Answer:
False
Explanation:
The histones that are more positively charged, tight hardly to negatively charged DNA. So, enzymes, such as acetyltransferases, that reduce the positive charge of histones promote transcription.
Chromatin structure and its modifications can change the package of the DNA and consequently, alter the gene expression. The most common modifications of the chromatin are covalent modifications such as acetylation/deacetylation (by acetyltransferases and eacetylases), methylation (by methyltransferases), and phosphorylation (by kinases). This is the way of gene expression regulation.
The effects of modifications are different, for example methylation promotes condensation of the chromatin and as a consequence, prevents binding of transcription factors to the DNA (transcription is repressed).
Acetylation loosens the association between nucleosomes and DNA (because it neutralizes the positive charge of histones) and consequently promotes transcription. Deacetylation is a process opposite to acetylation.
Explanation:
cells which can divide an unlimited number of times by mitosis
Borders are still guarded zealously and fought for - via wars when required and when not required in equal measure. I see nations fighting
over water that preciously scarce resource of the future. I see that terrorists still abound - the Osama Bin Laden types still roam the Earth terrorizing countries and peoples with newer weapons and newer methods of instilling terror. I see that the United States is no longer the sole superpower of the world -- the most powerful country on Earth. I see the most powerful countries dominating the world as being China, India, Brazil and Russia in that order. I see that China and India have become the equivalent of the US and the erstwhile Soviet Union - fighting another Cold War between them and competing for resources and influence around the world.
The easiest example is of Pentadactyl limbs. This is the 5 bone structure of the 'arm' of different animals being similar, contributing to the explanation of common ancestors. Animals that have this are whales, horses, dogs, cows, birds and even humans. We each share the same five bones in similar places but with some of them changed to suit certain functions ie birds are more spread to support flying, while humans are made for throwing, picking up and holding things.
Coronary artery.....are the arteries that provide blood to the wall of heart !
