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Biological Chemistry

Saturation of Lipids - Bromine

If you add 1 drop of 5% bromine solution in hexane to 1mL each of 5% solution of lard, olive oil, and corn oil dissolved in hexane, what happens to the bromine that causes each mixture to turn colorless? If you continue adding drops of bromine to each, eventually the lipids change color. For our experiment it took 14 for lard

Saponification Water-Based Solutions

1) Since calcium and magnesium salts of fatty acids are insoluble in water, how would you expect this to affect the usefulness of soap in hard water? 2) If you were to make soap (using 4 grams of lard, 2 mL of 7.8 M sodium hydroxide & boiling it) and add it to the following and inverting, what would you expect to see as far

4 Problems

3 . Describe the role of each member of the "triad" in the mechanism of chymostrypsin. 4. Some enzymes show a bell shaped curve for enzyme activity versus pH. What conclusions can you reach about the nature and the function of groups in the enzyme? Name an enzyme which exhibits this characteristic. 7. In 1935, two famous

Biochemical pathway

You are studying a biochemical pathway in the bread mold NEUROSPORA crassa that is involved in the production of the compound C. You know that compounds A,B,D,E,F are required in this pathway, but you do not know the order in which they are synthesized. In order to study this, you isolate five auxotrophic strains that cannot syn

Synthesized triglycerides structural formulas

A normal well fed animal is given an intravenous injection of radioactive acetate labeled with 14C in the methyl group. By use of structural formulas indicate the carbon atoms that will be labeled most heavily in the newly synthesized triglycerides. Briefly justify your result.

NMR Spectrum and 13C Label

I need some help with this challenging question: 13C-NMR spectroscopy was used to detect (13)C-label accumulation in cerebral metabolites following the intravenous infusion of [1,6-(13)C]-glucose (Glc). The (1)H- [(13)C]-NMR method yielded high-quality (1)H-[(13)C]-NMR spectra. As a result, the (13)C labeling of [4-(13)C]-glut

Comparing Rates of CO2 Generation

The relative metabolic activities in an organism of glycolysis + the citric acid cycle vs. the pentose phosphate pathway + gluconeogenesis can be measured by comparing rates of 13CO2 generation upon administration of glucose labeled with 13C at C1 with that of glucose labeled at C6. Explain why this is possible.

Comparing Efficiency of Glucose Oxidation

Compare the relative efficiencies (in ATP's per mole of glucose oxidized) of glucose oxidation via glycolysis + the citric acid cycle vs. glucose oxidation via the pentose phosphate pathway + gluconeogenesis. Assume that NADH and NADPH are each energetically equivalent to three ATP's.

Fate of Carbon in Glycolysis

I am approaching this problem on paper with the "colored pencil method" for following certain labelled carbon atoms (13C). I have done research online to find a clear representation of the cycle, and both glucose and pyruvate structure. I am hoping that you might be able to follow carbon through the glycolytic pathway and expl

Signaling

Please provide an explanation... if cell surface recpetors can rapidly signal to the nucleus by activating latent gene regulatory proteins such as STAT's at the plasma membrane, why do most cell cell surface receptors use long, indirect signaling cascades to influence gene transcription in the nucleus?

Intracellular Molecule Synthesis

Two intracellular molecules X and Y are both normally synthesized at a constant rate of 1000 molecules per second per cell. Molecules X is broken down slowly: each molecule of X survives on average for 100 seconds, Molecule Y is broken down 10 times faster, each molecule of Y survices on average for 10 seconds. a. calcu

Oxidizing ethanol

Ethanol in the body is oxidized to acetaldehyde by liver alcohol dehydrogenase (LADH). Other alcohols are also oxidized by LADH. For example, methanol, which is mildly intoxicating, is oxidized by LADH to the quite toxic product formaldehyde. The toxic effects of ingesting methanol (a component of many commercial solvents) can

Michaelis-Menten equation

(See attached file for diagrams) 1. For a Michaelis-Menten reaction, k1 = 5 x 107 M-1 s-1, k-1 = 2 x 104 s-1, and k2 = 4 x 102 s-1. Calculate Ks and Km for this reaction. Does substrate binding achieve equilibrium or the steady state? 2. At what substrate concentration will an enzyme having a kcat of 30 s-1 and a Km of 0

KM of a Michaelis-Menten enzyme

The KM of a Michaelis-Menten enzyme for a substrate is 1.0 x 10-4 M. At a substrate concentration of 0.2 M, Vo=43x10^-6 M for a certain enzyme concentration. However, with a substrate concentration of 0.02 M, Vo has the same value. (A) Using numerical calculations show that this observation is accurate. (B) What is the best

Enzyme inhibitor in a reaction

Five reaction mixtures containing equal concentrations of an enzyme are prepared to the substrate concentrations indicated in the table below, and the initial rates are measured. The experiment is then repeated with an enzyme inhibitor present at a concentration of 2.2 x 10-4 M in each reaction mixture. By use of Lineweaver-Burk

Plotting a titration curve for Ala and His

Here is the problem: 1. Assume you have a solution containing 0.1 mol of Ala adjusted to pH = 0.5 with HCl. You begin adding 1.0 M NaOH. Plot (do not sketch) the resulting titration curve (pH vs. moles NaOH added) showing all inflection points. Show your calculations and be sure to state your assumptions. 2. Plot a simil

Amino Acid Charges at Various pH

Can someone check my answers to the following, please make any corrections and explanations as needed. N---Tyr---Lys---Thr---C pka 9.1 10.1 10.5 13 2.6 ph2 +1 0 +1 0 0 =+2 ph6 +1 0 +1 0 -1 =+1 ph13 0 -1 0 0 -1 =-2 N---Asp---Met---Ala---C ph2

Amino Acid Problems

(See attached file for full problem description) --- 9. An organism of unknown origin produces a potent inhibitor of nerve conduction which you wish to sequence. Amino acid analysis shows the peptide's composition to be 5 Ala, 1 Lys, 1 Phe. Reaction of the intact peptide with phenylisothiocyanate (Edman's reagent) followed

Biochem

(See attached file for full problem description) --- For problems 6-8, assume standard conditions of pH 7 and 25C, unless otherwise stated, and assume equilibrium constants in which any [H+] and [H2O] terms have been incorporated into the constant, i.e., you don't have to use [H+] in any of the calculations. 6. Th

Mutiple choice

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) In absence of oxygen, a yeast cell undergoes fermentation and uses 100 molecules of glucose. How much net ATP will be generated? A) 100 B) 36 C) 400 D) 300 E) 200 2) All the following statements pertai

Glactose sucrose fementation

Glucose and sucrose easily produced alcohol fermentation in yeast. Why didn't galactose and lactose? This was the virtual experiment. pH was set at 7 temperature 20 degrees C 20 ml of glucose was added to 1ml yeast 20ml or sucrose was added to 1ml of yeast 20ml of galactose was added to 1 ml of yeast 20ml of lact

Hender/Hasselbach and E-amino Groups

The E-amino group of lysine has a pka of 10.5: a) What fraction of these groups will be protonated in a dilute solution of lysine at pH 9.5? b) At pH 11.0?

pH of Glycine After Addition of Acid/Base

I need some help answering this questsion: If I had 1L of a 1.0M solution of glycine at the isoelectric pH (6.02) and I added 0.3 mol of HCL, what would be the new pH? What would be the pH if I added 0.3 mol of NaOH instead of the acid?

Peptide Bonds, Amino Acids and Chemical Structures

I need some help with biochemical questions: 1. How do you calculate the pH of a solution of lysine if the side chain amino group is 3/4 dissociated? 2. What is the isoelectric point of His? 3. For L-Ile, describe with drawings why it is 2S,3S? 4. What are the 6 atoms that are coplanar due to the resticted rotation about

Non-Covalent Interactions In Proteins

--Which non covalent interactions are most likely to be important in protein-protein interactions in aqueous environment? --What is the driving force for proteins that are embedded in lipid membranes?