All life on earth is based on one of many two-polymer systems, each made up of a protein and a nucleic acid. in a cell, these polymers are, for the most part, charge-balanced, with the nucleic acid in any pair carrying a negative charge and the protein carrying an equal amount of positive charge. consider a distribution of eight of these polymers, where the eight proteins sit together near the center of the cell and the nucleic acids are spread out along the circumference of a circle with the radius equal to one-quarter of the cell diameter, centered on the proteins. part a: - if seven of the eight nucleic acids are at ? /2, 3? /4, ? , 5? /4, 3? /2, 7? /4, and 2? rad, where on the circle must you place the eighth acid to give the system a balanced charge distribution? (hint: begin by making a sketch.)

if seven of the eight nucleic acids are at , , , , , , and , where on the circle must you place the eighth acid to give the system a balanced charge distribution? (hint: begin by making a sketch.)

1) at 3? rad
2) at ? /4 rad
3) at ? /8 rad
4) at ? /3 rad

For a family dinner, jose’s mom baked a loaf of bread. during the meal, his grandmother commented, “this bread is so dense! ” what do you think his grandmother meant by the word dense? you have some ideas regarding density already, but this experiment will enrich your understanding of the relationship between mass, volume and the density of objects. when making measurements in this experiment we will be using si units, the international system of units. the purpose of using si units is to have the ability to communicate and compare data results with other experiments without having to make conversions. measurement symbol si unit length m meter mass kg kilogram volume l liters density kg/l kilograms per liter any calculations that are performed during this experiment will ultimately be reported in scientific notation. recall that scientific notation is extremely important when we have data that is extremely small or large. scientists rely on a standard form of communication to quickly make hypotheses and judgements based on data. what is the density of block a? a0kg/l what is the density of block b? a1kg/l what is the density of block c? a2kg/l what is the density of block d? a3kg/l what is the density of block e? a4kg/l which block is the densest? a5