mk_2007

ok. I understand half of that. But why are you taking out 5 μg? I dont understand how you get to that?

I'm trying to write my lab report up and I'm getting really confused about a certain calculation! I made a 1% agarose gel, and Basically, I added 5 μL of ethidium bromide to a solution (solution= 0.5 g agarose and 50 μL TAE) and the bottle said the ethidium bromide had a concentration of 5 μg/μL. so what concentration of ethidium bromide am I adding to my solution? Help would be much appreciated!

Hi! I have just done a maldi tof- maldi tof tof, and am trying to calculate the b and y ions from the spectra. I have found an amino acid which is almost perfect except one thing! I get a peak corresponding to a tyrosine residue for y ions, but nowhere can i see one for b ions! can anyone suggest why this might be? x

Hi! basically, I'm doing some practice questions, and came across one, which i'm not quite sure how to calculate.. I had a go at it and this is my answer.. can anybody tell me if the method I used is correct, or if I'm going about this the wrong way!! The question was.. a lysis solution contained 50 mM Tris, 100mM NaCL and 0.01% (w/v) SDS. How would you prepare 100 ml of this solution? So what I did was : Start Final Volume x Concentration= Volume x concentration So Taking a start concentration of 1 M, then TRIS = T x 1M = 100 ml x 50 x 10-³ M NaCl = N x 1M = 100 ml x 100 x 10-³ M SDS= 0.01% is the same as 0.01 g/100ml. Therefore this can be taken as the concentration. So Volumes of each concentration of solutions required to make up 100 ml are TRIS= 5ml NaCl= 10 ml SDS= 0.01 ml H2O = 84.99 ml (100-5+10+0.01)

Hi! Another question!! If you clone a gene, lets call it B, as a Xho I/Hind III fragment into a vector, then digest this vector with Hind III/Sal I, why would Xho I and Sal I sites be missing from the map? I know this is because, there is no restriction site for the Xho I and Sal I enzymes in the vector, but why? what could have happened to delete a restriction site? Help would be much appreciated!!!

Hi! I was wonderng if anyone knows why its useful to include uncut DNA in an electrophoresis when analysing the cut DNA restriction fragments?

How do I convert ( glucose concentration ) µg per ml into µM? For example 10 µg per ml?

Hey.. I was wondering.. I have just done a lab investigating kinetics of yeast invertase... I mixed invertase, 0.1M phosphate bufer and 0.2M sucrose (substrate) in a test tube and put it in a water bath. at 1,5,10,15 etc minutes I removed some of the invertase and added distilled water.. I was wondering.. why and how does the addition of distilled water stop the reaction occurring?

ah ok. Thank you I understand. one more thing.... with G-proteins, in G-coupled protein receptors, when the GDP is removed and replaced with GTP, is there a specific name for this process ? and is this an example of post translational modification?

a list would be good thanks. I thought glycosylation was co-translational and not post?

What post-translational modifications play a role in intracellular signalling?

what I mean is..why is it so important to have peptides and gastric amino acids digested by pepsin?

Is the digestion of protein the stomach by pepsin directly importnt for protein breakdown per se or is there another purpose or benefit in the production of gastric amino acids and peptides?

A DNA molecule containing multiple identical repeats and a single unique sequence was examined by C0t analysis. 10% of the DNA had an observed C0t1/2 value of 2 x 10-3 mol.l-1.s and the remaining 90% an observed C0t1/2 value of 8 x 10-3 mol.l-1.s. What fraction of the total DNA is contained in one repeat? How do I figure tis out? its multiple choice out of a. 0.25% b. 2.5% c. 4% d. 10% e. 90%

but, then what is the difference between a signal anchor and a GPI modification site?