14,997 reputation
11229
bio website
location United Kingdom
age
visits member for 2 years
seen 2 hours ago

From the era before Sanger sequencing was invented.


Aug
27
comment Does E. coli survive at any pH level?
Also you need to clarify - grow, or merely survive?
Aug
26
comment Enzyme Assay, absorbance change to concentration change
This looks correct to me, although it odd not to relate the activity to the amount of enzyme that was added to the reaction - the Vmax that you have calculated is a property of the exact assay conditions used.
Aug
26
comment Enzyme Assay, absorbance change to concentration change
No need for a standard curve if you have an extinction coefficient, as in this case.
Aug
26
comment Modelling how much cadmium a cell will be able to chelate with phytochelatins
If you know the stoichiometry and dissociation constant of the binding interaction this should a straightforward task. If the aim is to discover the stoichiometry via modelling, it's unclear to me how that could work. I'm probably missing something - maybe you could expand your question, and/or make it more specific?
Aug
25
comment Calories burn rate calculation — scientific studies
If you are measuring a rate (calories burnt per until time) why would the time matter - are you suggesting that the rate varies over the period of exercise?
Aug
23
comment How do I interpret this graph regarding introduced genes and virus-infected cells?
For -/- and +/+ see this recent answer: biology.stackexchange.com/questions/20593/what-is-an-ihh-mouse/…
Aug
23
comment Why isn't Bubonic Plague as virulent as it once was?
@har-wadim - very interesting - thanks!
Aug
23
comment Do alternative start codons code for methionine after transcription?
Duplicate biology.stackexchange.com/questions/604/… also biology.stackexchange.com/questions/1629/… It seems to be the case these codons are still recognised by fMet-tRNA in the context of a translational start. See also WP en.wikipedia.org/wiki/Start_codon
Aug
22
comment Regarding the difference between cDNA library and RNA sequencing (Biochem. technique)
PCR is carried out with a DNA polymerase, which can only deal with DNA as a template. The exception to this is of course reverse transcriptase, but that can't be used in a PCR because it isn't thermostable and it can't copy the DNA copies that it makes from an RNA template, so exponential amplification cannot take place.
Aug
22
comment Regarding the difference between cDNA library and RNA sequencing (Biochem. technique)
I mean that a cDNA library exists as something tangible, not just in a computer.
Aug
22
comment How to estimate the DNA density in human sperm head?
@Bez I assume the aim is to get pg per um3 or something similar.
Aug
22
comment How to estimate the DNA density in human sperm head?
I don't understand what the value 4-5 microns refers to. If it is supposed to be a volume it should have units of volume.
Aug
19
comment Is there a difference between drinking water straight from the tap compared to leaving it to sit?
@Chris most European countries use chlorination - see lenntech.com/processes/disinfection/regulation-eu/…
Aug
19
comment Is there a difference between drinking water straight from the tap compared to leaving it to sit?
@Raoul In fact H. pylori prevalence worldwide is estimated to be 50% (and e.g. 30-40% in the UK). Most people have asymptomatic infections.
Aug
17
comment Pectinase Enzyme Assay
If the blank is at all turbid or coloured you should be using it to calibrate/zero the instrument (rather than using water or buffer). Is that what you are doing?
Aug
17
comment Pectinase Enzyme Assay
Is the enzyme blank cloudy/turbid?
Aug
17
comment Pectinase Enzyme Assay
What is the substrate?
Aug
13
comment DNA extraction from agarose gel
Yes, we used to call this method 'freeze-squeeze'.
Aug
12
comment are sperms considered living
@J.Musser thanks, I hadn't previously thought of this distinction. However it still creates some problems. Imagine a species going to extinction, with two males and one female left. There are three living organisms in this species. Then the female dies: the males are no longer living organisms. As far as I can see the only counter to this is to say that the 'group' has to be large to meet the definition of living, but this is even more problematical.
Aug
12
comment Why is oxygen needed for the electron transfer phosphorylation?
Since oxygen was late on the scene it could be that reducing it was originally a method of detoxification.