Calculate the plasma osmolality and comment on its significance.

Explain the role of eicosanoids formed as a result of metabolism of n-3and n-6 fatty acids in human physiological processes. In your answer consider data from relevant observational (epidemiological) studies alongside explanation of mechanism of action of these eicosanoids.2.

c) The enzyme contains 5 disulfide bonds. Given that this is a secreted enzyme, is this expected or surprising? List the 5 disulfide bonds below (e.g., "Cys41 - Cys142") and circle the one that you would expect to be most important for enzyme activity.

a) Briefly describe the overall tertiary structure of MHETase. (Approach this as in Problem 1.) How many and what kind of domains does the polypeptide have (e.g., what class)? Even if you think that there is a single domain, would there be a way to divide it into 2 sub-domains? Specify which parts of the polypeptide below to each domain or sub- domain (unless you think that there is only 1 domain and no sub-domains).

b) MHETase is believed to use a catalytic triad to hydrolyze the ester linkage in MHET, just like the catalytic triad in the serine proteases. Examine the structure of MHETase complexed with the analog and identify the 3 residues in the catalytic triad. For each one, find the most important distance between that residue and its partner in the mechanism and fill out the chart, identifying the 2 atoms used and the distance between them. Also identify the secondary structure in which it is found (e.g., a-helix, ß-strand, tight turn, or loop). Residue (name & #) Ser His Asp Identify the most relevant inter-atomic distance and identify the atom name (click on it in PyMOL) (e.g., "CB" or "C4" or "OG") Atom in Ser: Atom in substrate analog: Atom in His: Atom in Ser: Atom in Asp: Atom in His: distance between atoms (Å) 2° structural context/nWhat other residues in the enzyme are important for binding MHET? Identify at least 4 that seem to play an important role. Residue (chain, name & #) Atom of the residue and the substrate analog? distance Type(s) of interaction (e.g., H-bond, between charge-charge, coordination bond, van der Waals) atoms (Å) 2⁰ structural context Which, if any, of these residues might explain why MHET is a good substrate, but BHET is not? And how would it explain the substrate specificity?

Consider the reaction mechanism shown below for this question: CH₂ CH₂ NH₂ CH₂ CH₂ Lyase O Ligase 6 Oxidoreductase Transferase O Hydrolase CH₂₂ CH₂ 0,PO 5 CH CH₂ What class of enzyme does this belong to? O Translocase CH₂ 20,P H₂C CH₂ CH₂ 2 CH₂ 20,PO CH₂ 20,PO Net₂

d) Going back to the first question, briefly discuss the roles of the 2 (sub)domains in the mechanism of MHET hydrolysis. Broadly speaking, what role does each one play?

Suppose that the following sequence describes the reactions of two different substrates catalyzed by one enzyme:Enzyme Kinetics 2-43 The initial concentration of substrates, products, and enzyme are: Cs₁ = 0.1mol/L, Cs₂ = 0.3mol/L, Cp₁ = Cp₂ = 0, Ces₁ = Ces₂ = 0,and C = 0.05mol/L. Show the changes of Cs₁ Cs2 ,Ces1 Ces2,Cp1, and Cp₂ with respect to time by solving the simultaneous differential equations.

The Delta Plus variant of SARS-CoV-2 has been found to have an amino acid substitution in the spike protein known as K417N. The spike protein is considered to be how the viral particle attaches to the host cell for infection. Based on your knowledge of amino acid side chain chemistry, speculate how this amino acid substitution (i.e. N replaces K at position 417) could lead to an altered potentially improved interaction with the host protein receptor. Your answer should include the following:

Short Answer 1. A study on rat metabolism is being conducted. There are 3 different groups of rats involved. Group 1 Diet rich in fat but normal in carbohydrates and protein Group 2 Diet rich in protein but normal in carbohydrates and fat Group 3 Diet rich in carbohydrates and normal protein and fat a. The three groups are kept in identical environments with opportunities for physical activity. Write a hypothesis, predicting the expected energy levels for each group for the first 4 days of the experiment. Please explain your predictions. (A-4, 2-C) 3 Scanned with CamScanner b. You run the experiment for 20 days and then analyze the results. How do you expect the three groups to compare in terms of body size/mass and general health? (A-4, 2-C) de toutes 2. Track athletes often say that the 400m sprint is much more exhausting and harder on the legs than the 100m sprint. What type of respiration would a 400m sprinter rely mostly on as they reach the end of the race? Explain. (A-4, 2-C) 3. Several anti-nuclear war protesters claim that inhabitants of the earth did not perish from nuclear bombs or the radiation afterwards, that the people would slowly succumb to changes brought on during the "nuclear winter". During a "nuclear winter", a lot of dust would be drifting in the atmosphere causing the blockages of the sun's electromagnetic spectrum. Based on your knowledge of photosynthesis, what impact would this have on humans that are still alive and why? (A-4, 2-C) Scanned with CamScanner

Bonus: Determine the primary sequence of the following peptide. (10 Pts) A. Trypsin treatment generated the following fragments: (LFVCYMGFR) (HDITNAATYR) (AEK) (CPS) (K) (QIVAAR) (LWVANK) B. Chymotrypsin treatment generated the following fragments: (AEKL) (F) (VCY) (MGF) (RHDITNAATY) (RL) (W) (VANKKQIVAARCPS) C. Thermolysin treatment generated the following fragments: (LF) (VCY) (MGFRHD) (ITNAATYR) (AEK) (LW) (VANKKQ) (1) (V) (AARCPS) Legend: Trypsin = Lys & Arginine (R.) Chymotrypsin = Tyr, Trp, Phe, Leu (R.) Thermolysin = Leu, Val, lle, Met (R₂)