The nitrite ion (NO2 2) in soil is oxidized to nitrate ion (NO3 2) by the bacteria Nitrobacter agilis in the presence of oxygen. The half-reduction reactions are NO2 3 1 2H1 1 2e2 NO2 2 1 H2O E 5 0.42 V O2 1 4H1 1 4e2 2H2O E 5 1.23 V Calculate the yield of ATP synthesis per mole of nitrite oxidized. (Hint: See Section 17.7.)
BLY 121 Chapter 2 Notes August 23, 2016 Atomic Theory Socrates-Born in Ancient Greece ~500 BC All matter is made up of tiny invisible particles named “atoms” Matter has mass and occupies space (Composed of chemical elements) “type” of matter depends on atomic structure Atom: smallest unit of matter which retains the physical and chemical properties of an element. Consists of protons, neutrons, and electrons. Atomic Structure (Niels Bohr-Quantum Physics): Nucleus composed of protons and neutrons and surrounded by orbiting electrons. Protons and neutrons have roughly the same mass (1 Dalton) Electron’s weight is negligible. Atomic number= # of protons Atomic mass/weight= mass of protons and neutrons combined (i.e. Carbon’s atomic number is 6 and atomic mass is 12.01, so the number of electrons is 6.) Isotopes: atoms of an element that contain a different number of neutrons (i.e Carbon-12, Carbon-13, and Carbon-14) *Note: Isotopes (e.g. Carbon-14) are unstable and decay at a constant rate. (disappear) Example: After death, Carbon-14 atoms decay at a constant rate (half- life=amount of time for 50% of atoms to decay) Carbon Dating: Measures ratio of Carbon-14 (decreasing) to Carbon-12 (stays the same) in a fossil and compares to ratio in living organisms (which is constant). (Tells how long the organism has been around, living, or dead) Radiometric Dating: Other isotopes have much longer half lives After mineralization, radioactive atoms begin to decay Provides evidence for a very old earth. Approximately 4.
