Transformation is a process in which bacteria take up new DNA released by dead cells and integrate it into their own genomes (se
e Chapter 9). In Streptococcus pneumoniae (which causes many cases of pneumonia, inner-ear infections, and meningitis), the ability to carry out transformation requires from 105 to 124 genes, collectively termed the com regulon. The com regulon is activated in response to a protein called competence-stimulating peptide (CSP), which is produced by the bacteria and exported into the surrounding medium. When enough CSP accumulates, it attaches to a receptor on the bacterial cell membrane, which then activates a regulator protein that stimulates the transcription of genes within the com regulon and sets in motion a series of reactions that ultimately result in transformation. Does the com regulon in S. pneumoniae exhibit positive or negative control
Increased levels of CSP induce the receptor to stimulate transcriptional activator functions, which allow gene expression to occur similar to what happens in positive inducible.
Luis was most trying to model the Earth's rotation. As you know the earth rotates around it's axis once every 24 hours and this is why we have different times in the day because the sun shines on different parts of the Earth as it rotates.
Luis used the flashlight as the sun and when he used the toothpick to spin the model of earth, the model would represent earth rotating around its axis.
