11.   He found that proteins in the cell nucleus, called histones, were responsible for turning genes off and that plant hormones interacted with the histones.

12.   In Prokaryotes, the chromosomes are not confined to a cell nucleus but float freely in the cell.

13.   It is where proteins fold, charged ions move through cell membranes and messenger molecules read DNA instructions in the cell nucleus.

14.   Normally, this protein is successfully produced and does its work in the cell nucleus, a sack at the center of a cell that contains the genetic material.

15.   On present evidence therapy would require hundreds of unfertilized human egg cells, or oocytes, to successfully reprogram one skin cell nucleus.

16.   Once this damage occurs, the cell nucleus releases repair enzymes that snip out the damaged DNA fragments, Dr. Gilchrest said.

17.   Simple bacteria have no cell nuclei.

18.   Some of the problems involved damage to the chromosomes, the rod-shaped bodies in the cell nucleus that carry the genes.

19.   Such analogues would stimulate the receptor or parts of the pathway that delivers the leptin signal to the cell nucleus, he said.

20.   The same process in people may require a human egg cell to reprogram the skin cell nucleus.