Chemistry of Life UEQ: How do the properties and structures
of materials determine their uses?
What determines the type and extent of a chemical reaction?
General
Chemistry
1. What is an atom?
2. What are
isotopes? What
makes an isotope
radioactive?
3. What are the
different types of
chemical bonds?
4. What is the
difference
between an acid
and a base?
Organic
Molecules
Water
1.
2.
Why is water
considered a
polar
molecule?
What
properties
result from
water’s
polarity?
1.
2.
3.
4.
What are
organic
polymers?
How are organic
polymers
made?
What is an
enzyme?
What role does
each play in
homeostasis?
Warm UP!
1. What is an atom?
2. What are isotopes? What makes an isotope radioactive?
3. What are the different types of chemical bonds?
Chemical Basis for
Life Chapter
6
Why do we need
Chemistry in Biology?
An understanding of biology requires a little
knowledge of chemistry, and an
understanding of chemistry requires a
little knowledge of mathematics. It is
important to know aspects of chemistry to
make biology come alive.
Modern biology overlaps with
chemistry in explaining the
structure and function of all
cellular processes at the molecular
level.
is anything that takes up space and has mass.
is made of atoms, which are the
smallest particles of an element
that still have all the properties of
an element.
Living organisms require about 20
elements (There are 92 elements in
nature and 19 made)
Oxygen, Carbon, Hydrogen,
and Nitrogen make up more than
95% of the human body.
The other elements include:
calcium, phosphorus, potassium,
sulfur, chlorine, sodium, magnesium
and many other trace elements
(meaning they have a very small
amount: iron, zinc, copper, etc)
 Smallest
 Made
amount of an element
up of 3 subatomic particles
◦ Neutrons (o) = neutral/no charge
◦ Protons (+) = positive charge
◦ Electrons (-) = negative charge
 Protons and Neutrons
are found in the
nucleus of the atom.
Electrons
are in
motion in the space
around the nucleus.
# E- = # P+
Why is this important and what
does it have to do with biology?
The positive charge from the Proton and the
Negative charge from the electron balance
out the charge of the atom.
These charges are what eventually aid in
forming combinations of atoms- or chemical
compounds …for example: water is made from
Hydrogen and Oxygen.
 Proton (+)
 Electron (-)
 Neutron (o)
The
electron is attracted to it’s opposite charge
(the proton +) so it remains in orbit around the
nucleus, but it plays “hard to get” by maintaining a
velocity that is fast enough that it’s never pulled into
the nucleus. The neutron is there to support the
nucleus but it never gets involved.
Isotopes
 …say an atom is missing a neutron or has an extra
neutron. That type of atom is called an isotope.
An atom is still the same element if it is missing an
electron. The same goes for isotopes. They are still
the same element. They are just a little different
from every other atom of the same element.
 If we look at the C-14 atom one more time we can
see that C-14 does not last forever. There is a point
where it loses those extra neutrons and becomes
C-12. That loss of the neutrons is called
radioactive decay. For carbon, the decay
happens in a couple of thousand years.
Chemical compounds are formed by
chemical bonds.
Atoms either lose electrons, gain
electrons or share their electrons in
order to form a bond with other atoms.
Atoms that lose or gain and electrons are
called ions
Gain electrons = negatively charged ion
Loose electrons = positively charged ion
The opposite charges attract and form a
bond called an ionic bond. These bonds
exchange electrons.
Click on diagram to
See animation
Example: Na+ClNa loses an electron
Cl gains an electron
Covalent bonds form when atoms
share their electrons instead of
exchanging them.
Example:
Click on covalent
Bond to see video
H and O form a covalent bond that creates
the molecule water.
Chemical Reactions: Acids and Bases
 Chemical reactions can only take place in the
right environment.
 Chemical reactions depend on the proper pH of
the environment within the organism.
 pH is the measure of how acidic or basic a
solution is.
pH
 Substances below a pH of 7 are considered acidic
 Substances above a pH of 7 are considered basic
 Substances around a pH of 7 are considered neutral
pH Activity!