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Biological Chemistry

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?

GRE Study Guide

Describe the molecular events that generate the "dark current" in photoreceptor cells; explain the impact of this cycle on the typical resting membrane potential, and how light leads to a hyperpolarization of the membrane. Please Explain and be accurate

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!