BIOL 1107 Chapter Notes - Chapter 2: Unpaired Electron, Electron Shell, Radionuclide
Document Summary
Chemical evolution- theory that the inputs of energy led to the formation of increasingly complex carbon-containing substances, culminating in a molecule that would replicate itself. When the replication happens, there is a switch from chemical to biological evolution. As original molecule multiplied, evolution by natural selection happened. The descendant of the original became metabolically active and acquired a membrane. 2. 1: atoms, ions, and molecules: the building blocks of chemical evolution. H, c, o, and n make up 96% matter found in organisms. Every element but h has more than 1 neutron in its nucleus. Protons = +, electrons = -, neutrons = +- (neutral) Sum of protons and neutrons = mass number. Biologists use special unit called dalton (da) because the numbers involved are so small (mass). Isotopes- fo(cid:396)(cid:373)s of a(cid:374) ele(cid:373)e(cid:374)t (cid:449)ith diffe(cid:396)e(cid:374)t (cid:374)u(cid:373)(cid:271)e(cid:396) of (cid:374)eut(cid:396)o(cid:374)s, (cid:862)e(cid:395)ual-pla(cid:272)es(cid:863) of neutrons. Isotopes of same element have different masses because they have different number.
