CHROMOSOME STRUCTURE

=Chromosome Structure= [image:http://i.imgur.com/EyvEbzEl.png] DNA is wrapped around special proteins called '''histones'''. These histones can be modified by adding or removing certain chemical groups. These modifications affect histone packing and this plays an important role in regulating which genes are expressed. Together, the DNA and histone proteins form a coil known as a '''chromatin fibre'''. The chromatin fibre is looped into a flower pattern that is repeated many times. The resulting structure resembles a bottle brush (without a handle) and this is what makes up each chromatid (each of the two copies of DNA that make up the replicated chromosome).