New answers tagged molecular-genetics
Zabner et al (J. Biol. Chem., 1995, 270, 18997-19007) monitored the lipid-DNA complex formation and uptake which was found to be predominantly by endocytosis. Dot blot experiment shows that cells (50% population) took up 60% of the DNA. The DNA-protein complex was observed to be deposited in the perinuclear cytoplasm and formed a series of regularly packed ...
Allele is a variant form of a gene. How many alleles there are depends on number of copies of the gene and number of variants. In theory you can have 5 identical copies or single copy and single allele (Y-linked genes come to mind). Regulation is very complicated, I'll refer you to reading on recessiveness, dominance. Barr bodies also have to do with ...
A flower (or a person) has two alleles for a gene because it inherits one set of chromosomes from one parent and another, comparable, set of chromosomes from the other parent. Hence there are two copies of each gene, and so there are two alleles for each gene.
Either strand of DNA can be sense or antisense. SWBarnes2 posts that the "transcription machinery will only bind on the correct orientation" and that is indeed what determines which strand is sense. But note his important statement "the sequence is not correct on the anti-sense strand FOR A GIVEN GENE" (my emphasis). As you move from gene to gene, the ...
One of the reasons why DNA is double stranded--this means DNA has sense and antisense strands--is to make a copy. During transcription, RNAs are transcribed referring to anti-sense strand sequences--making base pairs with anti-sense strand. In other words, the sense strand does not do anything during transcription.
The short answer is the transcription machinery will only bind on the correct orientation. The binding of proteins and such to the promoter DNA strand is determined by the sequence of the DNA, the sequence is not correct on the anti-sense strand for a given gene.
It could be difficult for RNApol to access genes inactivated because inactivated genes are often tightly packed by chromatin. Many genes have enhancer elements(specific DNA sequences) as well as TATA, and transcriptional enhancers, which are proteins, would recognize enhancer elements in a sequence dependent manner and loosen chromatin structure to make ...
There is no requirement that DNA should have a whole number of base pairs per turn. As a thought experiment, say you have a helix of dsDNA with 10 base pairs that completes one helical turn (ie it has 10 bp/turn). Now, twist that DNA along its axis so that it completes 1.5 turns. There is still only 10 bp and thus 6.67 bp/turn (which you should notice is a ...
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