Search found 81 matches

by claudepa
Thu Mar 23, 2017 4:01 pm
Forum: Genetics
Topic: Could anyone provide explanation on this picture Q.
Replies: 2
Views: 6536

Re: Could anyone provide explanation on this picture Q.

A,B,E are not true. D is true only for transcription. Therefore the good answer is indeed C. For E the notion of promotor in only for transcription. Replication takes place from replication origins.
by claudepa
Thu Mar 16, 2017 10:46 am
Forum: Molecular Biology
Topic: During translation, where do amino acids come from?
Replies: 2
Views: 5133

Re: During translation, where do amino acids come from?

Amino-acids, either synthetised in the cell or imported from the extracellular medium are everywhere in the cytoplasm. tRNA are charged with amino-acids by the aminoacyl tRNA synthetases and they are always present. Charged tRNA do not need to know that a codon needs an anticodon. It is just a law o...
by claudepa
Thu Mar 09, 2017 10:19 am
Forum: Genetics
Topic: DNA Identification article
Replies: 1
Views: 3987

Re: DNA Identification article

One suggestion is the role of DNA mutations in cancer immunotherapy. Cancer immunotherapy is a revolution in cancer treatment which saves many lifes in several cancers resisting classical treatments among them melanoma and lung cancer. Statistically the more mutations in DNA of cancer cells, the mor...
by claudepa
Mon Mar 06, 2017 2:40 pm
Forum: General Discussion
Topic: Could 'Spontaneous Necrosis' partly explain aging?
Replies: 2
Views: 2990

Re: Could 'Spontaneous Necrosis' partly explain aging?

I have no special competence in aging. Only a general idea that it is a multifactorial phenomenom: mutations, oxygen, hayflick law...

For the necrotic cells I suppose they are destroyed by macrophages. But aged macrophages also could be less efficient.
by claudepa
Tue Feb 21, 2017 11:49 am
Forum: Genetics
Topic: Life Extension And Regulation Of Gene Expression
Replies: 3
Views: 4838

Re: Life Extension And Regulation Of Gene Expression

Aging is not only a question of DNA sequence. We live thanks to oxygen and oxygen has toxic consequences, because of free radicals, for our cells. Studies have been performed to look for specific genes expressed in people who reach 100 years. Probably you can find the results on internet. It seems t...
by claudepa
Sat Sep 17, 2016 11:51 am
Forum: Molecular Biology
Topic: Telomeres replication?
Replies: 2
Views: 3937

Re: Telomeres replication?

I did not do a biology book review. But I always considered that the question of replication of telomers is similar for the leading strand and the lagging strand. In the absence of telomerase activity I guess that both strands shorten at each DNA replication.
by claudepa
Fri Aug 26, 2016 8:43 am
Forum: Molecular Biology
Topic: DNA supercoiling
Replies: 5
Views: 4785

Re: DNA supercoiling

my feeling is that gyrase introduces new superturns to go from negative superturns to relaxed state. So it is logical the energy is needed to make superturns. I do not know if toposisomerases need ATP but if not it would not be surprising since they only need DNA cleavage and then the energy stored ...
by claudepa
Fri Aug 26, 2016 8:28 am
Forum: Cell Biology
Topic: Liver Leukocytes
Replies: 3
Views: 4203

Re: Liver Leukocytes

Kupffer cells and Hepatocytes are very important for the liver. However I heard from liver specialists that there are 60 different types of cells in the liver. For this reason it will be very difficult to make artificial liver using stem cells.
by claudepa
Thu Aug 25, 2016 3:04 pm
Forum: Molecular Biology
Topic: DNA supercoiling
Replies: 5
Views: 4785

Re: DNA supercoiling

Hi. my souvenirs about DNA supercoiling are rather old. There are probably new data I do not know. I agree that it is clear for the circular bacterial DNA. In eukaryotes chromosome DNA is not circular. However there are sequences (MAR) of DNA which correspond to a nuclear matrix binding. This could ...
by claudepa
Wed Aug 24, 2016 10:23 am
Forum: Genetics
Topic: DNA transcription
Replies: 1
Views: 3182

Re: DNA transcription

Hi. The 2 DNA strands are complementary according to the Watson Crick rules. When RNA polymerase 2 is activated by transcription factors binding on a given sequence of one strand of DNA (the coding strand) , it will synthetize mRNA complementary to the other strand of DNA. Therefore the mRNA sequenc...
by claudepa
Fri Aug 19, 2016 10:33 am
Forum: General Discussion
Topic: Partial Pressure in the Blood
Replies: 1
Views: 2458

Re: Partial Pressure in the Blood

Hi. I am not a biophysicist. But I assume that the contact between blood and gaz within the lungs is enough to make the equilibrium. I assume that the rupture of this equilibrium which happens when divers go back to the surface too quickly is related to gaz pressure at the lungs level.
by claudepa
Tue Aug 02, 2016 2:43 pm
Forum: Human Biology
Topic: A transcription factor promotes colorectal cancer growth
Replies: 1
Views: 2638

Cancer has been sometimes described as a disease of transcription factors. If you inhibit KLF12 in grafted tumors does the tumor shrinks ?