Biochemistry Test 3 Sapling Review – Flashcards
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What terms describe the relationship between a-D-glucose and B-D-glucose
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epimers, diastereomers, anomers
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What terms describe the relationship between a-D-glucose and a-D-mannose?
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epimers, diastereomers
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What terms describe the relationship between a-D-glucose and a-L-glucose
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enantiomers
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Which of the following sugars show mutarotation?
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mannose, maltose, fructose
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Oxidation of carbon 6 of a hexose to the level of a carboxylic acid
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uronic acid
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oxidation of the aldehyde carbon of a sugar to the level of a carboxylic acid
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aldonic acid
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Gluconic acid is an example of this type of sugar derivative
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aldonic acid
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Muramic acid is an example of this type of sugar derivative
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amino sugar
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fucose is an example of this type of sugar derivative
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deoxy sugar
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lactose and trehalose are ________
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disaccharides
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trehalose is a _____ sugar
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non-reducing
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lactose and trehalose are joined by a ______
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O-glycosidic bond
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A reducing sugar must have a
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free anomeric carbon
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consists of N-acetylglucosamine residues
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chitin
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a storage form of fuel for plant cells
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starch
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functions in fuel storage in animal cells
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glycogen
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provides structural support for animals, most conspicuously in the exoskeletons of arthropods
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chitin
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the storage form of glucose in animals
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glycogen
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provides structural support for plants
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cellulose
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made up of two glucose polysaccharides - amylose and amylopectin
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starch
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starch, glycogen, cellulose, and chitin are examples of
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homoglycans
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plant polysaccharide that is easily digested by humans
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starch
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Possible components of glycosaminoglycans
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N-acetylglucosamine and uronic acid
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Glycosaminoglycans are _______
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heteroglycans
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chondroitin sulfate and keratan sulfate are examples of
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glycosaminoglycans
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function of lectins
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recognition of specific oligosaccharide structures
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Structural variability in oligosaccharides specifying interactions at cell surfaces.
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sugar code
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Polymer of D-Glucuronic acid (GlcA) and N-acetylgalactosamine (GalNAc4S)with β(1 3) linkages, found in ligaments and the walls of the aorta.
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chondroitin sulfate
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Lectin molecules specifically bind to oligosaccharide molecules in absence of this terminal residue.
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sialic acid
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Contains β(1 4) glycosidic bond between N-acetylglucosamine and N-acetylmuramic acid.
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peptidoglycan
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L-iduronic acid (IdoA2S) and glucosamine (GlcNS3S6S) α(1 4), found in mast cells.
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heparin sulfate
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Polymer of galactose and N-acetylglucosamine with β(1 4) linkages, found in nails and hooves.
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keratan sulfate
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net equation of glycolysis
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glucose+2ADP+2Pi+2NAD+ -> 2pyruvate+2ATP+2NADH
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reaction 1 of the first step of glycolysis is :
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nonspontaneous
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Net chemical equation of Step 1 of glycolysis
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glucose+ATP -> glucose-6-phosphate+ADP
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which step of glycolysis is a redox reaction?
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step 6
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these steps are catalyzed by a transferase
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1,3,7,10
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these steps are catalyzed by an isomerase
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2,5,8
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these steps are catalyzed by a lyase
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4,9
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10 enzymes of glycolysis
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hexokinase, phosphohexose isomerase, phosphofructokinase, aldolase, triosephosphate isomerase, triose phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase, pyruvate kinase
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in the first reaction of glycolysis, glucose is converted to _______. The phosphate comes from ATP
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G6P
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the main control point of glycolysis
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3
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negative inhibitors of step 3 of glycolysis
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ATP, citrate
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positive effectors that activate phosphofructokinase-1
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ADP, AMP
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loss of allosteric binding site for ATP in pyruvate kinase would _____ the rate of glycolysis
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increase
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loss of regulatory binding site for ATP in phosphofructokinase would ______ the rate of glycolysis
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increase
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loss of allosteric binding site for AMP in phosphofructokinase would _____ the rate of glycolysis
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decrease
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loss of binding site for fructose, 1,6- bisphosphate in pyruvate kinase would _____ the rate of glycolysis
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decrease
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plays an important role in liver regulation of blood glucose level, not sensitive to inhibition by G6P
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glucokinase
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when blood glucose is low, will cause cells to trap glucose by phosphorylation
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hexokinase
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pyruvate is dephosphorylated by pyruvate carboxylase to become
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oxaloacetate
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net equation of gluconeogenesis
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2pyruvate+2NADH+4ATP+2GTP -> glucose+2NAD++4ADP+2GDP+6Pi
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Which step of gluconeogenesis is the main negative control point?
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8
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Which inhibits the enzyme for step 8 in gluconeogenesis
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insulin, AMP, fructose-2,6-bisphosphate
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activation of PFK-2 activates ______
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glycolysis
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inhibition of PFK-2 activates
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gluconeogenesis
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increased levels of cAMP activates ______
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gluconeogenesis
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increased glucagon levels activates ______
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gluconeogenesis
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Increased levels of fructose 2,6-bisphosphate activates
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glycolysis
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the substrate for the pentose phosphate pathway
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G6P
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Which molecule controls the rate of the pentose phosphate pathway
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NADP+/NADPH
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Enxyme that catalyzes the reaction influenced by NADP+/NADPH
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glucose-6-phosphate dehydrogenase
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Galactose derivative that can enter glycolysis
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G6P
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Fructose derivative that can enter glycolysis
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DHAP and G3P
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a proton is transferred between enzyme and substrate
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acid-base catalysis
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may use amino acids such as aspartate or lysine for protonation or proton abstraction
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acid-base catalysis
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a covalent bond forms between enzyme and substrate
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covalent catalysis
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uses a nucleophilic functional group
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covalent catalysis
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two-part catalytic process
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covalent catalysis
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catalyst may participate in redox reactions by changes in the oxidation state
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metal ion catalysis
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retains its original form after reaction occurs
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catalyst
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interconvert between a more active form and less active form
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allosteric enzymes
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inhibitor structure resembles substrate structure
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reversible competitive
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inhibitor binds noncovalently at active site
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reversible competitive
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inhibitor binds noncovalently at site other than active site
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reversible noncompetitive
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inhibitor binds covlaenty and permanentyl at site other than active site
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irreversible
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structurally similar to substrate
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competitive inhibitor
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when present, vMAX of enzyme is unaffected
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competitive inhibitor
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prevents substrate from binding enzyme
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competitive inhibitor
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when present, Km of enzyme will decrease
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uncompetitive inhibitor
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binds enzyme-substrate complex only
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uncompetitive inhibitor
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binds either enzyme or enzyme-substrate complex
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mixed inhibitor
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when present, Km of enzyme will either increase or decrease
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mixed inhibitor
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inhibitor may permanently modify an enzyme
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irreversible inhibition
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DIPF permanently modifies the hydroxyl group of a Ser residue at the active site
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irreversible inhibition
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binding by the inhibitor increases Km but not Vmax
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competitive inhibition
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binding by the inhibitor increases Km but decreases Vmax
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mixed inhibition
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forms part of the acetyl-SCoA, which is part of the citric acid cycle
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coenzyme A
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derived from the vitamin pantothenic acid
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coenzyme A
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derived from the vitamin nicotinamide
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NAD+
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accepts two electrons and one proton when it is reduced
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NAD+
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derived from the vitamin riboflavin
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FAD
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accepts two hydrogen atoms when it is reduced
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FAD
