Exam 3 & 4

Arachidonic acid is released from a phospholipid by a specific phospholipase. Without the release of arachidonic acid, which of the following can't be made?
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Arachidonic acid is released from a phospholipid by a specific phospholipase. Without the release of arachidonic acid, which of the following can't be made?
All of the above
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A patient comes into the clinic with severe asthma. Which medications would be the best drug to prescribe, and why? (hint, focus on the enzyme and not the drug)
Zileuton because it will block the 5-lipooxygenase activity
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In a low-energy state, beta-oxidation is utilized to create energy. Fatty acids are metabolized through a series of biochemical steps to produce acetyl CoA. The fate of acetyl CoA after beta-oxidation is for the synthesis of:
Ketone bodies
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The carnitine shuttle is a crucial component of fatty acid beta-oxidation. It utilizes carnitine palmitoyl-transferase I & II (CPT1 & CPTII) to shuttle fatty acyl-CoA into the mitochondria. Which of the following is true concerning the carnitine shuttle?
Malonyl CoA inhibits CPTI
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After eating a meal with many calories where most of those calories are coming from fat, which of the following will occur?
Cholecystokinin (CCK) will be released from cells in the duodenum and act on the gall bladder to release bile into the small intestine.
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Tay-Sachs, Niemann-Pick, and Gaucher's diseases are due to defects in:
enzymes involved in sphingolipid degradation
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The emulsification of lipids in the duodenum is essential in processing dietary lipids. Which of the following is true regarding the emulsification of dietary lipids?
Emulsification increases the surface area of a hydrophobic lipid droplet
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The emulsification of lipids is essential for increasing the surface area of the lipid droplet. Which one of the following is made in the liver and aids in this emulsification?
Bile salts
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It is a new year, and a person is ready to start over and lose weight. For the first time in their life, they have decided to cut back on the calories they take in and work out considerably more. After a 12-hour fast, they go to the gym and do a hard 2-hour workout. A few hours later, they feel muscle soreness and muscle weakness. A few hours later, they have myoglobinuria (rust-colored urine). They see their physician, and it turns out they also have cardiomyopathy. He also tells them they have a deficiency in a specific protein that does not allow them to use fat as a fuel source. Which of the following proteins is most likely the deficient protein?
CPT-II deficiency
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Out of the following choices, what is the best name for this structure (linoleic acid)?
18:2(9,12)
1 MULTIPLE CHOICE OPTION
Patients with hypercholesterolemia (high cholesterol) are often prescribed a class of competitive inhibitors of a specific enzyme in the cholesterol synthesis pathway. What is the type of drugs, and what is the enzyme they inhibit?Statins and HMG CoA ReductaseHigh cytoplasmic citrate levels increase the production of fatty acids by:Stimulating acetyl-CoA carboxylaseWhich of the following molecules inhibits lipases, which prevents TAGs hydrolysis? Therefore, this drug can be used as a mild weight loss mechanism.OrlistatLipid malabsorption can result in loss of dietary lipids in the feces - a condition known as steatorrhea. Several digestive malfunctions can cause this. Which of the following would cause this condition?Cystic FibrosisThe reduction of dihydroxyacetone phosphate (DHAP) to glycerol-3-phosphate (G3P) is performed by the enzyme glycerol-phosphate-dehydrogenase. This enzyme is a significant link between carbohydrate metabolism and lipid metabolism. Which of the following enzymes, located only in the liver, can make glycerol phosphate from a glycerol molecule?Glycerol KinaseThe formation of Malonyl CoA is considered to be the rate-limiting step in fatty acid synthesis. Which of the following enzymes is important for this process?Acetyl CoA carboxylaseThe malic enzyme is an NADP+-dependent malate dehydrogenase in the pentose phosphate pathway (PPP). The PPP can be broken into two functions: to provide ribose 5-phosphate and reduce NADP+ to NADPH/H+. Which of the following functions require NADPH?Fatty acid synthesisPhospholipases are essential for the degradation of phospholipids. They are also involved in cell signaling and present in snake venom and pancreatic juice. Which of the following phospholipases is essential in pancreatic juice, as well as for liberating arachidonic acid from the membrane?Phospholipase A2Plasma-lipoproteins are complexes of lipids and specific proteins, and there are four different types. Each type has a different protein and lipid composition, size, and density. Which lipoprotein contains ApoB-48, Apo E, and Apo C-II?ChylomicronsPlasma-lipoproteins are complexes of lipids and specific proteins, and there are four different types. Each type has a different protein and lipid composition, size, and density. For example, which lipoprotein contains Apo E and Apo C-II and is responsible for returning cholesterol to the liver as cholesteryl esters?High density lipoproteins (HDL)Which lipid molecule is necessary for the synthesis of sphingolipids?CeramideIn steroid-producing tissues, such as the liver, the rate-determining step of synthesizing steroid hormones is catalyzed by a cytochrome P450, "desmolase." The step this enzyme controls is:The conversion of cholesterol to pregnenoloneIn the "well-fed state," which of the following is true?Acetyl CoA is made, and fatty acid synthesis is promotedTriacylglycerols (TAGs) are utilized for energy in many different tissues. Which lipase is essential for the hydrolysis of TAGs in tissues?Lipoprotein lipaseWhy does an infection often result in hemolytic anemia in patients with glucose-6-phosphate dehydrogenase deficiency?Red cells are not able to regenerate sufficient amounts of reduced glutathione (GSH).Which of the following are not one of the four "fates" of glucose which were discussed in class?Synthesis of insulinWhich of the following is an example of a classic second messenger in-cell signaling as it relates to metabolism?cAMP production subsequent to stimulation of a G-protein coupled receptor.Collagen is an important protein component of connective tissues, and there are many diseases that can result from mutations in various collagen genes. Which of the following is true regarding collagen?Type I collagen accounts for over 90% of all collagen in the body.Consider the reaction: A <> B The Go of this reaction in the forward direction (A going to B) is +3.0 kcal/mol. Within a cell, under normal metabolic conditions, this reaction goes in the forward direction. Which of the following is true about this reaction under normal metabolic conditions?The G is negative because [A] is much higher than [B].After multiple people died from taking a new dietary supplement, an investigation occurred. The following is a description that one of the scientists on the forensic team wrote about a compound in the new supplement: "Highly toxic material...Produces marked increase in rate of respiration and body temperature, profuse sweating, collapse, death..."the permeability of the inner mitochondrial membrane to H+.Which of the following is not one of the four "fates" of glucose discussed in class?Synthesis of insulinWhich of the following is true of alpha amylase?It hydrolyzes alpha (1-4) glycosidic bonds between glucose molecules in starch and glycogen.Arsenic poisoning can affect both glycolysis and the TCA cycle. In the TCA cycle, the pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase are affected by trivalent arsenic. What is the common cofactor between these two enzymes that are involved?Lipoic acidATP synthesis occurs in the mitochondrion via a proton-pumping ATP synthase. Which of the following best characterizes this ATP synthase?a multi-subunit protein complex embedded in the inner mitochondrial membraneConsider the reaction: A <> B The delta Go of this reaction in the forward direction (A going to B) is +3.0 kcal/mol. Within a cell, under normal metabolic conditions, this reaction goes in the forward direction. Which of the following is true about this reaction under normal metabolic conditions?The delta G is negative because [A] is much higher than [B].People with essential fructosuria have high levels of fructose, which accumulate in the urine because of a rare autosomal recessive (1:30,000 births) condition. The condition is considered benign. Which of the following enzymes is missing?FructokinaseIf an individual was born with a complete lack of glucose-6-phosphate dehydrogenase enzyme activity, which of the following would best describe their metabolic profile?They would be unable to generate NADPH in red blood cells.Why does an infection often result in hemolytic anemia in patients with glucose-6-phosphate dehydrogenase deficiency?Red cells are not able to regenerate sufficient amounts of reduced glutathione (GSH).In normal healthy individuals, galactose metabolism occurs mainly in the:LiverYou suspect that a newborn infant may have a deficiency of the enzyme galactose 1-phosphate uridylyltransferase (GALT). To provide quick evidence that your suspicion is correct, you would have your lab check the level of (Note: speed is paramount here. Final diagnosis can await further tests.)Galactose in bloodUnder fasting conditions, which of the following would occur in regulating glucose metabolism?Protein kinase A phosphorylates and consequently activates fructose bisphosphatase-2.In a starved state, the liver undergoes a metabolic pathway named gluconeogenesis. The point of this pathway is to produce glucose from pyruvate. One of the earliest steps in this pathway is conducted by an enzyme called pyruvate carboxylase. Pyruvate carboxylase generates oxaloacetate from pyruvate. Which of the following statements is correct about this reaction?Biotin is required.Which of the following generates free glucose (hint, NOT glucose-1-phosphate) during the enzymatic breakdown of glycogen in skeletal muscle?Debranching enzymeGlycogen synthase lengthens a growing chain of glycogen by reacting it with:UDP-GlucoseGlycogen in the liver is used in fasting to provide glucose for use by other tissues, including the brain. Muscle glycogen is not utilized by the rest of the body - only the muscle that stores it. What is the explanation for this difference?Muscle lacks glucose-6-phosphatase.In exercising muscle tissue, when available ATP levels are exhausted, the muscle needs a different source of energy: glycogen. Glycogen phosphorylase b is the enzyme that is activated. What molecule is essential for activating glycogen phosphorylase b?AMPIndividuals with Glycogen Storage Disease Type V (McArdle's disease) have a muscle phosphorylase deficiency. How does the lactate level in their blood after exercise compare with that of an average individual after exercise?DecreasedA three-month-old child is evaluated for failure to thrive. During the examination, the child has a seizure. A blood test indicates severe hypoglycemia, hyperlipidemia, and lactic acidosis. Physical examination is remarkable for hepatomegaly (enlarged liver). Which disease does the patient have, and which corresponding associated enzyme is the issue?Glycogen storage disease Type I (Von Gierke disease), glucose 6-phosphatase deficiencyYou have a neonatal patient near death. You decide to remove fructose from their diet and note an immediate improvement. This patient most likely has a deficiency of at least one form of:Aldolase BI-cell disease is a lysosomal storage disease caused by defective targeting of proteins to the lysosome. The defect causes developmental delay, skeletal defects, and other symptoms that usually result in death by age seven. What is the molecular defect in I-cell disease?Inability to phosphorylate mannose.On a nondescript Tuesday, Julie and her friends decided to get ice cream at The Scoop. Julie had run ten miles earlier in the day and ordered a giant sundae with two huge scoops of ice cream and fresh whipped cream. A few hours later, she had severe bloating and diarrhea after getting home. The following day, she woke up and felt quite dehydrated. Which of the following enzymes is most likely deficient in Julie?LactaseWhich of the following enzymes, or enzyme complexes, not in the TCA cycle would be negatively affected by a deficiency in lipoic acid?Pyruvate dehydrogenasentimycin A, a fish poison and insecticide, inhibits the respiratory chain by binding to the Qi site of cytochrome C reductase (Complex III), inhibiting the transfer of electrons through the electron transport chain. Which of the following is the only possible set of data for isolated mitochondria incubated in the presence of antimycin A and pyruvate? "ATP" = the rate of production of ATP in units of mmoles per minute. "Oxygen" = the oxygen utilization rate in units of atoms per minute. (Remember that one atom of oxygen accepts two electrons.)ATP = 0 Oxygen = 0NADH, made by glycolysis, cannot simply pass into mitochondria for oxidation by the electron transport chain; this is because the inner mitochondrial membrane is impermeable to NADH and NAD+. The cell's solution to this problem is that electrons from NADH, rather than NADH itself, are carried across the mitochondrial membrane. Which of the proposed mechanisms below is the best answer to this problem?Glycerol 3-Phosphate ShuttleIn the presence of insulin, there are high levels of protein phosphatase 1 (PP1) activity. Which of the following statements is true regarding this situation?PP1 inactivates glycogen phosphorylase kinase a by dephosphorylation.Erythrocytes (red blood cells) do not have mitochondria and only use glycolysis to make ATP. Anemia can occur in patients with a deficiency in a specific glycolytic enzyme. Often, this enzyme will have abnormal Km or Vmax for substrates. Which of the following enzymes is most likely the cause of this anemia?Pyruvate KinaseIn a well-fed state where insulin levels are elevated, which of the following is true in the liver?There is a decrease in protein kinase A activity, which leads to fructose bisphophatase-2 inactivity, and an increase of fructose 2,6-bisphosphate.Which of the following is an example of a classic second messenger in-cell signaling as it relates to metabolism?cAMP production subsequent to stimulation of a G-protein coupled receptor.Many tissues, including the lens and retina, have insulin-independent glucose uptake. Hyperglycemia leads to an increased reduction of glucose to sorbitol in these tissues. The sorbitol becomes trapped in the cells and leads to osmotic damage. This is likely an essential contributor to blindness in patients with diabetes. Which enzyme is important for making sorbitol from glucose?Aldose reductaseAfter multiple people died from taking a new dietary supplement, an investigation occurred. The following is a description that one of the scientists on the forensic team wrote about a compound in the new supplement: "Highly toxic material...Produces marked increase in respiration rate and body temperature, profuse sweating, collapse, death..."the permeability of the inner mitochondrial membrane to H+.Collagen is an important protein component of connective tissues, and many diseases can result from mutations in various collagen genes. Which of the following is true regarding collagen?Type I collagen accounts for over 90% of all collagen in the body.Which of the following is true of Transmissible Spongiform Encephalopathies (TSEs)?They are caused by an abnormally folded PrP(Sc) protein.Elastin is a protein that, when cross-linked, gives the tissue a "stretchy" property. It is found in the extracellular spaces of tissues that must routinely expand and contract, such as the lungs. Which of the following is true regarding elastin or elastin-containing tissues?Desmosine cross-links involve four lysine residues, three of them modified by lysyl oxidase.Enzymes can be controlled in many different ways; one particular way, which will change enzyme activity immediately or within a few minutes, is the phosphorylation of an enzyme with a specific kinase. What is the type of regulator event that governs this process?Covalent ModificationThe 7-methyl guanine 'cap' at the 5' end of mRNA is a modification that promotes the following except:translocation of the mRNA to the endoplasmic reticulumThe codon 5'-UAG-3' codes for a cysteine. What is the anticodon? What type of mutation occurs if the codon becomes 5'-UAA-3'?5'-CUA-3'; nonsense mutationDuring DNA replication, the DNA duplex is unwound by helicase, thus generating the replication fork. Beyond the fork, DNA compensates for this unwinding by supercoiling, which is relaxed by the activity of:Topoisomerase