Biochem Exam 3

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  1. blood glucose concentration in the body
    5 mM
  2. grams of glucose in blood
    6 grams
  3. glucose oxidation equation:
    Glucose + 6O2 --> 6CO2 + 6H2O + energy
  4. what is aerobic glycolysis
    oxidative decarboxylation of pyruvate to acetyl CoA
  5. aerobic glycolysis equation:
    Glucose + 2ADP + 2Pi + 2NAD+ --> 2Pyruvate + 2ATP + 2NADH + 2H+ + H2O
  6. net ATP gain of aerobic glycolysis
    2 ATP
  7. molecules of NADH produced per glucose
    2 molecules of NADH
  8. what is anaerobic glycolysis
    pyruvate is reduced to lactate as NADH is oxidized to NAD+
  9. anaerobic glycolysis equation:
    Glucose + 2ADP + 2P --> 2Lactate + 2ATP +2H2O
  10. molecules of ATP generated for each molecule of glucose in anaerobic glycolysis
    2 ATP
  11. net gain/loss of NADH in anaerobic glycolysis
    no net production or consumption
  12. what is reductive biosynthesis
    using reduction to build up something
  13. what is glycolysis followed by
    TCA cycle and electron transport chain
  14. where does the TCA cycle occur
    mitochondrial matrix
  15. where does electron transport chain occur
    inner mitochondrial membrane
  16. what tissues go through anaerobic glycolysis?
    erythrocytes, leukocytes, lens, cornea, medulla of the kidney, testes, ischemic tissues
  17. which produces more ATP, aerobic or anaerobic glycolysis?
    aerobic glycolysis
  18. why do we have inefficient anaerobic process?
    faster, easier, less complicated. may not have the time/resources to go the aerobic route.
  19. what type of fibers do skeletal muscles consists of?
    type I and II fibers
  20. Type I fibers are more aerobic/anaerobic and Type II fibers more aerobic/anaerobic. 
    • type I: more aerobic
    • type II: more anaerobic
  21. Type I fibers are richer/fewer in mitochondria and Type II fibers are richer/fewer in mitochondria.
    • type I: richer in mitochondria
    • type II: fewer in mitochondria
  22. Type I fibers are dominant in muscles associated with _______
    endurance (marathon runners)
  23. Type II fibers are dominant in muscles associated with _________
    rapid movement (sprinters)
  24. Type I fibers are _____ to fatigue. Type II fibers are _____ to fatigue
    • Type I: resistant
    • Type II: easy
  25. Type I fibers are _____ twitch. Type II fibers are _____ twitch.
    • type I: slow (dark meat)
    • type II: fast (white meat)
  26. what are the 2 phases of glycolysis?
    energy investment phase and energy generation phase
  27. what is the energy investment phase?
    phosphorylated forms of intermediates are synthesized at the expense of ATP (breaking down ATP to invest in glycolysis)
  28. The energy investment phase is _____, and the energy generation phase is _____. (endergonic/exergonic) 
    • investment: endergonic
    • generation: exergonic
  29. How much ATP is gained/used in energy investment phase?
    2 ATP are broken down
  30. what is the energy generation phase?
    net of 2 ATPs is formed by substrate-level phosphorylation per glucose molecule metabolized
  31. energy generation phase: _____ ATP are produced and _____ NADH are produced.
    4 ATP, 2 NADH
  32. What are the 3 irreversible/regulatory glycolytic enzymes?
    hexokinase, phosphofructokinase, pyruvate kinase
  33. what enzyme catalyzes the phosphorylation of glucose?
  34. what enzyme catalyzes the isomerization of glucose-6-phosphate to fructose-6-phosphate?
    phosphoglucose isomerase
  35. what are hexokinase and glucokinase?
  36. Hexokinase has product inhibition by _____
  37. Hexokinase has a _____ affinity and a _____ capacity for glucose.
    • high affinity (low Km)
    • low capacity (low Vmax)
  38. What does high affinity of glucose allow?
    efficient phosphorylation and subsequent metabolism of glucose even when concentration is low
  39. what does low capacity allow?
    prevents cell from trapping more sugars than it can use
  40. Glucokinase functions to _____ _____ from the blood.
    remove glucose
  41. Liver channels glucose in _____ _____. Beta cells of pancreas will respond by _____ _____.
    • storage pathways
    • secreting insulin
  42. Glucokinase has a _____ affinity and a _____ capacity for glucose.
    • low affinity (high Km)
    • high capacity (high Vmax)
  43. what does low affinity allow?
    functions only when glucose level is high (right after you eat)
  44. What does high capacity allow?
    allows liver to effectively remove flood of glucose; prevents large amounts of glucose from entering systemic circulation after eating
  45. Hexokinase is found in _____ cells and glucokinase is found in _____ cells.
    • hexokinase: most cells 
    • glucokinase: liver and pancreatic beta cells
  46. Hexokinase is _____ by glucose 6-phosphate. Glucokinase is _____ by glucose 6-phosphate.
    • hexokinase: inhibited
    • glucokinase: not inhibited
  47. Hexokinase is _____ by insulin. 
    Glucokinase is _____ by insulin.
    • hexokinase: not inducible
    • glucokinase: inducible
  48. What happens when you have high glucose levels after a meal (post-prandial)?
    liver glucokinase stores glucose as glycogen
  49. glucokinase is indirectly inhibited by _____ and indirectly stimulated by _____.
    • fructose 6-phosphate
    • glucose
  50. phosphorylation of glucose prevents leakage of _____ from the cell because it is not recognizable by the _____.
    • glucose 6-phosphate
    • GLUT
  51. Why is glucose 6-phosphate not recognizable by the GLUT?
    glucose can leave the cell through the GLUTs. once you add the phosphate, it's more polar and more difficult to leave.
  52. What is GKRP and what does it do?
    • glucokinase regulatory protein
    • regulates activity of glucokinase through reversible binding
  53. What happens to GKRP in presence of fructose 6-phosphate?
    glucokinase is translocated into the nucleus and binds tightly to GKRP, inactivating glucokinase
  54. What happens to GKRP in presence of glucose?
    it will release glucokinase from storage form and make GKRP available for phosphorylating glucose to glucose 6-phosphate
  55. What happens when you no longer need glucokinase?
    it goes back in storage form in the nucleus (GKRP) and is protected there
  56. Mice deficient in GKRP do not respond rapidly to injected glucose. Why?
    absence of a nuclear reserve of glucokinase
  57. What is the most important control point of the energy investment phase?
    fructose 6-phosphate --> fructose 1,6-bisphosphate
  58. What is the enzyme for the reaction: fructose 6-phosphate --> fructose 1,6-bisphosphate?
    • phosphofructokinase-1
    • rate limiting, committed, regulated step
  59. Phosphofructokinase-1 is activated by...
    • AMP 
    • fructose 2,6-bisphosphate
  60. Phosphofructokinase-1 is inhibited by...
    • ATP
    • citrate
  61. Inhibition of phosphofructokinase-1 leads to the accumulation of _____.
    glucose 6-phosphate
  62. What can the accumulation of glucose 6-phosphate be routed towards?
    • gluconeogenesis in liver or kidney
    • glycogen synthesis
    • hexose monophosphate shunt
  63. phosphofructokinase-2 is a _____ enzyme: both a _____ and a _____.
    • bifunctional 
    • phosphatase
    • kinase
  64. Kinase activity of phosphofructokinase-2 produces _____.
    • fructose 2, 6-bisphosphate
    • (adds phosphate to fructose 6-phosphate)
  65. phosphatase activity of phosphofructokinase-2 produces _____.
    • fructose 6-phosphate 
    • (dephosphorylates fructose 2,6 bisphosphate)
  66. Glycolysis is ACTIVATED by:
    • insulin
    • AMP
    • substrate
  67. glycolysis is INHIBITED by:
    • glucagon
    • ATP
    • NADH
    • cyclic AMP
    • Acetyl CoA
    • Citrate
    • product inhibition
  68. What is short term regulation?
    • allosteric activation/inhibition
    • de/phosphorylation of rate-limiting enzymes
  69. What is long term regulation?
    insulin/glucagon induce/repress the transcription of glycolytic enzyme genes
  70. 15-25% of glucose converted to lactate in erythrocytes is shuttled through _____ _____
    BPG shunt
  71. What induces synthesis of 2,3-BPG?
  72. 2,3-BPG is found only in _____?
    red blood cells
  73. What enzyme catalyzes PEP --> pyruvate?
    pyruvate kinase
  74. What is special about pyruvate kinase?
    it REMOVES a phosphate instead of adding one
  75. Pyruvate kinase is activated by:
    fructose 1,6-bisphosphate
  76. Deficiency of _____, _____, and _____ can lead to hemolytic anemia.
    • aldolase
    • triode phosphate isomerase
    • pyruvate kinase
  77. Why are red blood cells more affected by pyruvate kinase deficiency?
    • not a lot of redundancy
    • no nucleus or mitochondria
    • energy in RBC used to fuel pumps that give it biconcave, flexible shape
  78. _____ deficiency in mice appears to be protective against _____.
    • pyruvate
    • malaria
  79. What is the result of phosphofructokinase deficiency?
    • excess glucose 6-phosphate 
    • (fructose 6-phosphate will isomerize)
  80. What is added to blood samples and why?
    • sodium fluoride
    • in order to stop glycolysis
  81. _____ ions inhibit enolase (an enzyme associated with glycolysis).
    fluoride ions
  82. What is the mechanism for arsenic toxicity?
    substitution of phosphorous anion in phosphate, preventing ATP and NADH synthesis.
  83. What enzyme catalyzes pyruvate --> lactate?
    lactate dehydrogenase
  84. What are the 3 pathways for lactate?
    • 1. aerobic: don't make it in the first place 
    • 2. anaerobic: mostly pyruvate --> lactate 
    • 3. don't use lactate locally, diffuses into blood
  85. Pyruvate --> Lactate serves to oxidize _____ to _____.
    NADH to NAD+, providing more NAD+ for continued anaerobic glycolysis
  86. What is the final product of anaerobic glycolysis in eukaryotic cells?
  87. Which tissues derive their energy from anaerobic glycolysis?
    erythrocytes, skeletal muscles in state of exertion, lens and cornea of the eye, testes, leukocytes, and kidney medulla.
  88. Lactate can be used by the ______ to generate glucose.
  89. Lactate can be used by the _____ or _____ to regenerate pyruvate.
    heart or kidney
  90. heart exclusively oxidizes _____ to _____ and _____ via the citric acid cycle.
    lactate to CO2 and H2O
  91. in liver and heart, the ratio of NADH/NAD+ is _____ than in exercising muscle.
  92. What is responsible for most of the muscle soreness felt on days following physical exertion?
    tears in the muscle NOT lactate
  93. What are the 3 processes of glucose oxidation?
    • 1. glycolysis
    • 2. TCA cycle
    • 3. electron transport chain
  94. These conditions raise the NADH/NAD+ ratio and promote the formation of lactate:
    • 1. CO poisoning
    • 2. sickling crisis
    • 3. ischemic tissue
    • 4. myocardial infarction
    • 5. mitochondrial disease
    • 6. warburg effect
    • 7. alcohol intoxication
  95. What is the Warburg effect?
    most cancer cells are anaerobic
  96. Alcohol intoxication is the _____ leading risk factor for death/disability.
  97. Alcohol intoxication can lead to _____ _____ .
    liver cirrhosis
  98. The oxidation of alcohol results in significant amounts of _____ in the liver.
  99. What is another way of metabolizing ethanol?
    it will be metabolized as a xenobiotic and associated with CYPs
  100. What does MEOS stand for?
    microsomal ethanol oxidizing system
  101. Citric Acid Is Kreb's Starting Substrate For Mitochondrial Oxidation
    Citrate Aconitrate Isocitrate alpha-Ketoglutarate Succinyl CoA Succinate Fumarate Malate Oxaloacetate
  102. What happens in the TCA cycle?
    oxidation of carbs, proteins, and lipids
  103. What other processes can the TCA cycle participate in?
    transamination, deamination, lipogenesis, gluconeogenesis
  104. TCA cycle produces reduced co-enzymes _____ and _____
    NADH and FADH2
  105. _____ genetic defects are associated with the TCA cycle.
  106. What kind of metabolism is the TCA cycle?
    Amphibolic, both anabolic and catabolic
  107. Where are the TCA enzymes located?
    mitochondrial matrix
  108. What enzyme catalyzes pyruvate --> acetyl CoA?
    pyruvate dehydrogenase complex
  109. What 5 specific nutrients does the pyruvate dehydrogenase complex require?
    thiamine, pantothenic acid, niacin, riboflavin, and lipoid acid
  110. Pyruvate Dehydrogenase Complex is ACTIVATED by:
  111. Pyruvate Dehydrogenase Complex is INHIBITED by:
    acetyl CoA, NADH, and ATP
  112. phosphorylating PDH _____ it. 
    dephosphorylating PDH _____ it.
    • inactivates
    • activates
  113. Energy production of TCA cycle:
    • 3 NADH --> 3 NAD+ : 3 ATP per (9)
    • FADH2 --> FAD : 2 ATP per (2)
    • GDP --> GTP : 1 ATP per (1)

    12 ATP total
  114. TCA cycle is INHIBITED by:
    • ATP
    • NADH
    • FADH2
  115. What does the TCA cycle generate?
    • 3 NADH
    • 1 FADH2
    • 1GTP
  116. What is oxidative phosphorylation the opposite of?
    substrate level phosphorylation
  117. How is the inner mitochondrial membrane arranged?
    arranged in cristae
  118. What is the purpose of the cristae in the inner mitochondrial membrane?
    increases the surface area
  119. The enzymes associated with oxidative phosphorylation and electron transport are located in the _____.
    inner mitochondrial membrane
  120. Inner membrane is highly _____ to small ions, small and large molecules.
  121. Outer membrane is highly _____ to small ions, small and large molecules.
  122. The space between the inner and outer membrane is called the _____.
    intermembrane space.
  123. What does the mitochondrial matrix contain?
    TCA cycle enzymes, fatty acid oxidation enzymes, mtDNA, mtRNA, and mitochondrial ribosomes
  124. Electron transport chain uses electrons in such a way that you can generate _____.
  125. ETC shuttles electrons around to reduce _____ and eventually end up making _____.
    • reduce oxygen
    • make water
  126. mitochondrial metabolic water
    makes less than 10% of the amount we need
  127. As you move forward in the ETC, there is a _____ affinity for the electron until you reach O2.
    higher affinity
  128. What is the free energy change in the ETC utilized for?
    to pump H+s from the matrix into the intermembrane space
  129. How can the electrons in oxidative phosphorylation be transferred?
    as lone electrons, hydrogen atoms, or hydride ions.
  130. What does the free energy change in ETC result in?
    electrochemical gradient
  131. Energy released from electrochemical gradient will be harnessed to make _____.
  132. Why doesn't the ETC make as much ATP as it could?
    • losses from inefficiency
    • complexes use energy
  133. How is the electrochemical differential is resolved and where does it occur?
    • by the H+s entering into the mitochondrial matrix
    • point of entry is complex V
  134. What is the chemiosmotic theory?
    proton motive force; free energy generated by ETC is used to produce ATP
  135. Where is ATP synthase located?
    Complex V
  136. What is the ultimate acceptor of electrons in ETC?
  137. How many molecules of H2O are produced for each molecule of both FADH2 and NADH?
    1 molecule of water
  138. What enzyme catalyzes the synthesis of water and where is it located?
    cytochrome oxidase on complex IV
  139. What is the electron transport chain composed of?
    3-5 protein complexes and two mobile carriers
  140. What type of proteins are the complexes in ETC?
    integral inner mitochondrial membrane proteins
  141. What are the two mobile carriers in ETC?
    coenzyme Q (ubiquinone) and cytochrome c
  142. What kind of molecule is coenzyme Q (ubiquinone)?
    derivative of quinone, NOT a protein
  143. Coenzyme Q (ubiquinone) possesses _____.
    significant anti-oxidative capabilities
  144. ETC proteins may contain _____ or _____.
    iron-sulfur or copper
  145. What is special about ETC cytochromes?
    can switch back between ferrous and ferric states (unlike hemoglobin)
  146. ETC proteins may be _____ or _____.
    flavoproteins or cytochromes
  147. ETC proteins may possess _____.
    enzymatic ability
  148. Oxidative phosphorylation of the ETC complements _____.
    substrate level phosphorylation
  149. What is a P:O ratio?
    number of moles of ATP synthesized relative to the number of moles of O2 consumed
  150. What is the P:O ratio of NADH?
  151. What is the P:O ratio of FADH2?
  152. What is the approximate energy yield from aerobic respiration?
    • 38 ATP 
    • (8 from glycolysis, 6 from pyruvate dehydrogenase, and 24 from TCA cycle)
  153. What is the free energy of hydrolysis of an ATP?
    7.3 kcal/mole
  154. What is the efficiency of ATP synthesis?
    39.4% efficiency of ATP synthesis
  155. What is the function of site-specific inhibitors?
    prevent the passage of electrons in the ETC
  156. What are examples of site-specific inhibitors?
    rotenone, amytal, antimycin, sodium azide, cyanide, carbon monoxide
  157. Rotenone is a _____ and _____.
    insecticide and piscicide
  158. Amytal is a _____.
    barbiturate (sedative)
  159. Antimycin is a _____.
  160. Sodium azide (N3) is used as a _____.
    chemical preservative
  161. Cyanide and carbon monoxide bind to _____ to prevent the last step.
    cytochrome oxidase
  162. Oligomycin binds to a specific domain of _____ and blocks the H+ channel.
    ATP synthase
  163. What is the function of oligomycin?
    transport of electrons into the mitochondrial matrix.
  164. What do uncoupling proteins create and what does that allow?
    proton leak, allows protons to reenter the mitochondrial matrix without capturing energy as ATP
  165. What is the energy from the proton leak used for?
    heat production, NOT ATP production
  166. What molecules possess uncoupling capacity?
    • bilirubin
    • thyroxine
    • ionophores
  167. Uncoupling occurs naturally in ______.
    brown adipose tissue
  168. Why is brown adipose tissue brown?
    rich in mitochondria
  169. What is thermogenin?
    an uncoupling protein found in brown adipose tissue good for generating heat.
  170. What does thermogenin do?
    increases the permeability of the inner membrane to H+ ions
  171. Why do newborn babies have brown adipose tissue?
    • they can't shiver
    • can't feed themselves
    • higher ratio of surface to volume
    • larger heads so heat escapes
    • little body hair
    • no effective blood vessel constriction
  172. What is the cause of mitochondrial disorders?
  173. What kind of tissues are mitochondrial disorders associated with? What are examples?
    tissues that require critical levels of operant energy, examples: muscular or nervous system
  174. Do you have mitochondria in every cell of your body, and can they vary?
    • no
    • yes
  175. Who do you get mitochondria from?
    • mother
    • sperm does not deliver mitochondria
  176. The mitochondrial genome consists of _____ base pairs?
    16.5 thousand base pairs
  177. What shape is the mitochondrial genome?
  178. The mitochondrial genome codes for _____ genes.
    37 genes
  179. Is the mitochondrial genetic code identical to other organisms?
    No, genetic code isn't universal
  180. 90% of proteins associated with oxidative phosphorylation are encoded in the cell _____ and imported into the _____.
    • nucleus
    • mitochondria
  181. _____ and _____ are variable for the mitochondria.
    number and shape
  182. Rate of mutation in _____ genome is approximately 10x greater than _____ genome.
    mitochondrial genome > nuclear genome
  183. How are mitochondrial disorders inherited?
    maternal, autosomal dominant/recessive, and sec-linked dominant/recessive
  184. Mitochondrial _____ is released in response to cell death stimulus.
    cytochrome c
  185. Release of mitochondrial cytochrome c leads to formation of the _____.
  186. What is an apoptosome?
    large protein complex
  187. The apoptosome is involved in the initiation of the _____ _____.
    caspar cascade
  188. Fasting or vigorous exercise ______ the amount of blood glucose.
  189. What is gluconeogenesis?
    synthesis of new glucose
  190. What is glycogenolysis?
    breakdown of glycogen to individual glucose molecules
  191. What 5 tissues are glucose essential for?
    • brain
    • erythrocytes
    • adipose tissue
    • skeletal muscle
    • mammary gland
  192. What happens in the Cori Cycle?
    • Muscle anaerobically makes lactate
    • lactate goes through blood to liver
    • lactate makes glucose in liver 
    • glucose is released into blood
    • glucose taken up by muscle
  193. _____ is oxidized to _____ in the mitochondria in glycolysis.
    NADH oxidized to NAD+
  194. In the absence of oxygen, _____ is regenerated by the formation of _____.
    • NAD+
    • lactate
  195. Pyruvate -----> Lactate is catalyzed by _____.
    pyruvate dehydrogenase
  196. What are 3 carbon sources for gluconeogenesis?
    • 1. glycerol released from adipose lipolysis
    • 2. muscle lactate
    • 3. glycogenic amino acids
  197. Why does muscle not engage in gluconeogenesis?
    • missing the essential enzyme glucose 6-phosphatase
    • muscle lactate is transported to the liver
  198. What amino acid can be used as a source of carbon for gluconeogenesis?
    alanine (glucose--alanine cycle)
  199. Where does gluconeogenesis occur?
    primarily in the liver
  200. Where are gluconeogenesis enzyme located?
    primarily in the cytosol
  201. What is glucose 6-phosphatase bound to?
    smooth ER
  202. Where is pyruvate carboxylase located?
    mitochondrial matrix
  203. How many reactions are bypassed by gluconeogenesis and why?
    • 3 irreversible reactions
    • large negative change in free energy
  204. Gluconeogenesis: CO2 is activated and transferred by _____ to its biotin prosthetic group.
    pyruvate carboxylase
  205. Pyruvate carboxylase transfers CO2 to pyruvate, generating _____.
  206. _____ cannot cross the mitochondrial membrane, so it is reduced to _____.
    • oxaloacetate
    • malate
  207. In the _____, malate is re-oxidized to oxaaloacetate.
  208. In the cytosol, oxaloacetate is converted to _____ by _____.
    • phosphoenolpyruvate (PEP
    • PEP carboxykinase
  209. In humans, PEP carboxykinase is located in both the _____ and the _____, but only the _____ enzyme participates in gluconeogenesis.
    • cytosol
    • mitochondria
    • cytosolic
  210. What enzyme catalyzes fructose 1,6-bisphosphate --> fructose 6-phosphate?
    fructose 1,6-bisphosphatase
  211. _____ inhibits fructose 1,6-bisphosphatase, therefore inhibiting gluconeogenesis.
    fructose 2,6-bisphosphate
  212. High glucagon/insulin ratio causes elevated _____ and increased _____.
    • cAMP
    • protein kinase A
  213. Increased protein kinase A favors _____ form of PFK-2/FBP-2 complex.
  214. phosphorylated PFK-2 is _____ which impedes formation of _____.
    • inactive 
    • fructose 2,6-bisphosphate
  215. decreased levels of fructose 2,6-bisphosphate decreases the inhibition of _____, which increases _____.
    • fructose bisphosphate phosphatase-1
    • gluconeogenesis
  216. High insulin/glucagon ratio causes _____ cAMP and ______ protein kinase A.
    • decreased
    • reduced
  217. Decreased protein kinase A favors _____ form of PFK-2/FBP-2 complex.
  218. dephosphorylated PFK-2 is _____ which favors formation of _____.
    • active
    • fructose 2,6-bisphosphate
  219. increased levels of fructose 2,6-bisphosphate activates _____, which increases _____.
    • phosphofructokinase-1
    • glycolysis
  220. What enzyme catalyzes glucose 6-phosphate --> D-glucose?
    glucose 6-phosphatase
  221. glucose 6-phoshate is translocated to the ER membrane by _____.
    glucose 6-phosphate translocase
  222. Gluconeogenesis is ACTIVATED by:
    • glucagon
    • elevated levels of gluconeogenesis precursors 
    • acetyl CoA
  223. Gluconeogenesis is INHIBITED by:
    • insulin
    • AMP
  224. What is glycogen?
    highly branched polymer (dendrimer) of glucose
  225. What does the presence of branches on glycogen provide?
    more opportunities for rapid degradation and synthesis
  226. Liver glycogen tends to _____ while muscle glycogen tends to _____.
    • liver: fluctuate more
    • muscle: be more stable
  227. Glycogenolysis is more _____ while gluconeogenesis is more _____.
    • rapid
    • sustained
  228. What is the function of glycogenesis and glycogenolysis in the liver?
    maintenance of blood glucose levels during early portions of fast and during exercise
  229. What is the function of glycogenesis and glycogenolysis in the muscle?
    provision of fuel to be used by the muscle during exercise
  230. What are 2 major hormones that regulate glycolysis and gluconeogenesis?
    insulin and glucagon
  231. Insulin is more _____ and glucagon is more _____. (anabolic v catabolic)
    • anabolic
    • catabolic
  232. Every _____ glucosyl residues there is a branch.
  233. What kind of branch point is found in glycogen?
    alpha (1->6) linkage
  234. Glycogen is stored in both muscle and liver in ______.
  235. Where are the enzymes associated with synthesis and degradation localized?
    in the muscle and liver granules.
  236. Glucose 6-phosphate is isomerization with _____.
    glucose 1-phosphate
  237. _____ serves as the primer for glycogen synthesis. what is it attached to?
    • glycogenic
    • tyrosine
  238. What enzyme extends the alpha 1,4 linkages on the nonreducing ends?
    glycogen synthase
  239. _____ adds alpha 1,6 bonds to glycogen.
    branching enzyme
  240. What is the rate limiting factor in glycogen synthesis?
    glycogen synthase
  241. What enzyme catalyzes glucose --> glucose 1-phosphate?
    glycogen phosphorylase
  242. What kind of enzyme is glycogen phosphorylase?
    hydrolytic enzyme
  243. Glycogen phosphorylase requires coenzyme _____.
    pyridoxal phosphate (vitamin B6)
  244. Glycogen phosphorylase is a _____ enzyme, meaning it moves one a at a time.
  245. What is the rate limiting factor in glycogenolysis?
    glycogen phosphorylase
  246. epinephrine and norepinephrine stimulate _____ and _____ by binding to alpha and beta adrenergic receptors.
    • synthesis of cAMP
    • elevation of intracellular calcium
  247. cAMP functions in a synergistic manner w/ _____ to regulate glycogen metabolism.
  248. Does glucagon have more of an effect on muscle or liver?
  249. _____ and _____activates G proteins, _____ does not.
    • glucagon and epinephrine
    • insulin
  250. _____ activate protein phosphatase-1 to remove P from glycogen phosphorylase kinase a
  251. what is the role of calcium in muscle?
    binds to calmodulin subunit to activate phosphorylase kinase
  252. what is the role of AMP in muscle?
    activates glycogen phosphorylase b
  253. What ACTIVATES glycogen breakdown in liver?
    • glucose
    • ATP
    • glucose 6-phosphate
  254. What INHIBITS glycogen breakdown in liver?
    glucose 6-phosphate
  255. What ACTIVATES glycogen breakdown in muscle?
    • calcium
    • AMP
    • glucose 6-phosphate
  256. What INHIBITS glycogen breakdown in muscle?
    • glucose 6-phosphate 
    • ATP
  257. What are the functions of calmodulin?
    • nerve growth
    • muscle contraction
    • inflammation
    • apoptosis
    • intracellular movement
    • immune processes
  258. Where does calmodulin function?
    inside different organelles
  259. calmodulin: calcium is released from ______ in response to hormones or neurotransmitters.
    endoplasmic reticulum
  260. Increase of intracellular Ca2+ favors formation of _____.
    calmodulin-Ca2+ complex
  261. _____% of the calories ingested are fat, while the maximal percentage of fat in the optimal diet is _____%.
    • 38%
    • 30%
  262. What are the functions of fat/lipids?
    • energy storage
    • transport/utilization of fat-soluble vitamins
    • essential fatty acids
    • insulation against heat loss
    • insulation against trauma
    • insulation against water loss 
    • brain structure and nervous function
    • hormones
    • cell membranes
    • mother's milk
  263. What are the fat-soluble vitamins?
    A, D, E, K
  264. What are the representative lipids?
    fatty acids, triacylglycerol, phospholipid, steroid, glycolipid
  265. What is the predominant lipid in our diet?
  266. _____ and _____ lipase hydrolyze short/medium chain TAGs
    lingual and salivary
  267. What is a short/medium chain TAG?
    4-12 carbons
  268. Where are bile salts made and where are they stored?
    • MADE in liver
    • STORED in gall bladder
  269. What is the function of bile salts?
    emulsify fats
  270. Emulsify fat:
    • help fat interact with water soluble environment 
    • make globular fat smaller
  271. _____ and _____ are recreated from the pancreas.
    pancreatic lipase and colipase
  272. What does pancreatic lipase do?
    hydrolyzes TAGs to 2-monoacylglycerols
  273. Why do you need a supporting enzyme (collapse)?
    bile interferes with lipase so you need collapse to help get the job done
  274. What is the structure of a bile salt micelle?
    hydrophobic inside, hydrophilic outside (easier to interact with water)
  275. What do micelles contain?
    TAGs, undigested monoacylglycerides, fatty acids, fat soluble vitamins
  276. Micelle contents are absorbed into _____.
    intestinal mucosal cells (enterocytes).
  277. _____ are reformed in intestinal mucosal cells and _____ are assembled.
    • TAGs
    • chylomicrons
  278. What do chylomicrons consist of?
    TAGs, cholesteryl esterified to free fatty acid, apoprotein, and phospholipids
  279. Where are chylomicrons found?
    endoplasmic reticulum
  280. _____ are not incorporated into chylomicrons.
    short/medium chain fatty acids
  281. Where are short/medium chain fatty acids released?
    portal circulation
  282. What transports short/medium chain fatty acids into portal circulation?
    serum albumin
  283. How are chylomicrons released?
    exocytosis into lymphatic vessels (lacteals)
  284. What is chyle?
    milky-colored fluid in lacteals
  285. TAGs in chylomicrons are hydrolyzed by _____/
    lipoprotein lipase
  286. TAGs are hydrolyzed by lipoprotein lipase in _____ and _____?
    in skeletal muscle and adipose tissue capillaries
  287. What can free fatty acids do?
    • oxidized for energy
    • transported with serum albumin to other cells
    • re-esterified in adipose cells and in liver to TAGS
  288. chylomicron remnants enter liver through _____ and are hydrolyzed.
  289. What are 2 regulatory intestinal hormones?
    secretin and cholecystokinin
  290. What is secretin stimulated by?
  291. Secretin stimulates the release of _____ from liver and pancreas.
    water bicarbonate solution
  292. What is the purpose of the bicarbonate solution?
    neutralize stomach acid
  293. Cholecystokinin stimulates pancreas to secrete _____.
    digestive enzymes
  294. Cholecystokinin stimulates the gallbladder to _____ and the stomach to reduce its _____.
    • contract
    • gastric motility
  295. lingual and gastric/salivary lipase are most active during _____.
    early childhood
  296. where do pancreatic lipase hydrolyze fatty acids?
    from positions 1 and 3
  297. _____ enhances pancreatic lipase.
  298. what enzyme catalyzes cholesterol ester --> cholesterol?
    cholesterol esterase
  299. _____ liberates a fatty acid from a phospholipid.
    phospholipase A2
  300. Cholic acid can be covalently attached to either a molecule of _____ or _____.
    glycine or taurine
  301. which is more hydrophilic, taurine-conjugated chalice acid or glycine-conjugated chalice acid?
    taurine-conjugated chalice acid
  302. what is taurine?
    an amino acid-like structure
  303. What does bile consist of?
    • water
    • cholesterol
    • bilins
    • bile acids/bile salts
    • phospholipids
    • bicarbonate and other ions

Card Set Information

Biochem Exam 3
2017-11-12 06:29:49

glycolysis, gluconeogenesis, TCA cycle, glycogenolysis, lipids
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