Please answer all four questions thank you

Introduction Charges are ubiquitous in living systems. Large moleculesproteins in particularare often phosphorylated and thus carry a net charge. These charges generate electric elds, exerting attractive forces on other molecules, and playing a role in the intricate balance of forces and movements within cells. These effects are crucial for understanding biological systems at the cellular level. To investigate this we will be using Zuni-diameter glass microbeads in uid. When the glass beads are submerged in water, they become charged: the silicate (8102) have surface groups of SiOH. When immersed in water, the hydrogen nucleus breaks free, leaving an SiO behind. Thus the surface of the glass beads becomes negatively chargedeach bead carries a tiny charge on the order of afemto-Coulomb (fC - 1045(3). If a salt (like NaCl) is added to the uid, it will dissolve. These free cations (or anions depending on the solution) will attach themselves to the beads, negating their charge; this is called charge screening. The more ions that are available in the uid, the greater the charge screening effect will be; thus the net negative charge on the beads will decrease as ion concentration increases. To investigate this charge screening effect, we will first need to determine how charged the beads are in DI water, and then compare that charge to the effective charge as seen in concentrations of saline solution. We will do this using the same basic process driving electrophoresis: we will create an electric eld in the uid, causing an electric force to move the charged beads through the uid