Which atom prefers to hold onto its electrons more tightly? A. Fluorine B. Tungsten C. Cesium
This is a question probing at the concept of electronegativity and trends in the periodic table. The correct answer is A! Fluorine holds onto its electrons more tightly because it is only one electron away from having a stable octet. It as two options to become stable: 1. Give up seven electrons or take one. It would much rather (due to energetic favorability) gain one electron to create a stable 8 valence electron shell.
What is the electron configuration of P?
You are responsible for creating an inducible trans-gene system to ablate the immune cells of zebrafish, and you are told that you will be using the nitroreductase mediated ablation method recently described in a Nature Communications article. Before you begin you want to plan out the experiment, you want to make sure that the NTR gene is only expressed in the immune cells. How will you ensure that the NTR gene is only expressed in the immune cells and what are some drawbacks to this method?
First, obtain specificity in a trans-gene system such as the NTR mediated ablation system, you must find a specific promotor. However, there is not one specific promotor that is expressed in only immune cells, so you will have to create multiple constructs to attack each cell line lineage. Second, even if a promotor is specific to the immune system, you must make sure that its expression is sufficiently strong. In this case, you would want strong expression to express a lot of the NTR protein to reduce the amount of drug that you needed to add to ablate the immune system.