Question

SAT Chromosome has
A) More heterochromatin part
B) More G=C part
C) More non-histone protein
D) More amount of lipid.

Answer 1

Satellite chromosomes derive their name from the fact that they look like globular sections away from the main chromosome, but close examination shows that they are bound to the chromosome by a compacted region.

Complete answer:
SAT Chromosomes are satellite chromosomes. The term was given as the head of the chromosome is separated from the main body by a secondary contrition making it look like these are floating away. It’s called secondary because the region of the chromosome attached to the centromere is known as the primary constriction. Such tightly packed DNA is known as heterochromatin; therefore the SAT chromosome has more heterochromatin parts.

G=C regions are areas with greater bonding between the two strands of DNA in the helix, as there are triple bonds between the Guanine and Cytosine bases. Satellite chromosomes have repetitive sequences of DNA, and there a relative similar amount of each base.

The SAT chromosome does not contain more of non-histone protein, though these proteins are important in assisting in nucleolar organisation. Lipids are also not there in greater amounts in SAT chromosomes.

This secondary constriction contains specialised DNA forming the NOR or nucleolar organiser region. The NOR contains many copies of the genes for 18S and 28S ribosomal proteins, essential for the production of ribosomal RNA. The region is also essential for the formation of the nucleolus in a new cell after cell division is complete.

Note: The full form of SAT is Sine Acido Thymonucleinico and these are present in all types of satellite chromosomes. These remain attached to the nucleolus during interphase.