Search found 81 matches

by claudepa
Thu Dec 31, 2015 3:53 pm
Forum: General Discussion
Topic: Measuring OD600
Replies: 5
Views: 4474

Re: Measuring OD600

I believe that all comes from the Beer Lambert law: log(Io/I)=(eps)lC Io is the intensity of the light beam arriving on the sample I is the intensity of the light beam after the sample eps is a constant l is the size of the cuvette C is the concentration of the absorbing sample in the cuvette For me...
by claudepa
Wed Dec 30, 2015 1:38 pm
Forum: Human Biology
Topic: weight loss after death
Replies: 17
Views: 54604

Re: weight loss after death

Hi. I have doubts about the role of oxygen in a supposed weight loss after death. Oxygen is converted in water in oxydative phosphorylation (ATP synthesis) in mitochondrias. Therefore there should be no loss of weight caused by oxygen. New oxygen does not arrive in cells but CO2 made by Krebs cycle ...
by claudepa
Thu Dec 24, 2015 9:11 pm
Forum: General Discussion
Topic: Is life only a system of evolving chemical reactions?
Replies: 23
Views: 15550

Re: Is life only a system of evolving chemical reactions?

Hi. Could the question be also: Is biology only a part of chemistry ? I have no answer but a personnal experience. A long time ago during my phD in biology I identified a new chemical reaction involving DNA. I had then a very interesting collaboration with organic chemists who successfuly reproduced...
by claudepa
Sat Dec 19, 2015 5:21 pm
Forum: Molecular Biology
Topic: Brunner Syndrome: could truncated MAO protein cause problem?
Replies: 1
Views: 3591

Re: Brunner Syndrome: could truncated MAO protein cause prob

Hi. You have already a very good knowledge of biochemistry. I do not know the Brunner Syndrome. However I can tell that mutated proteins are not necessarily eliminated by the cell. They can create diseases such as cancers because of their abnormal structure. For instance in cancer the ras protein (a...
by claudepa
Wed Nov 04, 2015 5:43 pm
Forum: Genetics
Topic: Leukemia - Blood Cancer.
Replies: 4
Views: 6716

Re: Leukemia - Blood Cancer.

Hi, Generally speaking cancers are caused by DNA mutations. Most of time these mutations are not hereditary. It means that they occur during our life after birth. The consequence is that the older we are the greater the chance to have a cancer. But sometimes it can be inherited. For breast cancer fo...
by claudepa
Wed Nov 04, 2015 5:10 pm
Forum: Molecular Biology
Topic: most complex abiotic (nonliving) molecules
Replies: 3
Views: 4565

Re: most complex abiotic (nonliving) molecules

HI,
Its seems to me very difficult to know on earth if an abiotic molecule is really abiotic since life can be everywhere on earth. Perhaps investigations on the moon and on mars could be more profitable for abiotic molecules since until now no life was found.
by claudepa
Tue Nov 03, 2015 4:49 pm
Forum: Cell Biology
Topic: Where do protein complexes get their quarternary structure?
Replies: 2
Views: 6004

Re: Where do protein complexes get their quarternary structu

I do not know the general answer. However for transcription factors which are active through their quaternary structure this quaternary structure can only be obtained when activation by signal transmission pathways is realized. I therefore assume that monomers are already synthetized and that their ...
by claudepa
Tue Nov 03, 2015 4:27 pm
Forum: Cell Biology
Topic: dna polymerase
Replies: 4
Views: 6381

Re: dna polymerase

Hi. We have a tendency to give DNA polymerase a special status because it is the enzyme replicating DNA. It was also the first enzyme of replication, discovered by Arthur Kornberg. However like major functions in the cells replication is assumed by nanomachines composed of many proteins working toge...
by claudepa
Tue Nov 03, 2015 12:55 pm
Forum: Cell Biology
Topic: human body cell quantification
Replies: 1
Views: 3995

human body cell quantification

Hi
Could anybody tell me if more precise measurements are known for 1) The number of cells in a human body (my rough estimation is several hundred millions cells). 2) How many different cell types in a human body (my rough estimation is 250 different cell types. Thank you