*loosely packed - form nucleosomes: like beads on a string

*region of ACTIVELY transcribed DNA

*tightly packed

*inactive (genes repressed, not being transcribed)

*found in eukaryotes only

testosterone

*intracellular receptor

-passes through the membrane

-binds to a receptor in the cytoplasm

-complex enters the nucleus, triggers a reaction

-cell responds

phosphorylation cascade

*multi-step signal pathway

*series of activations that eventually lead to a cellular response.

*involves proteins that activate and deactivate other proteins in a "cascade" like reaction that eventually leads to the response.

constitutive expression

always on

transcription factors

bind to control elements

modulate the amount of transcription that will take place by influencing the binding of RNA polymerase

control elements

enhancers

distal and proximal control elements