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Upload an image of your answer to this question. Draw the complete structure of a tripeptide (three amino acid residues) of your choice that contains an amino acid with a neutral R group capable of forming H-bonds (residue 1), a second amino acid with an R group that has an isopropyl structure (residue 2), a third amino acid with an R group containing two fused aromatic rings (residue 3). Label each amino acid with its three-letter code and assume a pH of 7.4.  

The figure below is of the x-ray structure of this peptide. Residues 37 and 18 interact with each other. Identify the type of bond or interaction that they (residues 37 and 18) have (i.e., covalent, ionic, hydrogen bond, and so on), and state whether a link like this would be most likely to be found in a peptide exposed to an oxidizing environment, a reducing environment, or no effect. Image Description  A 3D protein structure showing the positions of cysteine residues (Cys4, Cys11, Cys18, Cys30, Cys36, and Cys37) highlighted in yellow. The protein has an N-terminal (N) and C-terminal (C) with distinct secondary structures: alpha-helices in red and beta-sheets in blue, connected by green loops. The cysteine residues form disulfide bonds, contributing to the protein’s stability and shape.

A random sample of 525 Penn State students were asked whether they are originally from Pennsylvania. We will study those that responded “yes”. The following Minitab output summarizes the results of those that responded “yes”. Examine the descriptive statistics provided above, which statement is NOT true?

Questions 10–12 You’ll answer the questions by typing the letter that corresponds with the correct answer. This table will also be in a dropdown for each question. Identify these cofactors or coenzymes and, from the metabolic reactions we have encountered, name a reaction or enzyme that requires the cofactor. Some answer options may be used more than once, and some answer options will not be used. Some questions have more than one acceptable answer that will receive credit, but you only need to select one example that is correct. That is, you can only pick one answer even if there is more than one that would be correct. Molecule Names Enzymes and Reactions A. acetyl-CoA K. acetyl-CoA carboxylase B. acyl carrier protein L. carnitine acetyltransferase  C. biotin M. citrate lyase  D. carnitine N. citrate synthase  E. cobalamin O. dehydrogenase F. coenzyme A P. fatty acid synthase G. GDP Q. fatty acyl CoA synthetase H. HMG-CoA R. hydratase I. NADPH S. isomerase  J. NADP+ T. methyl malonyl mutase U. propionyl-CoA carboxylase  V. pyruvate carboxylase  W. racemase  X. thiolase  

  Image Description The picture depicts the structure of epinephrine. It consists of a six-membered benzene ring with three substituent groups. Attached to the bottom carbon of the ring, the 4 position, is a hydroxyl group. Attached to the lower left carbon of the ring, the 3 position, is a hydroxyl group. Attached to the top carbon of the ring, the 1 position, is CH(OH)CH2NHCH3.   The structure of the hormone epinephrine (adrenaline) is shown. Which common biomolecule would best serve as the starting material for synthesizing this compound? Give the structure, name, or abbreviation.  (1 pt.)    Epinephrine acts on liver cells through a G protein-coupled receptor and acts similarly to the hormone glucagon. Does the action of epinephrine promote the synthesis or breakdown of glycogen?  (1 pt.)    Both epinephrine and glucagon activate the same intracellular messenger, 3’,5’-cyclic AMP (cAMP). Explain how increased levels of cAMP in the cell are able to control both the synthesis and breakdown of intracellular glycogen, beginning with GTP bound to the α-subunit of the G protein receptor. (4 pts.) 

Treatment of a polypeptide with cyanogen bromide (chemically selectively cleaves peptide bonds on the carboxy side of Met residues) followed by Edman degradation of each of these fragments, gave these four fragment sequences. 1. Asp-Ile-Lys-Gln-Met, 2. Lys, 3. Lys-Phe-Ala-Met, 4. Tyr-Arg-Gly-Met  Trypsin hydrolysis of the same polypeptide followed by Edman degradation of each fragment gave these four sequences. 1. Gln-Met-Lys, 2. Gly-Met-Asp-Ile-Lys, 3. Phe-Ala-Met-Lys, 4. Tyr-Arg  Based on this information, write out the sequence of the peptide.

One of the proposed metabolic roles of lactate involves a metabolite shuttle between two types of cells within the brain. Glu is the primary excitatory neurotransmitter in the brain. The proposed shuttle system is shown in an illustration from the above-mentioned article and depicts, among other things, the recycling of Glu.  Image Description This picture depicts a chain of events that occurs in and between a glutaminergic neuron and an astrocyte, two types of cells within the brain. Two different reaction cycles are shown.   In the first, La (lactate) begins in the astrocyte. It is able to pass out of the astrocyte and into the glutaminergic neuron. There, in the presence of LDH (lactate dehydrogenase), lactate is converted into Pyr (pyruvate). Here the two reaction cycles intersect with each other. In the presence of AAT (alanine amino transferase), pyruvate is converted into Ala. Simultaneously, this allows Glu in the glutaminergic neuron to be converted into 2-oxoglutamate. The Ala is then able to pass out of the glutaminergic neuron and back into the astrocyte. In the astrocyte, the entire process is reversed. Ala is converted back into pyruvate in the presence of AAT, allowing 2-oxoglutamate in the astrocyte to simultaneously be converted into Glu. Pyruvate is then converted back into lactate in the presence of lactate dehydrogenase. At this point, the cycle repeats.   In the second cycle, Glu begins in the glutaminergic neuron. It is able to pass out of the glutaminergic neuron and into the astrocyte. There, in the presence of an unnamed enzyme, NH4- is added to Glu to create Gln. The NH4- was provided by converting the Glu produced in the previous cycle (through conversion of Ala into pyruvate) back into 2-oxoglutamate in the presence of GDH (glutamate dehydrogenase). This creates a new 2-oxoglutamate that can be converted into Glu again the next time the first cycle brings Ala into the astrocyte. Meanwhile, the Gln that was created by the addition of NH4- is able to pass out of the astrocyte and into the glutaminergic neuron. There, the entire process is reversed. Gln is converted back into Glu and a free NH4- in the presence of an unnamed enzyme. This regenerates the Glu in the glutaminergic neuron that began this cycle. Meanwhile, the released NH4- is added back to a 2-oxoglutamate by glutamate dehydrogenase, re-forming the Glu that was transformed into 2-oxoglutamate in the first reaction cycle when pyruvate in the glutaminergic neuron was converted into Ala. The cycle then is able to repeat.   What is the advantage gained by the glutamatergic cell in shuttling lactate when it appears that a pyruvate shuttle would be more direct? (1 pt.)  What role does Ala play in the shuttle system? Again it appears that shuttling pyruvate would be more direct. (1 pt.)  Gln is the amino acid with the highest circulating concentration in the blood. What major role does it play in nitrogen metabolism? (1 pt.)  The article by Gladden cited in the previous question talks about ATP control of glycolysis. Give the name of one enzyme in the citric acid cycle that is controlled by ATP or ADP/AMP levels. (1 pt.)  “Increased nervous system activity requires increased energy metabolism in neurons. The conventional view is that neuronal energy metabolism is fuelled by glucose oxidation (Chih et al. 2001). The action potentials of neuron activity result in Na+ entry and K+ efflux which activates Na+-K+ -ATPase in the neuronal plasma membrane; this ATPase pump activity, in turn, leads to decreased ATP, increased ADP, increased Pi, and increased AMP, standard activators of glycolysis, the TCA cycle and mitochondrial oxidative phosphorylation. ATP synthesis will increase via these energetic pathways with a concomitant utilization of intracellular glucose that lowers glucose, leading to…”  Acetyl CoA and Glu can react to form N-acetyl Glu, which is a potent activator of the enzyme glutamate dehydrogenase. Briefly explain why this compound is well-suited to regulate the activity of this enzyme. (2 pts.)   

Based on the box plot from the previous question and the descriptive statistics below, which value would you report as the typical number of miles driven on 8/6/2025 for this sample of drivers?

Upload an image of your drawing. The role of lactate (CH3CH(OH)CO2-) in metabolism was evaluated in a review article on lactate metabolism by L. B. Gladden (full citation: Gladden, L. B. (2004). Lactate metabolism: a new paradigm for the third millennium. The Journal of physiology, 558(Pt 1), 5–30). The paragraph below is from the article. La- is lactate. “La- can no longer be considered the usual suspect for metabolic ‘crime’, but is instead a central player in cellular, regional and whole body metabolism. Overall, the cell-to-cell lactate shuttle has expanded far beyond its initial conception as an explanation for muscle and exercise metabolism to now subsume all of the other shuttles as a grand description of the role(s) of La- in numerous metabolic processes and pathways.” One of the proposed metabolic roles of lactate involves a metabolite shuttle between two types of cells within the brain. Glu is the primary excitatory neurotransmitter in the brain. The proposed shuttle system is shown in an illustration from the abovementioned article and depicts, among other things, the recycling of Glu. Image Description This picture depicts a chain of events that occurs in and between a glutaminergic neuron and an astrocyte, two types of cells within the brain. Two different reaction cycles are shown.   In the first, La (lactate) begins in the astrocyte. It is able to pass out of the astrocyte and into the glutaminergic neuron. There, in the presence of LDH (lactate dehydrogenase), lactate is converted into Pyr (pyruvate). Here the two reaction cycles intersect with each other. In the presence of AAT (alanine amino transferase), pyruvate is converted into Ala. Simultaneously, this allows Glu in the glutaminergic neuron to be converted into 2-oxoglutamate. The Ala is then able to pass out of the glutaminergic neuron and back into the astrocyte. In the astrocyte, the entire process is reversed. Ala is converted back into pyruvate in the presence of AAT, allowing 2-oxoglutamate in the astrocyte to simultaneously be converted into Glu. Pyruvate is then converted back into lactate in the presence of lactate dehydrogenase. At this point, the cycle repeats.  In the second cycle, Glu begins in the glutaminergic neuron. It is able to pass out of the glutaminergic neuron and into the astrocyte. There, in the presence of an unnamed enzyme, NH4- is added to Glu to create Gln. The NH4- was provided by converting the Glu produced in the previous cycle (through conversion of Ala into pyruvate) back into 2-oxoglutamate in the presence of GDH (glutamate dehydrogenase). This creates a new 2-oxoglutamate that can be converted into Glu again the next time the first cycle brings Ala into the astrocyte. Meanwhile, the Gln that was created by the addition of NH4- is able to pass out of the astrocyte and into the glutaminergic neuron. There, the entire process is reversed. Gln is converted back into Glu and a free NH4- in the presence of an unnamed enzyme. This regenerates the Glu in the glutaminergic neuron that began this cycle. Meanwhile, the released NH4- is added back to a 2-oxoglutamate by glutamate dehydrogenase, re-forming the Glu that was transformed into 2-oxoglutamate in the first reaction cycle when pyruvate in the glutaminergic neuron was converted into Ala. The cycle then is able to repeat. La- is lactate, Pyr is pyruvate, AAT is alanine amino transferase, 2-oxoglu (2-oxoglutamate) is another name for a-ketoglutarate, GDH is glutamate dehydrogenase, LDH is lactate dehydrogenase  One of the reactions shown in the diagram is the conversion of Glu to Gln. Draw out this reaction. Include the structures of the substrate and product, as well as the key intermediate structure in the reaction, along with any cofactors or co-reactants required for the reaction. (2 pts.)  Draw out the reaction that takes 2-oxoglu, which is another name for a-ketoglutarate, directly to Glu (the reaction labeled GDH reaction). You may use names of the substrate and product; structures are not necessary. Include any cofactors and give the enzyme name. (2 pts.) 

We conducted a survey of 300 RIT students and one of the survey questions was: “Did you use a ride-service (such as Uber/Lyft) during Fall 2024 semester?” Yes or No We are interested in developing a confidence interval with the survey results. Assume all assumptions have been met. Which statistical feature would we use and why?