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Unformatted text preview: Biological Chemistry The universe is composed of
energy and matter. Life,
and Everything Matter is in the form of chemicals.
• Chemicals are constructed from atoms.
• Different types of matter, i.e., different elements, have
different atoms. The Atom
• A single unit of matter
• Composed of three types of subatomic particles
– Neutrons (no): mass = 1 atomic mass unit
no electrical charge (neutral)
– Protons (p+):
mass = 1 atomic mass unit
positive electrical charge (+1)
– Electrons (e–): mass is trivial
negative electrical charge (–1) Atomic Number
• A chemical reaction is the interaction of electrons from
• The number, distribution and activity of electrons around
an atom’s nucleus is determined by the number of protons
in that nucleus. • At the beginning of the universe, energy was converted
into matter. Big Bang!
• Only in rare circumstances, like inside stars and atomic
blasts, matter is converted back into energy. m
E= c •Energy is often converted from one form into another:
(e.g., light energy into chemical energy; chemical enegy into
kinetic energy; kinetic energy into heat energy; etc.) but it is neither created nor destroyed.
•But matter, with rare exceptions, stays the same type of
matter. Atomic Structure
• Neutrons and protons
form the nucleus
• Atomic Mass
= number of
protons and neutrons
• Electrons orbit
around the nucleus
[p+] [n °] [e-] Partial Periodic Table
atomic number •
.. The “chemical identity” (type of element) for any atom is
determined by the number of protons in its nucleus!
# of p+ = the Atomic Number for that atom. E.g.: Any atom that has 6 p + in its nucleus (atomic number = 6)
is defined as carbon , no matter how many e - or n ° it has! Heyer 1 Biological Chemistry Isotopes 96% of body mass is composed of
four different elements
Table 2.1 • Oxygen (65%)
• Carbon (18%)
• Hydrogen (10%)
• Atoms of the same element (i.e., same atomic number) but
with differing numbers of neutrons, ha...
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This note was uploaded on 09/02/2011 for the course BIOL 6B taught by Professor Heyer during the Spring '10 term at DeAnza College.
- Spring '10
- molecular biology