NAME NETWORK ID MCB 450 Exam 1 February 8 2024 FORM B KEY This exam consists of 50 questions for a total of 150 points Choose the BEST answer from the available choices 1 The uncoupler 2 4 dinitrophenol DNP prevents ATP synthesis while allowing electron transport to proceed because a DNP is capable of transporting protons across the membrane dissipating the proton gradient b DNP prevents the buildup of a proton gradient by altering the electron transfer complexes such that they no longer pump protons c DNP binds to the ATP synthase and acts as an inhibitor of the enzyme d DNP transports protons out of the mitochondria after they are pumped out of the matrix e DNP inhibits complex I on the ETC to prevent electron transport 2 Why cytosolic NADH might yield potentially less ATP than mitochondrial NADH a Cytosolic NADH always loses energy when transferring electrons b Once NADH enters the matrix from the cytosol it becomes FADH2 c Electron transfer from cytosol to matrix if using the glycerol 3 phosphate shuttle d There is an energy cost for bringing cytosolic NADH into the matrix e Electron transfer from cytosol to matrix if using the malate aspartate shuttle 3 Which of the following is an inhibitor of ATP synthase by binding to the carboxylate group of glutamate of the C subunit a rotenone b antimycin A c cyanide d dicyclohexylcarbodiimide DCC e 2 4 dinitrophenol DNP 1 space 4 Why is oxygen necessary in aerobic cellular respiration a It is needed for glycolysis which begins the process of respiration in cells b It is important in creating oxaloacetic acid in the Kreb s cycle c It provides the hydrogen nuclei needed to create a proton gradient in the intermembrane d It is the final electron acceptor in the electron transport chain e It is needed to transport electrons from NADH to QH2 5 Many of the carriers in the electron transport chain are cytochromes The central component of the cytochrome capable of redox reactions is a a copper atom b a hydrogen atom c oxygen gas d water e an iron atom 6 There are 3 conformations of the beta subunit of ATP synthase with each representing different state of this enzyme Which conformation represents the active state of ATP synthase for the synthesis of ATP a O open form b L loose form c T tight form d A attach form e R release form 7 In the electron transport chain what are the pair of electron carriers in and out of complex III a NADH QH2 b FADH2 QH2 c QH2 cytochrome C d cytochrome C oxygen e NADH Fe S clusters 8 What is the source of electrons entering complex II a NADH from the TCA cycle and glycolysis b FADH2 from the TCA cycle c NAD from conversion of pyruvate to lactate d FAD from pyruvate dehydrogenase e Water 2 9 N5 N10 methylene THF is the first THF tetrahydrofolate derivative generated in cells in one carbon metabolism Which of the following amino acid provides this methylene CH2 group a Alanine b Glycine c Serine d Methionine e Histidine 10 Human dihydrofolate reductase can be effectively and specifically inhibited by the administration of a uridylate dUMP b colchicine c sulfonamide d methotrexate e 5 fluorouracil 5 FU a Vitamin B6 b Vitamin A c Vitamin C d Vitamin D e Vitamin B12 a PRPP synthetase b CPSII c Dihydrofolate reductase d Ribonucleotide reductase e Thymidylate synthase a Aspartate b ATP c CO2 d Glutamine e Glutamate the digestive process a Purines b Pyrimidines c Vitamins d Fatty acids e Proteins 11 Urine FIGlu test could be an indicator of the deficiency of which of the following vitamin 12 What is the direct target of 5 Fluorouracil a drug widely used in chemotherapy in cancer 13 What is the carbon source for the carbamoyl phosphate in pyrimidine synthesis 14 Degradation of which of the following products leads to the production of uric acid during 3 15 Lesch Nyhan syndrome is caused by a mutations in the HGPRT Hypoxanthine guanine phosphoribosyltransferase gene b mutations in the xanthine oxidase gene c mutations in the adenosine deaminase gene d an infection of the kidney e respiratory failure 16 Mycophenolic acid is a drug used to prevent graft rejection by inhibiting an enzyme in de novo purine synthesis What is the direct target of this drug a PRPP synthetase b Glutamine phosphoribosyl amidotransferase c IMP dehydrogenase d Dihydrofolate reductase e Ribonucleotide reductase 17 Which of the following answers completes the sentence correctly Guanosine is a a purine base b purine nucleoside c pyrimidine base d pyrimidine nucleoside e nucleotide 18 What enzyme is deficient in Maple Syrup Urine Disease MSUD a cystathionine alpha synthase b methylmalonyl CoA mutase c branch chain alpha keto acid dehydrogenase d tyrosinase e phenylalanine hydroxylase 19 Which of the following reactions is an example of ammonia fixation a Glutamine is converted to glutamate by glutaminase b Glutamate is converted to alpha ketoglutarate by glutamate dehydrogenase c Alpha ketoglutarate is converted to glutamate by glutamate dehydrogenase d Nitrogen in the atmosphere is converted into ammonia by some microorganisms e Alanine is converted to pyruvate by alanine aminotransaminase ALT 20 Which of the following co factor is involved in the synthesis of succinyl CoA from L methylmalonyl CoA a Pyridoxal phosphate b Vitamin C c N5 N10 methylene tetrahydrofolate d Methylcobalamin e Deoxyadenosylcobalamin 4 21 A patient with PKU Phenylketonuria should be put on a life long diet restricting which of the following a Phenylalanine b Branched chain amino acids leucine valine and isoleucine c Sulfur containing amino acids methionine and cysteine d Thiamine e Methionine 22 Which of the following statements is TRUE for the disposal of nitrogen in hibernating bears a Urea is synthesized in the small intestine rather than the liver for disposal b Nitrogen is converted to NH4 in the blood of the hibernating bears c Urea from liver is transported to small intestine to be converted to NH4 for reuse in d Bears do not dispose of any nitrogen since they sleep during the winter e Nitrogen is converted to ammonia which is released from the breath of the hibernating amino acid synthesis bears 23 A deficiency in which of the following enzymes would directly limit the ability of the body to fix and dispose of ammonia a Carbamoyl phosphate synthetase I CPS I b Carbamoyl phosphate synthetase II CPS II c Asparagine synthetase d Urease e Alanine aminotransferase 24 Amino groups of amino acids can be used for the synthesis of other nitrogen containing molecules What is the