Search found 23 matches

by 2468
Tue Dec 04, 2012 1:11 am
Forum: Molecular Biology
Topic: protiens
Replies: 1
Views: 4078

protiens

1)main roles of the following post-translation modifications of proteins: match the following a)Phosphorylaton --------- 1)Association with membrane b)Glycosidation ----------- 2)Cell-cell recognition c)Acylation ------ ---- 3)Degradation d)Ubiquitinatio -------- 4)Activation/inactivation 2) One of ...
by 2468
Tue Dec 04, 2012 1:06 am
Forum: General Discussion
Topic: pka
Replies: 6
Views: 5925

Thank you! :D
by 2468
Tue Dec 04, 2012 1:06 am
Forum: General Discussion
Topic: molar extinction coefficient
Replies: 10
Views: 14147

Its okay now! got it...had to convert concentrations from uM to M. thanks anyways :D
by 2468
Sun Dec 02, 2012 2:38 am
Forum: General Discussion
Topic: molar extinction coefficient
Replies: 10
Views: 14147

Re: molar extinction coefficient

Once you have plotted the data and drawn the line, the slope is the rise/run, the dy/dx. You can count squares on the graph paper. On the other hand, you can put the values of x and y into a spreadsheet and run a linear regression. If you do that, be sure to go back to the raw data on a graph and m...
by 2468
Sat Dec 01, 2012 6:25 pm
Forum: General Discussion
Topic: pka
Replies: 6
Views: 5925

Re:

JackBean wrote:LOL, you're really expert.

From Lambert-Beer law (A = e.c.l) calculate concentration of the color form. Concentration of colorless form is c(total) - c(color)



'Love' the sarcasm.. :/

Elaborate? Dont undertsand it.
by 2468
Sat Dec 01, 2012 5:58 pm
Forum: General Discussion
Topic: pka
Replies: 6
Views: 5925

Re:

JackBean wrote:don't you need more values?


oh yeah sorry and methyl red concentration was 12.5um....3ml of buffer used and 1ml of stock methyl red..if that helps?...really cant get my head round this..i've tried searching
by 2468
Fri Nov 30, 2012 10:45 pm
Forum: General Discussion
Topic: pka
Replies: 6
Views: 5925

pka

Hey, need help working this out: pH: 4 molar extinction coefficient: 0.0187142857 m-1cm-1 absorbance at 500nm: 1.492 [Acid form]?? (work out using molar extinction coefficient) [base form]? lg([acid]/[base])? pKa? If someone can guide me on how to do this especially the acid form....i'd greatly appr...
by 2468
Thu Nov 29, 2012 12:09 am
Forum: General Discussion
Topic: molar extinction coefficient
Replies: 10
Views: 14147

Thank you so much! :D
by 2468
Wed Nov 28, 2012 10:06 pm
Forum: General Discussion
Topic: journal
Replies: 2
Views: 2182

yes, thats what i found too...so not too sure which answer its suppose to be exactly :/
by 2468
Wed Nov 28, 2012 8:54 pm
Forum: General Discussion
Topic: molar extinction coefficient
Replies: 10
Views: 14147

Re: molar extinction coefficient

If you plot molar concentration on the X axis and absorbance on the Y axis, the slop is the molar extinction coefficient (assuming a 1cm path spectrometer cell and units of M^-1 cm^-1 for the extinction coefficient). okay...yes i've already done that...but hw wud i knw what the exact value fr the m...
by 2468
Wed Nov 28, 2012 12:40 am
Forum: General Discussion
Topic: journal
Replies: 2
Views: 2182

journal

Consider the reference: Chen, H., Hopper, S.L. and Cerniglia, C.E. (2005) Biochemical and molecular characterization of an azoreductase from Staphylococcus aureus, a tetrameric NADPH-dependent flavoprotein. Microbiology,151, 1433-1441. This is: a. A good reference for both the pKa and molar extincti...
by 2468
Wed Nov 28, 2012 12:28 am
Forum: General Discussion
Topic: molar extinction coefficient
Replies: 10
Views: 14147

Re: molar extinction coefficient

As you decrease the concentration the absorbance decreases and they should both become zero together so the intercept should be zero; that means from Y=mx+c for c=0 you only need Y=mx. For A=ecl, l=1cm and so except for its contribution to the units you can ignore it. That leaves you with A=ec, whi...