DNA replication and transcription
The DNA instruction manual stays in the nucleus, held in by a double layer
of membrane. When the cell divides, all of the DNA in the nucleus replicates
- copies itself - so that both new cells have the whole instruction manual.
When the cell needs to make a protein, chemical signals tell the DNA which
page to use. Once on the right page, or area along the DNA's length, the
top strand of DNA serves as a stencil for a messenger RNA (mRNA).
A single-stranded copy of the DNA page forms. Upon release from its parent DNA page, it brushes off some excess toner and gets ready for the trip out into the cytoplasm. Its mission: to deliver its message to the nearest protein factory.
Written and webbed by Jolane Abrams
Corrections and comments to jka@midgard.net
