Biochem Final

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Biochem Final
2011-12-03 23:15:27
Old given questions

test questions
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  1. The three-dimensional structure of macromolecules is formed and maintained primarily through non-covalent interactions. What is NOT considered a non-covalent interaction?
    Carbon-carbon bonds
  2. What biomolecule(s) present in all living organisms play a role in signalling?
    Proteins and lipids
  3. Enzymes are biological catalysts that enhance the rate of reaction by:
    decreasing the activation energy
  4. HO-CH2-CH2-CH=O
    What functional groups are present on this molecule?
    Hydroxyl and aldehyde
  5. A. Thymidine is a component of DNA
    B. Thymidine is a component of RNA
  6. Which of the following is a similarity between all prokaryotes and all eukaryotes?
    1) Both contian DNA in a nucleus
    2) Both contain certain of the same membrane bound organelles (like mitochondria, Golgi complexes etc)
    3) Both have cytoplasm
  7. What is the [OH+] concentration in a urine sample that has a pH of 6?
    10-8 M
  8. What organelle(s) has a double membrane?
    • Nucleus
    • Mitochondria
  9. Extracellular material is taken into the cell via which process?
  10. What is the Henderson-Hasselbach equation?
    pH=pKa+log ([A-]/[HA])
  11. What property of water is important for biological interactions
    The polarity of water
  12. At pH 7, the amino acid Arginine would be charged as follows (pKs are alpha-carboxylate -1.82, alpha-amino -8.99, guanidine -12.48)?
    -1 alpha-carboxylate, +1 alpha-amino, +1 guanidino; +1 net charge
  13. What is the best description of the central dogma of molecular biology?
  14. If the free energy change (Change in G) for a reaction is -46.11 kJ/mol, the reaction is:
  15. What happens to nonpolar molecules in water?
    They aggregate together
  16. What is true under the following conditions: The enzyme concentration is 5nM, the substrate concentration is 5mM, and the Km is 5uM?
    The enzyme is saturated with substrate
  17. Allosteric activators bind to enzymes
    And stabilized the "R-state", which has an enhance substrate affinity
  18. As the pH of its surrounding environment decreases from 7.4 to 7.0, protonation of particular _____ residues in hemoglobin allows the formation of salt bridges that stabilize the _____ state of the quaternary structure, resulting in _____ oxygen binding affinity.
    His; T; decreased
  19. What charged group(s) are present in glycine at a pH of 7?
    • -NH3+
    • -COO-
  20. What is true of cystine (not cysteine)?
    Cystine forms when the -CH2-SH side chain is oxidized to form a CH2-S-S-CH2- disulfide bridge between two cystines
  21. The order of amino acids in a polypeptide chain is HLAWCT. Which of the following is the exact match if the same polypeptide chain were to be rewritten in a different format?
  22. Key properties of proteins include:
    • A wide range of functional groups
    • An ability to possess either rigid or flexible structures as dictated by functional requirments
    • The ability to interact with other proteins
  23. The following data were obtained in a study of an enzyme known to follow Michaelis-Menten kinetics:
    VO (umol/min) Substrate concentration (mM)
    What is the Km for this enzyme?
    • 2mM
    • Build a graph Km half of VO max
  24. The chirality of an amino acid results from the fact that its alpha-carbon:
    is bonded to four different chemical groups
  25. Which is not amound the six internationally accepted classes of enzymes?
  26. A (an) _____ in 2,4-BPG levels would lead to a (an) _____ oxygen affinity of hemoglobin.
    • Increase; decrease
    • decrease; increase
  27. The Henderson-Hasselbalch equation is pH=pKa+log[A-]/[HA]. What is the base to the acid ratio if the equation is simplified to pH=pKa + 1?
  28. What conclusion can be drawn concerning an inhibitor if the Vmax is the same in the presence and absence of the inhibitor?
    The inhibitor has a structure that is very similar to the substrate
  29. What all must be attached to the alpha-carbon?
    • H group
    • COO- group
    • NH3+ group
    • Amino group
  30. Protein S will fold into its native conformation only when protein Q is also present in the solution. However, protein S does not influence the fold of protein Q. Protein Q, therfore, may function as a ____ for protein S.
  31. The enzyme Alcohol Dehydrogenase (ADH) requires NAD+ for catalytic activity. In the reaction catalyzedd by ADH, an alcohol is oxidized to an aldehyde and the NAD+ is reduced to NADH and dissociates from the enzyme. The NAD+ is functioning as a:
  32. Of the 20 strandard amino acids, only _____ is not optically active. The reason is that its side chain ______.
    Glycine, is a hydrogen atom
  33. Of the following, which is NOT true for the secondary protein structure of alpha-helix?
    1) It is right-handed
    2) A hydgrogen bond forms between the carbonyl oxygen of the nth amino acid residue and the NH group of the (n+4)th amino acid residue
    3) Proline is typically not found in the alpha-helix
    4) There are 3.6 amino acids per turn
    5) Ther is a requirement for glycine every third amino acid residue
    There is a requirement for glycine every third amino acid residue.
  34. At the isoelectric pH of a tetrapeptide
    The total net charge is zero
  35. What is the approximate mass of a protein containing 200 amino acids?
    22,000 daltons
  36. The compound that consists of ribose linked by a glycosidic bound to an adenine is:
  37. Which of the following amino acid resideues would most likely be buried in the interior of a water soluble, globular protein? Asp, Ser, Lys, Phe, Gln
  38. What best represents the backbone arrangement of a dipeptide?
  39. Enzyme activity in cells is controlled by processes including:
    • Covalent modification
    • Feedback regulation
    • Zymogen activation
  40. A. "Alcohol Intolerance" is caused by a mutation that converts a low-Km mitochondrial Aldehyde dehydrogenase to a high-Km enzyme.
    B. "Alcohol Intolerance is caused by a mutation that converts a low-Km cytoplasmic Aldehyde dehydrogenase to a high-Km enzyme.
  41. The Km is:
    Equal to the substrate concentration when the reaction rate is half its maximal value
  42. Match:
    A. Uncompetitive inhibition
    B. Noncompetitive inhibition
    C. Allosteric inhibition
    D. Suicide inhibition
    a. inhibitors binds irreversibly to the enzyme
    b. Km-unaffected; Vmax-affected
    c. Km-affected; Vmax unaffected
    d. Both Km and Vmax affected
    e. inhibitor binds irreversibly to the ES complex
    f. caused by end-product of a pathway
    g. caused by the initial substrate of a pathway
    • Uncompetitive inhibition--> Both Km and Vmax affected
    • Noncompetitive inhibition-->Km-unaffected; Vmax-affected
    • Allosteric inhibition-->caused by end-product of a pathway
    • Suicide inhibition-->inhibitors binds irreversibly to the enzyme
  43. Match:
    A. Methionine
    B. Aspartic acide
    C. Threonine
    D. Lysine
    a. carries a hydroxyl group
    b. negatively charged at cellular pH
    c. required to make dopamine
    d. sulfer containing amino acid
    e. positively charged at cellular pH
    f. forms disulphide linkage
    • Methionine-->Sulfer containing amino acid
    • Aspartic acid--> Negatively charged at cellular pH
    • Threonine-->Carries a hydroxyl group
    • Lysine-->positively charged at cellular pH
  44. The enzyme that is capable of synthesizing RNA from a DNA template is called?
    RNA polymerase
  45. _______ is a membrane bound organelle, filled with digestive enzymes, present in eukaryotic cells.
  46. The prosthetic group that is essential for the function of hemoglobin and myglobin is "heme". The organic part of heme is called:
  47. The straight-line enzyme-kinetic plot of the 1/Vo versus 1/[S] is called:
    • Lineweaver-Burk
    • (double reciprical plot)
  48. The sulfa drug, sulfanilamide, is an example of what kind of inhibitior?
  49. The enzyme that is diagnostic of Myocardial Infarction is
    CK, creatine kinase
  50. Competitive inhibition is an allosteric regulation?
    False, it is not!
  51. The cofactor used by the enzyme Prolyl hydroxylase is:
    Vitamin C
  52. Plataue on a graph of pH on x axis and added OH equi alents represents?
    the region where the net charge on glycine is zero
  53. Fructose in solution can cyclize to (a)
    Both pyranose and furanose ring forms
  54. A. Lipid-anchored membrane proteins are found in the middle of the lipid-bilayer.
    B. Peripheral membrane proteins are present both on the external and the internal side of the membrane bilayer.
  55. What monosaccharide is NOT an aldose?
  56. Digitalis is a cardiotonic sterioid that does not act like a steroid. Instead its function is to inhibit____.
    The Na+-K+ pump
  57. Maltose is composed of two molecules of ______ linked together by ______ glycosidic bond.
    Glucose; alpha-1,4 linkage
  58. Are G proteins intergra membrane proteins?
    No they are not.
  59. A _______is a stereoisomer that is not a mirror image around all the asymmetric C-atom.
  60. ________ is a common hydrophobic group attached to proteins, making it easier for the protein to be anchored to cell membrane.
  61. Glycosylation of proteins occurs where?
    • Golgi
    • Endoplasmic Reticulum
  62. Which of the following is NOT a main function of lipids?
    Cell Signalling
    Fuel Source
    Structural regidity of the cytoskeleton
    Membrane componet
    Structural rigidity of the cytoskeleton
  63. When twyo carbohydrates are epimers:
    They differ only in the configuration around one arbon atom
  64. Which of the following is NOT involved in signal transduction through the epinephrine receptor?
    Cyclic AMP
    Cyclic GMP
    Cyclic GMP
  65. Example of a mechanism by which a signaling process might be very specifically terminated:
    Protein dephosphorylation by phosphatases
  66. What would an Enanimer of this sugar look like?
    • CHO
    • HO--H
    • H--OH
    • HO--H
    • HO--H
    • CH2OH
  67. The type of transporter which relies on the driving energy of a gradient
    Facilitated Diffusion and Simple Diffusion
  68. D-Glucose is called a reducing sugar because it undergoes an oxidation-reduction reaction at the anomeric carbon. One of the products of this reaction is:
  69. The low incidence of protein or lipid flip-flop in a membrane preserves
    Membrane asymmetry
  70. Glycogen and starch both serve primarily as structural elements in cell walls.
  71. A. The reaction between one molecule of alcohol and one molecule of aldehyde yiels acetal.
    B. The reaction between one molecule of alcohol and moleculue of aldehyde yields hemikeltal.
    • A=B
    • False
  72. The enzyme responsible for induction of the phosphoinositide cascade is?
    Phospholipase C
  73. A saccharide that has free aldehyde group is called a_____
    Reducing sugar
  74. What enzyme activates the zymogen, trypsinogen?
  75. What is the structure of D-galactose?
    • CHO
    • H--OH
    • HO--H
    • HO--H
    • H--OH
    • CH2OH
  77. What is released by the upper intestine and increases zymogen secretion?
  78. In disaccharides attached 1,4-linkage
    Only ring B is in equilibrium with an open chain form
  79. A fatty acid designated as 20:0 is _______, while one that is designated 20:3 is ________.
    Saturated, Unsaturated
  80. Dietary triacylglycerols are digested as a result of
    • Lipase action
    • Bile Salts
    • Micelle Formation
    • Diffusion and absorption by intestinal cells
  81. ATP contains one _____ bond and two _____ bonds.
    Phosphoester; phosphanhydride
  82. Catabolic pathways are inhibited by a ____ energy charge and the anabolic pathways are stimulated by a _______ energy charge.
    High; high
  83. During glycolysis, glucose 1-phosphate is converted to fructose 6-phosphate in two successive reactions:
    Glucose 1-phosphate-->glucose 6-phosphate (-7.1kJ/mol)
    Glucose 6-phosphate-->fructose 6-phosphate (+1.7 kJ/mol)
    What is the overall delta G of the reaction
    -5.4 kJ/mol
  84. The polar head group of cholesterol is:
    The hydroxyl group
  85. Phosphoinositide Kinase is an inracellular enzyme whose substrate is PIP2. The following product(s) are generated from PIP2 by the action of this kinase.
    diacylglyercol and inositol 1,3,5-triphosphate
  86. The double bond is located where in an omega-3 fatty acid
    3 away from the omega (last carbon)
  87. The fluidity of the lipid side chains in the interior of a bilyaer is generally increased by:
    An increase in the number of double bonds in fatty acids
  88. All the membrane proteins known as G protiens:
    Hydrolyze GTP
  89. Glucose transport takes place by:
    active transport using the sodium glucose contransporter
  90. Electrons released buring the oxidation of a fuel molecule could NOT be captured by
  91. Match
    B. GalphaI
    C. GalphaQ
    D. Akt
    a. Cholecystokinin
    b. pertussis toxin
    c. choleragen
    d. ras signaling
    e. insulin signaling
    f. EGF signalling
    • A.GalphaS-->Choleragen
    • B. GalphaI-->pertussis toxin
    • C. GalphaQ-->Cholecystokinin
    • D. Akt-->Insulin signaling
  92. Match
    A. Heparin
    B. Lectins
    C. Glycolipid
    D. Phospholipid
    a. cardiolipin
    b. glycosaminoglycan
    c. galactosylceramide
    d. homoglycan
    e. carbohydrate-binding proteins
    • A. Heparin-->glycosaminoglycan
    • B. Lectins-->carbohydrate-binding proteins
    • C. Glycolipid-->Galactosylceramide
    • D. Phospholipid-->Cardiolipin
  93. These organisms use energy from sunlight and convert it to chemcial energy ______
  94. When the carbohydrate portion is attached to a serine residue in a glycoprotein, it is referred to as an _______ glycoprotein.
  95. _________ is a membrane lipid composed of sphingosine, fatty acid and a simple sugar.
  96. The receptor protein for insulin has an extracellular binding region for insulin and an intracellular domain with enzymatic activity. The protein is an example of what kind of membrane protein?
    Transmembrane protein
  97. _______ is the membrane protein that catlyzes the conversion of ATP to cAMP.
    Adenylate Cyclase
  98. Limit-dextrins are derived from starch after a-amylase treatment. The reason for the appearance of this partially digesterd material is _______
    alpha 1,6-glycocidic linkage
  99. The influenza virus recognizes _____ residues of glycoproteins present on cell surface.
    Sialic acid
  100. The common name of hexadeconic acid is ______
  101. ________inhibits prostaglandin H2 synthase-1 by blocking the channel through which the substrate, arachidonate, travels.
  102. Mutation of a key tyosine residue in the cytoplasmic domain of the insulin receptor would NOT lead to binding of insulin to the receptor.
  103. Match
    A. (iduronic acid + GalNAC)n
    B. (GalNAc)n
    C. B-D-Galactose + a-D-glucose
    D. (D-Glucuronic acid + N-acetylgalactosamine)n
    a. heparin
    b. chitin
    c. chondroitin sulphate
    d. lactose
    e. dermatan sulphate
    f. chondroitin sulphate
    • A. (iduronic acid + GalNAC)n-->Dermatan sulphate
    • B. (GalNAc)n-->Chitin
    • C. B-D-Galactose + a-D-glucose-->Lactose
    • D. (D-Glucuronic acid + N-acetylgalactosamine)n-->Chondroitin sulphate
  104. Which of the listed leads to the most direct production of ATP by substrate-level phosphorylation?
    Glyceraldehyde 3-phosphate to 3 phosphoglycerate
  105. How many net moelcules of ATP are generated in the conversion of fructose 6-phosphate to one lactate and one pyruvate in the presence of aspartate-malate shuttle?
  106. Mutases are described as:
    enzymes that catlyze the transfer of phosphoryl groups from one part of a substrate molecule to another
  107. A. Aerobic breakdown of glucose by the glycolytic pathway in muscles results in 2 molecules of pyruvate.
    B. Aerobic breakdown of glucose by the glycolytic pathway in RBCs results in 2 molecules of pyruvate
  108. The conversion of isocitrate to fumarate in the TCA cycle:
    Requires thiamine pyrophosphate
  109. Glycogen phosporylase a can be inhibited by covalent modification and allosteric regulation. Which of the following inhibits phosphorylase a by binding to an allosteric site:
  110. What is substrate level phosphorylation?
    ATP synthesis when the phosphate donor is a substrate with high phosphoryl transer potential
  111. Gluconeogenesis is pretty much glycolysis in the opposite direction except for few enzymatic reactions. What is shared?
    Glyceraldehyde 3-P +Pi--> 1,3 bisphosphoglycerate
  112. PDH (pyruvatedehydrogenase) phosphatase deficiency results in which condition
    Elevated lactate levels
  113. The synthesis of glucose from pyruvated by gluconeogenesis:
    Requires the participation of biotin
  114. Which substrate is a good source for blood glucose in an individual with glycogen storage disease type I?
    Dietry glycogen
  115. To reduce one molecule of O2, __ electrons must be passed through the electron transport chain and ___ molecules of NADH are oxidized?
  116. Reaction that is unique to gluconeogenesis?
    Pyruvate to oxaloacetate
  117. Glycogen phosphorylase is ____ (more,less) active when phosphorylated, and it is _____ (activated, inhibited_ by glucose 6,phosphate.
    More; inhibited
  118. 2,3-bisphosphoglycerate is:
    Essential for the efficient release of )2 from hemoglobin
  119. During exercise, muscle cells need continuous supply of ATP to support muscle contraction. What mechanism does NOT contribute to the increase in glycolysis in muscle during prolonged exercise?
    Activation of phosphorylase b by phosphorylation in response to glucagon
  120. What change would NOT occur on treatment of respiring miitochondria with 2,4-dinitrophenol?
    • Decrease in the rate of ATP synthesis
    • Increase in the rate of fuel consumption
    • Increase in the rate of oxygen consumption
    • Increase in heat production
  121. What viatmin or coenzyme does not participate in the oxidative decarboxylation of pyruvate?
  122. What is the net ATP yield from aerobic glycolysis (including the ones from NADH) in the presence of the gylcerol-3-phosphate shuttle
  123. What is the energy provider for the metabolic conversion of oxaloacetate to phosphoenolpyruvate, which is catlyzed by PEP carboxykinase
    hydrolysis of GtP--> GDP+Pi
  124. Correct path taken by a pair of electrons as it travels down the electron-transport chain.
    • NADH+H+-->complex I-->CoQ-->Complex III-->Cyt C-->complex IV-->O2
    • FADH2-->complex II-->CoQ-->Complex III-->cyt c-->complex IV-->O2
  125. Phosphorylase b, the inacctive enzyme, can be allosterically activated. What physiological conditions renders phoshorylase b back to the inactive state (R to T state)?
    High ATP and high glucose 6-phosphate levels
  126. What leads to increased glycolysis in the liver?
    Increased circulating insulin
  127. What is true about the citric acid cycle?
    The cycle produces 3 moles of NADH, 1 mole of FADH2 and 1 mole GTP per mole of acetyl CoA oxidized to CO2 and H2O
  128. What is true about glycogen synthase?
    It requires a primer of four to eight linked glucose residues.
  129. Epinephrine activates glycogenolysis in the liver by:
    Binding to the adrenergic receptor and stimulating adenylyl cyclase through the action of the G protein
  130. Pyruvate, the end product of glycolysis has several fates depending on cellular conditions. What compound is both an inhibitor of pyruvate dehydrogenase and an activator of pyruvate carboxylase?
    Acetyl CoA
  131. Calcium ion increase in the cytoplasm stimulates muscle contraction and therefore glycogenolysis. Cacium ion binds and leads to the activation of what enzyme in glycogen degration?
    Phosporylase kinase
  132. A potent allosteric activator of phosphofructokinase-1 is ____, which is produced from fructose-6-phosphate by the enzyme _______.
    Fructose-2,6-bisphosphate; phophofructokinase-2
  133. Starting with one mole of succinate and ending with one mole of oxaloacetate, how many maxium moes of ATP could the TCA cycle produce when couple to the electron transport system and ATP synthase (assume the glycerol phosphate shuttle is active)?
  134. A 1-month-old baby showed abnormalities of the nervous system and increased lactic acid in the blood. The total amount of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase were normal, but the total enzyme activity was reduced for both. What is true of the baby?
    The patient appears to have thiamin deficiency
  135. Glycogenolysis in liver contributes to the blood glucose, whereas in muscles does not. Why is muscle glycogen NOT available for maintenance of blood glucose concentration?
    Muscle lacks glucose-6-phosphatase activity, so it cannot form free glucose from glycogen
  136. What would exisit in the most oxidized state in mitochondria treated with antimycin?
    Cytochrome oxidase
  137. What enzyme produces a product used for synthesis of ATP by sustrate-level phosphorylation?
  138. The enzyme complexes associated with oxidative-phosphorylation and the electron transport chain can be classified as _____ proteins.
    Integral membrane
  139. Precursor (on a molar basis) that yields the most glucose?
    1 mole of fructose 6-phosphate
  140. What enzyme is responsible for the following reaction?
    Pyruvate + CoA +NAD+-->acetyl CoA + NADH + H+ +CO2
    Pyruvate dehydrogenase
  141. What DECREASES the oxidation of acetyl CoA by the TCA cycle?
    a low NAD+/NADH ratio
  142. During oxidative-phosphoylation, what reduces oxygen to water?
    Cytochrome C oxidase
  143. How does the number of molecules of ATP produced compare for conversion of one molecule of either glucose or fuctose to pyruvate in a individual whose fructokinase activity is completely absent?
    Fructose and glucose produce the same number of ATPs
  144. In normal mitochondria, the rate of NADH consumption (oxidation) will:
    • Be increased in active muscle, decreased in inactive muscle.
    • Be very low if the ATP synthase is inhibited, but increase when an uncoupler is added
    • decrease if mitochondrial ADP is depleated
    • Decrease when cyanide is used to prevent electron transfer through the cytochrome a+a3 complex
  145. Conversion of 1 mole of acetyl-CoA to 2 mol of CO2 and COA via the citric acid cycle results in the net production of:
    1 mol of FADH2
  146. What is not a characteristic of protein phosphatase 1 (PP1)?
    PP1 is phosphorylated by glycogen synthase kinase (GSK)
  147. Biotin required for?
    oxaloacetate formation
  148. Thiamine required for?
    alpha-ketoglutarate accumulation
  149. Citric acid cycle enzyme is also part of an electron-transport complex
    Succinate dehydrogenase
  150. In alcoholic fermenation, the decarboxylation of pyruvate requires a coenzyme that contains the viatmin
  151. The sequence of glucose oxidation to lactate in peripheral tissues, delivery of lactate to the liver, formation of glucose from lactate in the liver, formation of glycose from lactate in the liver, and delivery of glucose back to peripheral tissues is known as the ___________.
    Cori Cycle
  152. Glycerol-3-phosphate dehydrogenase, the enzyme responsible for the glycerol phosphate shuttle, exists in two isoforms. The cytosolic enzyme uses ________ as conenzyme, whereas the mitochondrial enzyme uses _______ as the coenzyme.
    • NAD+/NADH
    • FAD/FADH2
  153. A lipid-soluble cofactor that can diffuse freely in the membrane of the electron transport chain and carry electrons across the membrane is:
  154. Oxaloacetate uniformly labeled with 14C(i.e., with equal amounts of 14C in each of its four carbon atoms) is condensed with unlabeled acetyl-CoA. After a single pass through the citric acid cycle back to oxaloacetate?
  155. Gulcose 6-phosphatase deficiency
    Does not cause hypoglycemia
  156. The purpose of the pentose phosphate pathway is to
    • synthesize 5-carbon sugar
    • generate NADPH
  157. The hormone ____ induces lipolysis, whereas the hormone ____ inhibits the process.
    Glucagon; insulin
  158. Which do you expect to have the highest protein content by percent?
  159. A female neonate did well until approximately 24 hours age when she became lethargic. Analysis of her blood revealed a drastic elevation af argininosuccinate. Which of the following enzymic activities is most likely to be deficient in this patient?
  160. A ribose sugar is added to _____ rings after thir synthesis and to _____ rings during their synthesis.
    Pyrimidine; purine
  161. The oxidation of 3 mol of glucose by the pentose phosphate pathway with result in the production of:
    3 mol of pentose, 6 mol of NADPH, and 3 mol of CO2
  162. A patient is found to have high concentration of cholesterol in the blood and deposits of cholestrol under the skin. The patient is diagnosed with familial hypercholesterolemia. WHat is the likely cause of this condition?
    Lack of LDL receptors on the surfaces of nonhepatic cells
  163. This amino acid, in high levels, is correlated with the damage of cells lining the blood vessels.
  164. Which is a common precursor in the de novo synthesis of purine nucleotides
    Inosine 5'monophosphate
  165. In pentose phosphate pathway, fragments containing three carbons can be transferred from a ketose phosphate to an aldose phosphate by the enzyme
  166. The beta oxidation of myristyl-CoA (C14:0) yields
    7 Acetyl-CoA + 6FADH2+6NADH+6H+
  167. What is the biologically active form of vitamin D?
    1,25 dihydroxycholechoecalciferol
  168. Which is the correct order for the synthesis of CTP?
  169. Three rounds of Beta-oxidation of palmitate results in ______.
    Three acetyl CoA molecules
  170. The elongation of fatty acids during fatty acid synthesis is repetion of three reactions adding carbons from _____ after each cycle until completion.
    malonyl ACP
  171. SGOT and SGPT are examples of transaminases/aminotrasferases. These enzymes require _______ as coenzymes.
    Pyridoxal phosphate
  172. Carbamoyl phosphate synthetase:
    catalyzes the synthesis of carbamoyl phosphate from bicarbonate (CO2) and ammonia (ammonium ion)
  173. Which sugars are converted into ribulose 5-phosphate by a single enzymatic step?
    • Xyulose 5-phosphate
    • ribose 5-phosphate
  174. The carbon atoms from a fatty acid with an odd number of carbons will enter the citric acid cycle as actyl-CoA and:
  175. List correct steps of Beta oxidation in order
    1. Condensation
    2. Oxidation
    3. Reduction
    4. Thiolysis
    5. Hydration
    6. Phosphorylation
    7. Dehydration
  176. How are fatty acids longer than 16 carbons formed?
    By elongation reaction catalyzed by enzymes on the endoplamic reticulum
  177. What enzyme requires cobalimin (vitamin B12) as a cofactor
    methylmalonyl-CoA mutase
  178. An example of a reaction controlled by enzyme multiplicity is
    phosphorylation of aspartate by aspartokinase
  179. What is true about the structure of cholesterol?
    It contains 27 carbon atoms
  180. What enzymes are needed to break multiple double bonds in a fatty acid in addition to enzymes needed for beta-oxidation
    both enoyl-CoA isomerase and 2,4-dienol-CoA reductase
  181. Transanimation of Oxaloacetate leads to?
    Transanimation of Glutamate leads to?
    • aspartate
    • alpha-ketoglutarate
  182. In erythrocytes the most important function of the HMP shunt is:
    To provide NADPH
  183. Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as:
    Beta-hydroxybutyric acid
  184. What is not required for fatty acid synthesis?
  185. Phenylketonuria (PKU is an amino acid catabolic disease caused by a defect in an enzyme that leads to ______ synthesis
  186. The key regulatory enzyme of pyrimidine biosynthesis is Aspartate transcarbamoylase. Inhibition of ATCase by a _____ nucleotide keeps the balance of purine and pyrimidine pools.
    Pyrimidine (CTP), purine (ATP)
  187. What is true about glutamine?
    • It is a nitrogen donor in many biosynthetic reactions.
    • It is a nitrogen source for glutamate synthase.
    • It carries nitrogen between tissues, thus avoiding high toxic levels of NH4+ in blood
  188. Lipoprotein lipase acts in:
    hydrolysis of triacylglycerols of plasma lipoproteins to supply fatty acids to various tissues
  189. What is true of the biosynthetic pathway for purine nucleotides?
    Inosinate is the purine nucleotide that is the precursor of both adenylate and guanylate
  190. What is not an intermediate in the synthesis of lanosterol from acetyl-CoA?
  191. Fats and fat soluble materials are transported within lipoproteins. Which of the following accurately ranks lipoproteins from highest to lowest density?
  192. Fatty acid biosynthetic pathway needs NADPH as reducing equivalents. A cell that is synthesizing myristic acid, a 14-carbon saturated fatty acid, would use only ______ NADPH molecules from pentose phosphate pathway.
  193. Essential amino acids differ from non-essential amino acids in that:
    non-essential amino acids are synthesized in simple reactions compared to many for most essential amino acids
  194. Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires:
    ATP, carnitine, Coenzyme A
  195. Which sphingolipid is a precursor for all other types of phingolipids?
  196. Allopurinol is effective in the treatment of hyperuricemia because it:
    inhibits xanthine oxidase
  197. If the 16-carbon saturated fatty acid palmitate is oxidized completely to carbon dioxide and water (via the Beat-oxidation pathway and the citric acid cycle), and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion, the net yield of ATP per molecule of acetyl CoA is:
  198. Concerning HMG-CoA reductase, the product of the reaction it catlyzes is acetoacetyl CoA
  199. Ornithine is obtained from?
  200. Alanine is obtained from?
  201. Tyrosine is obtained from?
  202. Glutamine is obtained from
  203. Serine is:
    derived from 3-phosphoglycerate
  204. S-adenosyl methionine is:
    Methyl group donor
  205. Histidine is:
    derived from ribose 5-phosphate
  206. Carbamoul phosphate synthetase I is:
    Required for Urea cycle
  207. Hemolytic anemia is a result of increase in reactive oxygen species. The manifestion of the disease is actually caused by a defect in
    G-6-P dehydrogenase
  208. This intermediate of the urea cycle is hydrolytically cleaved to directly yield urea:
  209. The conversion of ribonucleotides to deoxyribonucleotides is catalyzed by the enzyme
    ribonucliotide reductase
  210. Prostaglandins and thromboxanes are synthesized from ____, a 20-carbon fatty acid.
    arachondoic acid
  211. Glutamate is the precursor for the amino acids glutamine, proline, and ______
  212. Of the two nitrogen of urea, one of the nitrogen atom is obtained from aspartate. In the urea cycle, after a nitrogen atom donation, the carbon skeleton of aspartate is preserved as
  213. Complete the reaction: Acetyl CoA + 7 malonly CoA + 14 NADPH-->
    palmitate + 7CO2 +14 NADP+ + 8 CoA
  214. During transcription the antisense DNA strand is used as a template for mRNA synthesis. If the sequence of the sense strand DNA is 5' ATGGCACTA 3'. What would be the sequence of the mRNA?
    5' AUGGCACUA 3'
  215. What direction does transcription proceed?
    5' --> 3' (correct statement of five given)
  216. What is true concerning rho?
    It has affinity for single-standed RNA
  217. The enzyme photolysase function to
    Repair pyrimidine dimers
  218. Deaminated bases must be removed from DNA because:
    they pair incorrectly during replication
  219. In DNA repair, DNA glycosylases recognize deaminated bases within the DNA polymer and remove the deaminated
  220. RNA polymerase I transcribes genes for:
    18S, 5.8S and 28S rRNA
  221. In the Meselson and Stahl experiment, after two generations of replications in 14N containing culture media, what was the amount of 14N and 15N present in the two bands?
    3/4th 14N and 1/4th 15N
  222. The process of rehybridizing melted DNA is called?
  223. In proteins, amino acids are linked by peptide bonds, in polynucleotides (DNA, RNA) nucleotides link by?
    3'-5' phoshodiester bonds
  224. The tetranucleotide AGTC (in DNA) has a free hydroxyl group on:
  225. In a double stranded DNA, if the total Thymine (T) content is 20%, what percent of guanine is present in the same double stranded DNA?
  226. The "Okazaki Fragments" synthesized during the "leadin stand" replications are processed by DNA olymerase and DNA ligase to give rise to a continuous stand of DNA
  227. DNA polymerase needs a primer to replicate DNA. The primer is an RNA molecule formed by the enzyme_____
    Primase (have to write out!)
  228. The LAC operon is an "inducible operon". This means its usually _____ and directly controlled by _____?
    • Inactive
    • A repressor
  229. The Lac operon is induced when lactose is present as the only carbon source. The real inducer of the operon in the cell is
    Allolactose (have to write out!)