BMB_401_Practice_Exam_II_Key-1 - Practice exam BMB 401...

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Unformatted text preview: Practice exam BMB 401 Exam 2 Page 1 1) a ­c. Please state three of the major products of the glycolytic pathway a_ATP b NADH c Pyruvate d) Please identify the enzyme that catalyzes the first committed step of glycolysis. Phosphofructokinase 1 2) a ­b. Two enzymes were discussed regarding catalysis of the first reaction of glycolysis. Please name these two enzymes that can catalyze this reaction. A Hexokinase b _Glucokinase c.Which of these two enzymes is negatively regulated by its product? _ Hexokinase d. What is this product? Glucose 6 ­Phosphate 3) a. During glycolysis, a 6 ­carbon molecule is split in to two 3 ­carbon molecules. What is the enzyme that catalyzes this reaction? Aldolase b. ­c. Please name the two 3 ­carbon molecules which are the products of this reaction. b.Dihydroxyacetone phosphate, c. Glyceraldehyde 3 ­Phosphate d. Does the enzyme, listed in part 3a, catalyze the reverse reaction during gluconeogenesis? Yes, this enzyme catalyzes a reversible reaction. 4) Please name two cofactors that act as carriers of carbon containing groups a Tetrahydrofolate_b Biotin (also: acetyl CoA, Thiamine pyrophosphate (TPP), 5’deoxyadenosyl cobalamin) 5) Name two vitamins that do not function as cofactors. a)Vitamin C b.Vitamin D 6) a) What global signal stimulates the rate of gluconegenesis? Glucagon b) This global signal is released when serum glucose levels are {high, low}. 7) Please state two means by which the enzyme, δ ­aminolevulinate synthase (δALA), is regulated. a) Transport of δ ­ALA into the mitochondrion is blocked by high heme concentration, b) Translation of the mRNA to produce this enzyme is inhibited by high heme concentrations 8) During the biosynthesis of heme, the symmetric ring, uroporphyrinogen III is formed. TRUE FALSE 9) a) Please state the biochemical basis for acute intermittent porphyria. Porphobilinogen deaminase deficiency results in porphobilinogen and δ ­Aminolevulinate excess, b) Please name the major transporter of iron in the blood. Transferrin (Ferritin is the intercellular storage protein) 10) Please state the organ location and the purpose of biliverdin reductase a)Location:Spleen_ b) Purpose: Converts biliverdin to bilirubin 11) Bilirubin is transported to the liver by Serum albumin 12) ∆G‡ is defined as: The standard free energy of the transition state for a given reaction 13) a) Tightly bound, inorganic cofactors: {Metals, Prosthetic groups, Coenzymes} b) Small, Organic Molecules that act as loosely bound cofactors: {Metals, Prosthetic groups, Coenzymes} Practice exam BMB 401 Exam 2 Page 2 14) One hallmark of non ­competitive inhibition is that Km equals Kmapp 15) Please identify the vitamin in Figure 1. Riboflavin 16) a) Please state the purpose of Coenzyme A as a cofactor: CoEnzyme A Figure 1 is a cofactor that carries acyl groups b) From which vitamin is this cofactor derived? Pantothenate (vitamin B5) 17) a) Please name 4 of the lipid soluble vitamins: ADEK 19b Please state the basis for the condition: beri beri. Deficiency of Vitamin B1, thiamine. 18) a) What is the function of E1 in the pyruvate dehydrogenase complex? Oxidative decarboxylation of pyruvate b) What cofactor is used by E1?_Thiamine pyrophosphate c) From what vitamin is this cofactor derived? Thiamine, B1 d) What does this cofactor do specifically? TPP is a cofactor that carries carbon ­ containing compounds. (Its main utility is that it can form a stable carbanion which can act as a potent nucleophile to attack a carbonyl group) 19) Please name 2 enzymes that catalyze irreversible steps in the glycolytic pathway a)Hexokinase b)Phosphofructokinase 1 20) Please name 2 enzymes in the gluconeogenic pathway that are used to go around the “roadblock” of glycolytic reaction 10. a) Malate dehydrogenase, b) phopsoenolpyruvate carboxykinase (the other is pyruvate carboxylase) 21) Please describe the major function of fructose 2,6 ­bisphosphate This small molecule is a potent activator of PFK1 during glycolysis. 22) At what point or points does fructose join the glycolytic pathway? In the liver, at dihydroxyaldehyde phosphate and glyceraldehyde: F1 ­P is split to yield DHAP and Glyceraldehyde – which must then be phosphorylated to enter glycolysis as GAP. In the adipocytes, hexokinase phosphorylates fructose so that it enters as F6 ­P 23) By using Graph 1, Where Vo is in µM/sec, and S is in µM, please solve for: a)Kmapp_Kmapp is  ­1(1/ ­0.25), which is 4 b) Vmax This is also 4 c) What type of graph is this?_Lineweaver ­Burke d) What type of inhibition is seen? Competitive Practice exam BMB 401 Exam 2 Page 3 24) a) Please use Figure 2 below to answer the following questions: During glycolysis, is a converted to b, or is b converted to a? In glycolysis, a is converted to b b) Is this a reversible or irreversible reaction? Irreversible c) What is the purpose of this reaction? Figure 2 The purpose of this reaction is 1) to destabilize the molecule to allow for cleaving to occur and 2) to make certain that two phosphorylated products are made d) Please identify the intermediate shown in Figure 2b Fructose 1,6 ­bisphosphate 25) Please name two positive effectors and two negative effectors of the enzyme that catalyzes the reaction discussed in question 24 a) Positive Fructose 2,6 ­Bisphosphate b) Positive AMP c) Negative Glucagon d) Negative Citrate (also ATP and H+) EC1) What enzyme catalyzes the reaction discussed in questions 24 and 25? PFK1 EC2) N-linked complex carbohydrates are transferred en bloc to asparagine residues on proteins in the endoplasmic reticulum. True False ...
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