to ___________ requires high-______ equivalents. ________ is hydrolyzed in the conversion of pyruvate to oxaloacetate and _______ is hydrolyzed in the conversion of oxaloacetate to PEP
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oxaloacetate
phosphoenolpyruvate (PEP) Energy ATP GTP |
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Only the second bypass (the conversion of fructose 1,6-bisphosphate to_____________) and the third bypass (the conversion of glucose 6-phosphate to _________) involve the ________ of phosphate groups. Both are ________ reactions catalyzed by phosphatase enzymes
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fructose 6- phosphate
glucose removal hydrolysis |
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which bypass requires mitochondrial enzymes?
Pyruvate is transported to the ___________, where the enzyme pyruvate carboxylase converts it to ___________ |
the first bypass--the conversion of pyruvate to oxaloacetate then to PEP
Mitochondria oxaloacetate |
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Mammals cannot convert fatty acids to glucose because
A- they have no pathway for breaking down fatty acids B- they cannot use pyruvate as a precursor of glucose C- The glycolysis pathway is not reversible D- The cannot convert acetyl-CoA to pyruvate |
D- They cannot convert acetyl-CoA to pyruvate
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so mammals cannot convert the catabolite of fatty acids, _________, to ________ which is the usualy starting material for the synthesis of glucose by _______________. Plants, yeast and many bacteria have pathways that convert acetyl-CoA to oxaloacetate, and can therefore use fatty acids for gluconeogenesis. Plants use the ________ cycle to skip the first step of the converstion of pyruvate to oxaloacetate
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Acetyl-CoA
pyruvate gluconeogenesis glyoxylate cycle |
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In all organisms, fatty acids are normally broken down to _________, but in mammals, there is no pathway to convert acetyl-CoA to pyruvate.
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Acetyl-CoA
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