BIOCHEM MODULE 8 EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+

1 BIOCHEM MODULE 8 EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+ True or False: The majority of reactions of the urea cycle occur in the cytosol. Correct Answer: true True or False: FADH2 yields 2.5 ATP molecules after donating electrons and hydrogen atoms to the electron transfer chain (ETC). Correct Answer: False True or False: ATP is invested in the urea cycle. Correct Answer: True True or False: There are five complexes associated with the ETC. Correct Answer: False True or False: In the production of ATP via ATP synthase, the H+ ions move from the mitochondrial matrix to the intermembrane space. Correct Answer: False 2 The urea cycle involves _________ reactions (only those in the cyclic portion of the process). - 4 - 5 - 6 - 8 - 10 Correct Answer: - 4 Which amino acids are involved in the urea cycle? A. Ornithine B. Aspartate C. Threonine D. Both A and B E. Both A and C Correct Answer: D. Both A and B Fumarate reenters the mitochondrion as which of the following molecules? - Malate - Ornithine 3 - Citrulline - Fumarase - Ammonia Correct Answer: - Malate Urea is useful for excreting nitrogen from cells due to its: - Ability to hydrogen bond with water - Ability to form ions - Large size - Low melting point - None of these Correct Answer: - Ability to hydrogen bond with water Which component of the urea cycle is also a member of the CAC? - Fumarate - Malate - Acetyl-CoA - Citrate - None of the above Correct Answer: - Fumarate 4 Oxidative deamination results in the removal of __________ from amino acids. A. N2 B. NH4+ C. NO2 D. NH2 E. NH3 Correct Answer: B. NH4+ The following chemical species is __________. Correct Answer: Urea NADH donates electrons and H+ to complex ______. I II III IV V Correct Answer: I Which of the ETC complexes do pump H+ ions? 5 Complex I Complex II Complex III Both A and B Both A and C Correct Answer: Both A and C What protein shuttles electrons from Complex III to Complex IV? - NADH dehydrogenase - Arginase - Fumarase - Cytochrome B - Cytochrome C Correct Answer: - Cytochrome C What molecule transfers electrons and H+ from both Complex I and Complex II to Complex III? - NADH - FAD - Cytochrome C - Cytochrome B 6 - CoQ Correct Answer: - CoQ In what portion of the mitochondrion does the CAC take place? - Matrix - Intermembrane space - Inner membrane - Outer membrane - Both B and C Correct Answer: - Matrix At which complex does the following reaction take place? O2 + 4e- + 4H+ → 2H2O Complex I Complex II Complex III Complex IV Both A and B Correct Answer: Complex IV 7 During the electron transport chain, protons are pumped from _________ in the mitochondria. - From the intermembrane space to the cytosol - From the intermembrane space to the matrix - From the matrix to the intermembrane space - From outside of the cell to the cytosol - From outside of the cell to the matrix Correct Answer: - From the matrix to the intermembrane space Energy released _________________ is utilized for the synthesis of ATP. - In the formation of ATP - In the digestion of proteins through the breakdown into the carbon skeleton - In the degradation of carbohydrates - As proton flow through ATP synthase - None of the above Correct Answer: - As proton flow through ATP synthase At which part of ATP synthase is ATP produced? A. FO B. F1 8 C. Axel D. Stator E. Both A and C Correct Answer: B. F1 An individual with the MERRF disease, tend to have symptoms of _________. - Blood pressure issues - headaches - High cholesterol - Muscle twitches - None of the above Correct Answer: - Muscle twitches In mitochondria, the molecule that produces ATP is located in the _______. A. Intermembrane space B. Outer membrane C. Inner membrane D. Both A and B E. Both B and C Correct Answer: C. Inner membrane 9 What process results in ATP formation? A. H2O in ATP synthase B. GTP is produced first C. Heat applied to ATP synthase D. Rotation of ATP synthase E. None of the above Correct Answer: D. Rotation of ATP synthase Which of the following is not a part of ATP synthase? A. F B. FO C. F1 D. F2 E. Both A and D Correct Answer: E. Both A and D Use the word bank to fill in the following blanks. In the word bank, each word or words is separated by semicolons. Words can be used more than once, and not all words will be used. Word bank: ADP and Pi; ATP; GTP; oxidative; reductive; citric acid cycle; electron transport chain; three; eight; ten 10 Oxidative phosphorylation occurs in ___(A)_____ phases using NADH and FADH2 generated from the ___(B)_____. Oxidative phosphorylation is the synthesis of ____(C)______ from ____(D)_______, using energy generated by the _____(E)______ reactions. Correct Answer: A) three B) citric acid cycle C)ATP D) ADP and Pi E) electron transport chain Oxidative phosphorylation occurs in three phases. The first phase in the flow of electrons to from NADH and FADH2. What happens after this first phase is complete? Correct Answer: The chemical reactions of the ETC provide energy to pump H+ ions from the mitochondrial matrix into the intermembrane space. The reactions also provide electrons and H+ to convert oxygen into water. The net result is that the H+ gradients permit a flow H+ to rotation ATP synthase, producing ATP. Describe the critical structure of the mitochondrion that are important for the production of ATP. Correct Answer: This organelle is the central hub of the energy production in the cell and has a complicated structure including two membranes. The mitochondrion has an outer membrane and an inner membrane. The outer membrane is a bilayer that has 11 porin proteins that permit ions and molecules to cross into the intermembrane space. The intermembrane space is the solution between the outer and inner membranes. The inner membrane is highly selective bilayer permitting only select ions and molecules to cross. The selectivity is crucial for maintaining specific concentrations of H+, ATP, and other species in the mitochondrial matrix. Also, the inner membrane contains the protein complexes of the electron transport chain, which accepts the electrons from the coenzymes. The matrix is the innermost space of mitochondrion where the citric acid cycle occurs along portions of fatty acid oxidation and the urea cycle. Once the NADH and FADH2 are produced by the citric acid cycle they are in proximity to the electron transport chain, so that donation of electrons and hydrogen ions is efficient.