Terms to be familiar with before you start to solve the test: chromatin, nucleases, sucrose density gradient centrifugation, melting point, gel electrophoresis, ethidium bromide, autoradiography, Southern blotting, Northern blotting, Sanger sequencing, restriction endonucleases, exonucleases, linker DNA, chloroform extraction, nucleosomes, nucleosomal histones, histone H1, nonhistone proteins, laminin, lamin, solenoid, DNA methylation, CpG islands, histone acetylation, centromere, histone octamers, "beads-on-a-string'', euchromatin, heterochromatin.