Molecular Biology and Biochemistry of Glucose and Lipid Metabolism, Exams of Biochemistry

Download Molecular Biology and Biochemistry of Glucose and Lipid Metabolism and more Exams Biochemistry in PDF only on Docsity! 1 / 13 Biochem Exam 5 Questions with Answers Tested and Verified Correct Updates 1.Trimethoprim: Which of the following drug will be more appropriate for urinary tract infection? Azaserine. Allopurinol Fluorouracil Methotrexa te Trimethopri m. 2.Telomeres: Which of the following routinely change base-pair length with DNA replication, but without having an effect on DNA coding? plasmids telomeres introns transposo ns highly repetitive sequences 3.Folate analog. It is an immunosuppressant.: What type of analog is methotrex- ate? 4.Both have cell proliferation: What is the similarity between cancer and 2 / 13 inflam- mation? 5.Because of different gene expression: If we have the same DNA, why do we look different? 6.Cistron: A section of DNA or RNA molecule that codes for a specific polypeptide in protein synthesis? 7.Genes: Segments of DNA that code for peptides and RNAs = 8.Differential splicing of RNA: How can one gene give different products? 9.DNA to RNA to protein: What is the order of the central dogma? 10.Viruses that have reverse transcriptase: What is an exception to the central dogma? 11.codon degeneracy: What is it called when 1 amino acid is coded by multiple codons? 12.Histones: What serves to neutralize negatively charged DNA? 13.Comes from mother; for energy production and inheritance;: What are the significances of mtDNA? 14.Yes: Do mitochondria perform oxidative phosphorylation? 15.True: T/F Number of genes do not correlate with complexity. 16.1.5 % (exons): What percent of the total genome encodes for proteins? 17.Exons Centromeres Telomeres: Non-repetitive sequences = Moderately repetitive sequences = Highly repetitive sequences = 18.Transposons: These can move around within the genome of a single 5 / 13 between metabolic syndrome and metabolic disorder? 41.Get tired easily, hyperglycemia, hyperlipidemia, increased blood pressure, obesity: What are some symptoms of metabolic syndrome? 42.Syndrome in which metabolites are not in balance.: What is metabolic syn- drome? 43.To keep oxidizing things to extract energy.: Why do we breathe oxygen as opposed to other gases? 44.Dynamic: Organisms try to maintain homeostasis and stay at equilibrium. What type of equilibrium is this? (Static or dynamic) 45. 55000 glucose/beta particle Each rosette has 20-40 beta particles: How many glucose molecules are there per beta particle? 46. 8-10% Muscle is 1-2%: What percent w/w of the liver is glycogen granules? 47.Liver and muscle: Glycogen storage diseases primarily affect: 48.Liver: Type Ia GSD (Von Gierke) affects the . 49.12 tiers: How many tiers are there in a mature glycogen particle? 50.Glycogenin: Rosette formation initiates at . 51.Alpha 1-4 are between glucose molecules in a chain. Alpha 1-6 are the bonds where the glucose chains branch.: Where are alpha 1-4 and alpha 1-6 bonds in a rosette? 52.Glycogen phosphorylase (removes glucose one at a time) Debranching enzymes (transferase activity transfers 3 residues from branch to chain; glucosidase removes the one branched glucose): Which 2 enzymes catalyze glycogenolysis? 6 / 13 53.E. Muscle cells have the receptors for epinephrine while liver cells don't.- : Which of the following is NOT CORRECT about the major differences between muscle and liver in terms of glucose regulation? A. Muscle uses stored glycogen only for its own needs while liver doesn't B.During exercise, muscle undergoes very large changes in need of ATP compared to liver C. Muscle lacks the enzyme machinery for gluconeogenesis while liver doesn't. D.Muscle cells lack a receptor for glucagon while liver cells don't (lack). E. Muscle cells have the receptors for epinephrine while liver cells don't. 54.B. Phosphoglucomutase: Glycogenolysis releases a form of glucose that can- not enter glycolysis. What enzyme acts as gatekeeper to transform it into a glycolytic intermediate? A. glycogen phosphorylase B.phosphoglucomutase C. NDP-sugar pyrophosphorylase D.glycogenin 55.Phosphoglucomutase: What converts G-1-P to G-6-P? 56.UDP-glucose: Glucose is converted into before becoming glyco- gen through glycogen synthase. 57.B. Liver: Where are glucagon receptors located? A. Muscle B.Liver C. Both 7 / 13 D.Neither 58.Epinephrine: What hormone in muscles signals glucose to be created? 59.Glycogen: Insulin activates glycogen synthase which increases synthesis. 60.Dephosphorylated: Is the active form of glycogen synthase phosphorylated or dephosphorylated? 61.Liver and muscle: Epinephrine receptors are found in: 62.NO: Are muscles able to perform gluconeogenesis? 63.G-6-P to glucose Hexokinase does the opposite.: Glucose 6-phosphatase converts to . 64.Glucose 6-phosphatase This leads to a buildup of glycogen in the liver causing an enlarged liver. It can also lead to an enlarged kidney.: In Von Gierkes disease, the patient has a defective . 65.Provide frequent source of dietary glucose and starch.: What is the treat- ment for Von Gierkes disease? 10 / (E)Von Gierke disease 75.Albumin: Free fatty acids are transported in the blood by binding to which of the following? Hemoglobin Gamma globulins Albumin Platelets 76.LDH1/LDH2 ratio. Right after heart attack, LDH 2 is larger. Then they be- come equal. And lastly LDH 1 is larger. This switch along with creative kinase concentration in blood is strong evi- dence of a heart attack.: From Reading: LDH (lactate dehydrogenase) was one of the first enzymes found to have isozymes. When a MI has occurred the ratio change of which 2 LDH enzymes show strong evidence of a MI? 77.Isozymes: Enzymes that catalyze the same reaction but may be coded by different genes = 78.4: How many human Hexokinase isozymes are there? 79.Located in muscle and have high affinity: Hexokinase I and II are located in the . These have a affinity for their substrate since their Km = 0.1mM. Because of this, they can operate at near maximum rate in blood glucose level 1mM to 5mM. 80.Liver and pancreas; 10mM; high: Hexokinase IV is located in the and has a Km of . This means it only runs when blood glucose levels are such as after a high carb meal. 11 / 81.Hexokinase II (Km=0.1mM): Is Hexokinase kinase II or IV faster at a glucose concentration of 4mM. 82.It is bound tightly to a regulator protein which keeps it inside the nucleus so it is not active. This happens in lower glucose.: Hexokinase IV is subject to regulation by the allosteric effect of glucose and fructose 6-P. If F-6-P wins this battle, what happens to Hexokinase IV? 83.It gets detached from its regulator protein and comes into the cytosol where it can convert glucose into G-6-P and lower the level of glucose.: What happens to Hexokinase IV during high glucose levels after a meal? 84.AMP. This is the key to losing weight.: Cells are 100 times more sensitive to change in than ATP. 85.Fat and carbohydrate: Elevated AMP activates AMP-activated protein kinase (AMPK) which regulates and metabolism. 86.All the above: What can increase AMPK? A. increase AMP B.Decrease ATP C. Exercise D.Leptin E. Hypothalamus 87.AMPK: What is a supplement taken to increase weight loss by activating the body to use more fat? 88.Fructose-2,6-bisphosphate (F-2,6-BP) Why? Cause PFK-1(phosphofructokinase-1) is inactive in the absence of F-2,6-BP *this is also the commitment step in glycolysis*: Glycolysis will not proceed 12 / unless this non-glycolysis metabolite is present to lower the Km. 89.Raises. F-2,6-BP or AMP has opposite effects on Km.: ATP allosterically the Km for PFK1 and F-6-P. 90.Pyruvate kinase Gluconeogenesis is then stimulated.: What enzymes is inactivated by phospho- rylation in response to signs of glucose depletion (glucagon) in the liver? 91.Glycolysis; Gluconeogenesis: AMP stimulates and inhibits . 92.It inhibits glycolysis. GDP activates glycolysis.: What effect does high ATP have on glycolysis? 93.Alpha cells: What cells of pancreas secrete glucagon? 94.Adrenal gland: What stimulates epinephrine? 95.Degradation cause energy is needed so glucose is needed: Glucagon and epinephrine stimulate glycogen . Synthesis or degradation 96.The positron emitter F18 that is produced during glucose consumption. An excess in glucose consumptions leads to high levels which can be seen by the scans.: One way to determine if cancer has metastasized is by using an overlay of CT and PET scans. What do these scans detect that shows where the cancer has spread to? 97.Sepsis (normal lactate range is 1mmol/L): What does elevated lactate signi- fy? 98.No. Fatty acids become Acetyl CoA which cannot enter gluconeogenesis.- 15 / 114. Citrate lyase: What enzyme turns citrate back to Acetyl-CoA once it is outside the mitochondria? 115. True: T/F Most Acetyl-CoA comes from pyruvate oxidation (after glycolysis), and most NADPH comes from the pentose phosphate pathways and malic enzyme in adiopocytes, hepatocytes, and mammary gland (only PPP). 116. NADPH and Acetyl-CoA: What is needed for fatty acid synthesis? 117. It increase fatty acids synthesis and decreases beta-oxidation (fat break- down). Ethanol also causes more NADH to be produced which causes more ATP which leads to more FA synthesis.: How does alcohol consumption make you accumulate body fat? 118. They trigger phosphorylation which causes inactivation of Acetyl CoA to malonyl CoA.: What effect do epinephrine and glucagon have on fatty acid synthesis? 119. Eicosanoids: Polyunsaturated fatty acids (PUFAs) are precursors to . 120. Membrane fluidity: PUFAs are also important because the help control . 121. prostaglan dins leukotrienes thromboxanes: Eicosanoid hormones include: 122. a rachidonate for both: Eicosanoids are made from 16 / present in phospholipids of membranes. They are made in response to stimuli. Phos- pholipase A2 is activated and attacks the C-2 fatty acid releasing . 123. phospholipase A2: Steroids like prednisolone or prednisone inhibit what? 124. Oxidases do not incorporate oxygen into the product. Oxygenases do incorporate oxygen into the product.: What is the main differ- ence between oxidases and oxygenases? 125. slow acting: Are steroids fast acting or slow acting during arachidonic acid biosynthesis? 126. leukotrienes: Which eicosanoid can cause asthma attacks? 127. thromboxanes: Eicosanoid that can increase blood clotting ability of platelets and cause vasoconstriction? 128. They block thromboxanes which means platelets do not clot as easily and blood vessels do not constrict. This means less risk of heart attack or stroke. Low dose so gastric ulcers don't form.: Low dose aspirin can reduce cardiovas- cular problems because: Why low dose? 129. prostaglandins and thromboxanes *NSAIDs inhibit COX: NSAIDs inhibit which 2 eicosanoids while steroids inhibit all? 130. leukotrienes: Montelukast inhibits formation. 17 / 131. gastric ulcer: Prostaglandin H2 synthase (PGH2) has 2 isoforms, COX1 and COX2. Blocking COX 1 using aspirin or an NSAID can lead to because gastric mucus secretion is lessened. 132. irreversible So NSAIDs are safer cause they are competitive.: Aspirin is an inhibitor while ibuprofen and naproxen are competitive inhibitors. 133. Celecoxib (Celebrex): What NSAID is a COX-2 specific inhibitor so the stom- ach is not harmed? 134. mevalonate This is formed by HMG-CoA reductase.: Formation of is the commit- ment step in cholesterol synthesis. This means it is a regulatory step (far from eq). 135. They inhibit HMG-CoA reductase which stops the formation of meval- onate which is what leads to cholesterol synthesis.: What is the biochemical basis of statin drugs function? 136. condensation, conversion, condensation, cyclization: What are the 4 C's of cholesterol biosynthesis? 137. chylomicron: What transfers dietary fats from intestines to the liver? 138. chylomicrons: How are dietary fats mobilized in the body? 139. liver and adipose tissue: What are the major sites of fat synthesis in the body? 140. more LDL sucked from blood and blood LDL level will go down.: Increas- ing LDL receptor for cholesterol will lead to: 20 / Glucose and ketone bodies come out of liver during this time.: When does the liver generate glucose? 157. 5 mM: What is normal glucose and ATP level? 158. PEPCK: Glucagon stimulates for gluconeogenesis. 159. No. RBCs can only use glucose as energy source: Do RBCs use ketone bodies during prolonged fasting? 160. a. does not need any more food Leptin controls the eating behavior- eat less, metabolize more: Leptin signals to the brain that the body: a.does not need more food b.to increase food intake 161. True. Need exercise: T/F Lowering blood glucose is not enough because there will still be higher fat. 162. Adipose tissue: What secretes leptin? 163. eat more, metabolize less: Ghrelin which is secreted from the colon tells the body to: 164. from adrenal gland and ovary: Where does testosterone come from in women? 165. excessive growth of hair due to high levels of testosterone: What is Hir- sutism? 166. irregular menstrual periods: What is Oligomenorrhea? 167. C. It decreases mevalonate formation.: Regular exercise may change body cholesterol mainly because: A. It prevents cholesterol synthesis from mevalonate. 21 / B. It increases mevalonate synthesis. C. It decreases mevalonate formation. D.It prevents cholesterol absorption in intestines. 168. C. semi-conservative: DNA is: A. conservative B.partially-conservative C. semi-conservative D.liberal 169. bidirectionally: DNA replication starts the origin and proceeds . 170. 5' to 3'; DNA polymerase: DNA synthesis proceeds in the direction and is synthesized by . 171. E. none of the above: DNA molecules differing in linking numbers are called: A. isotopes B.anomers C. cocatamers D.enantiomers E. none of the above 172. D. telomeres: Which of the following determines the number of times a somatic cells can divide? A. protomer B.exons C. introns D.telomeres 22 / E. none of the above 173. DNA = telomeres RNA = poly A tail: DNA life is determined by: RNA life is determined by: 174. DNA topoisomerase II (DNA gyrase): What enzyme in DNA replication that relieves strain and changes linking number? 175. DNA helicase: What enzyme unwinds the DNA? 176. Okazaki fragments: What are the fragments called that are produced by the lagging strand during DNA replication? 177. Primase lays RNA primers: What is laid before DNA polymerase III can insert DNA bases? 178. It seals the nicks in the newly formed DNA strand.: What is the function of DNA ligase? 179. DNA polymerase I = replication clean-up, repair, and recombination DNA polymerase II = probably responsible for DNA repair DNA polymerase III = responsible for DNA replication: What are the functions of the 3 DNA polymerases? 180. Ames Test: What test can be done to determine if something is a carcinogen? 181. The mutation will be fixed, using the good strand as a template. Only if both strands are mutated will a mutation hold.: If one DNA strand has a mutation, what will happen? 182. UV light: Pyrimidine dimers form when DNA is exposed to .