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Biological Chemistry

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

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.

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

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


(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

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?

Intracellular second messenger

What Intracellular second messenger is the primary regulator of the physiological response of photoreceptors to stimulus? AND What intracellular messenger is the primary regulator of adaptation of photoreceptors? Please explain, but most of all with the right answer and explanation!

Beta bends or reverse turns

The amino acid sequence shown below represents a portion of a peptide bond obtained from a large protein: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 His - Ile -Thr - Arg - Phe - Phe - Pro - Cys - Met - Gly - Glu - Ala - Ile- Pro - His - 16 17 18

Questions Based on the Action of Pyruvate

Hi, I need some assistance with the following questions: 1. The disease beriberi, which results from a dietary deficiency of vitamin B1 (Thiamine) is characterized by neurological and cardiac symptoms, as well as increased levels of pyruvate and alpha- ketoglutarate in the blood. How does a deficiency of thiamine account for


What is the purpose of ferementation after glycolysis? and.. Why use starved starved yeast rather than sugar fed yeasts for fermentation?

Life on Earth - 8 Short Questions.

Life on Earth - Biological Concepts from the Non-Science Major Perspective Quiz: (1 point each) 1. Describe the difference between and exergonic and endergonic reaction? 2. Why do environmentalists claim that an increase in forests, i.e. rainforests, will slow down the effects of global warming? 3. Explain how fats a

Oxidation of palmitate

Estimate the amount of energy a mammal can obtain from the oxidation of palmitate, in the liver under conditions of ketosis, relative to the amount obtainable under conditions of a balanced diet with adequate consumption of glucogenic fuels.

GRE subject Biochem

Discuss the feasibility of using methylation analysis to distinguish between each of the following pairs of carbohydrates: A) Maltose and Trehalose B) Maltose and Amylose C) Amylose and Cellulose

Inhibitors: Irreversible and Reversible

Question: It is possible to distinguish between an irreversible inhibitor and a classical mixed type reversible inhibitor by measuring Vmax of the enzymatic reaction as a function of [E]t in the absence and presence of the inhibitor. What does the slope represent in each case? What does the X-axis intercept represent in

Biophysics - Calculating deltaG

In one day the average person secretes about 2.5 litres of gastric juice into the stomach. The pH of the cells in the stomach lining that perform the secretion is about 7 (the same as for all cells) and the pH of the stomach is about 1. Thus, H+ ions must be moved against an H+ gradient. The free energy change for moving molecul