[Juan Negrín (1892-1956) and experimental investigation at the Laboratorio de Fisiología de la Junta para Ampliación...

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression and precisely regulates the production of proteins within the cell. In contrast, the DNA inside the mitochondria and chloroplasts only carries out functions that are specific to those organelles.Arrangement of DNA within the NucleusThe regulation of gene expression inside the nucleus is dependent on many factors, including the DNA structure.

Many human characteristics, like height, are shaped by both nature—in other words, by our genes—and by nurture, or our environment. For example, chronic stress during childhood inhibits the production of growth hormones and consequently reduces bone growth and height. Scientists estimate that 70-90% of variation in height is due to genetic differences among individuals, and 10-30% of variation in height is due to differences in the environments that individuals experience, such as differences...