Chromatin Structure: Beads on a string
Chromatin is composed of DNA and proteins.
-Beads on a String: The DNA is negatively charged and loops two times around the postively charged proteins (called Histones: H2A, H2B, H3, and H4). There are 2 of each of these histones (to make an octamer). Another protein (H1) connects the octamer beads to each other.
Heterochromatin: Condensed and inactive (no transcription).
Euchromatin: Less condensed and active (transcription happening on it).