Recent content by sontag

This is a highly informative and interesting Biology website by Dr John Kimball: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/

The p53 gene which is damaged or missing in many cases of cancer is located on chromosome 17 which is one of the smaller chromosomes? Does the size of chromosome 17 make it easier/more difficult for p53 to be damaged/removed? Do chromosomes respond to ultrasound? Could a damaged chromosome...

What exactly is the "blood-brain" barrier and does it play any role in Alzheimer's or Parkinson's disease? I read that blood vessel cells have no gaps between them in the brain - is this the blood-brain barrier? Also when these blood vessel cells are forced apart by high blood pressure charged...

I got the information from Doctoxyn's post (where tau protein is mentioned): http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15542981 It actually says "younger" people and not "young" people.

The fact that young people with head injury can get microtubule damage suggests that inflammation could be a contributing factor to Alzheimer's, because old people in their 80s have a weaker immune response than young people (there is an inflammatory immune response to free radicals that...

Strands are more likely to break where there is a long CG sequence e.g. CG CG CG CG CG CG CG.Why is this? Also when crossovers occur are enzymes needed to mediate exchange of genes?

This links explains that the extra hydrogen bond for C-G is part of the reason for the lower error rate in transcription compared to A-T.Deoxynucleotides are in chemical equilibrium with the template strand and C-G is the combination most likely to be present at a C or G location when DNA...

What changes would have to be made to a cell so that when it divides the genes in the daughter cells are exactly the same,in the same order and number on the chromosomes, as they were in the parent cell?

But surely there is a limit to the size of molecules in a cell? And very large molecules would be prone to errors when they are made- there must be a limit to molecule size, even outside cells?

What stops cells differentiating in vertebrates before the 8 cell stage?

How many different molecules are people made from? Are there lots of new molecules to be discovered and if so,how is this known?

Why does a fast speed result in more errors.And why do dATP and dTTP have 5-50 times the error rate of dGTP and dCPT for bacteria that live in hot water (see post above). Would there be a higher density of DRiPs expressed on the cell surface and is there any chemical process in the body...

Could the soundwaves/pressure from a blow to the head cause organelles to be damaged?

I found on the web at http://www.antigenics.com/products/tech/hsp/ that HSPs are bound to peptides and the bound system is released into the bloodstream when some cells die,eliciting an immune response by binding to the CD91 receptor on macrophages.Can be an early warning to the immune system...