All living and nonliving things are made of molecules. Molecules are made up of atoms So we must...
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Transcript of All living and nonliving things are made of molecules. Molecules are made up of atoms So we must...
CHEMISTRY OF LIFE
MOLECULES: All living and nonliving things are made
of molecules. Molecules are made up of atoms So we must understand atoms to
understand the chemistry of life
MATTER Matter-
Anything that takes up space and has massComposed of chemical elements
Human Recipe:
COMPOUNDS Compounds- substance of two or more
elements combined in a fixed ratio
Sodium (Na) Chlorine(Cl) Table Salt (NaCl)
+ =
ATOM- SMALLEST UNIT OF MATTER If an atom loses or
gains an electron it becomes an Ion.
Electron arrangement gives the atom its chemical properties
ATOMS Atoms with the same amount of protons
and electrons, but a different amount of neutrons are called Isotopes.
COVALENT & IONIC BONDING
•Electrons are shared among atoms•Molecules are held together by these •Can be polar or non-polar
•Electrons are transferred •Holds Ions together
COVALENT BONDING
Polar Non- Polar
Unequal charges among atoms
Charges are kept equal among atoms
(–) (–)
O
HH
(+) (+)
Hydrogen bonds are weak bonds important in the chemistry of life
http://www.youtube.com/watch?v=CT4pURpXkbY
Hydrogen bond
PROPERTIES OF WATER Adhesion-
– water can stick to other molecules Causes the
meniscus in a test tube
Cohesion- water sticks to
other water molecules
Because of hydrogen bonding
Causes high surface tension- difficulty to break the surface of a liquid
EVAPORATIVE COOLING
Water is highly resistant to heatHeat is absorbed when bonds form Heat is released when bonds break
Evaporative Cooling- water molecules of high energy leave Ex: Sweating
Liquid waterHydrogen bonds
constantly break and re-form
IceHydrogen bonds
are stable
Hydrogen bond
Ice is less dense than liquid water
Ion insolution
Saltcrystal
Water is the solvent of life
solution = solvent (dissolving agent) + solute
Universal solvent
http://www.youtube.com/watch?v=QH1yphfgfFI
Acidic solution
pH scale
Battery acid
0
1
2
3
4
5
Lemon juice, gastric juice
Grapefruit juice, soft drink,vinegar, beer
Tomato juice
Rain water
Human urine
Saliva
Pure water
6
7
Human blood,tears
Seawater
8
9
10
11
12
13
Milk of magnesia
Household ammonia
Household bleach
Oven cleaner
Neutral solution
Basic solution
NEUTRAL[H+]=OH–]
Incre
asin
gly
AC
IDIC
(Hig
her
con
cen
trati
on
of
H+)
14
Incre
asin
gly
BA
SIC
(Low
er
con
cen
trati
on
of
H+)
The chemistry of life is sensitive to acidic and basic condition
s
Acidic solution Neutral solution Basic solution
BIOLOGY AND SOCIETYOne of the authors of your text once overheard the following:
“It’s paranoid and ignorant to worry about industry or agriculture contaminating the environment with their chemical wastes. After all, this stuff is just made of the same atoms that were already present in our environment anyway.”
What do you think of this statement? Why?
Disagree Agree
Strongly A B C D E Strongly
BIOLOGY AND SOCIETYToo little iodine in the diet can lead to goiter—the condition afflicting this person. Goiter is not common in developing countries because iodine is added to salt and other foods.
Do you think that adding trace elements to food items is good public policy? Why?
Disagree Agree
Strongly A B C D E Strongly