Download 2-2 Properties of Water

2-2 Properties of Water
Key Concepts: Why are water
molecules polar?
What are acidic solutions?
What are basic solutions?
I. The Water Molecule
A. A water molecule is polar
because there is uneven sharing
of electrons between the oxygen
and hydrogen atoms.
B. Hydrogen bonds form when
water molecules are attracted to
one another.
C. Cohesion – attraction between
molecules of the same substance.
D. Adhesion – attraction between
molecules of different substances.
II. Solutions and Suspensions
A. Mixture – material composed of 2
or more elements or compounds
that are physically mixed together
but not chemically combined.
B. Solutions – mixture of 2 or more
substances in which the
molecules of the substance are
evenly distributed.
1. solute – the substance that is
dissolved.
2. solvent – the substance in
which the solute dissolved.
C. Suspension – mixture of water
and nondissolved materials.
III. Acids, Bases, and pH
A. pH scale – measurement system
used to indicate the concentration
of hydrogen ions (H+) in solution;
ranges from 0 to 14
B. Acid – any compound that forms
H+ ions in solution
C. Acid solutions contain higher
concentrations of H+ ions than
pure water and have pH values
below 7.
D. Base – a compound that
produces hydroxide (OH-) ions in
solution
E. Basic, or alkaline, solutions
contain lower concentrations of H+
ions that pure water and have pH
values above 7.
F. Buffers – weak acids or bases tha
can react with strong acids or
bases to prevent sharp, sudden
changes in pH.
G. Controlling pH is important in
maintaining homeostasis in the
human body.
2-3 Carbon Compounds
Key Concepts: What are the
functions of each group of organic
compounds?
I. The Chemistry of Carbon
A. Carbon has 4 valence electrons
and can form 4 covalent bonds
with other atoms.
B. Carbon atoms can bond with
other carbon atoms, forming
chains or rings with single,
double, or triple bonds.
II. Macromolecules
A. Macromolecules are giant
molecules formed by joining small
molecules together to make large
compounds.
B. Monomers – small units that can
join together with other small units
to form polymers
C. Polymers – large compounds
formed from combinations of
many monomers
D. Four groups of organic
compounds found in living things
are carbohydrates, lipids, nucleic
acids, and proteins.
III. Carbohydrates
A. Carbohydrate – compound made
up of carbon, hydrogen, and
oxygen atoms, usually in a 1:2:1
ratio
B. Living things use carbohydrates
as their main source of energy.
Plants and some animals also use
carbohydrates for structural
purposes.
C. Sugars and starches are
examples of carbohydrates.
D. Monosaccharide – single sugar
molecule
E. Monosaccharides are the
monomers of carbohydrates.
F. Polysaccharide – large
macromolecule formed from
monosaccharides
G. Animals store excess sugar as
glycogen.
H. Plants store excess sugar as
plant starch.
I. Plants also make cellulose, a fiber
that gives plants their strength
and rigidity. Cellulose is the most
abundant organic compound
found on the Earth.
IV. Lipids
A. Lipid – macromolecule made
mainly from carbon, hydrogen,
and oxygen atoms not in a 1:2:1
ratio
B. Lipids include fats, oils, waxes,
and steroids.
C. Lipids can be used to store
energy. Some lipids are
important parts of biological
membranes (ex. cholesterol) and
waterproof coverings.
D. Fatty acids are the monomers
of all lipids. Many lipids are
formed when a glycerol molecule
combines with 3 fatty acids.
E. In saturated fatty acids, the
carbon atoms are joined by single
bonds giving the compound the
highest possible number of
hydrogen atoms.
F. If there is at least one double or
triple bond in the lipid, it is
unsaturated because it does not
contain the most possible
hydrogen atoms.
G. Lipids whose fatty acids
contain more than one double or
triple bond are said to be
polyunsaturated.
V. Nucleic Acids
A. Nucleic acids – macromolecules
containing carbon, hydrogen,
oxygen, nitrogen, and phosphorus
B. Nucleic acids are polymers
assembled from individual
monomers called nucleotides. An
important nucleotide is ATP, the
direct source of energy used by
cells.
C. Nucleotides consist of 3 parts:
1. a 5-carbon sugar
2. a phosphate group, and
3. a nitrogenous base
D. Nucleic acids store (ex. DNA)
and transmit (ex. RNA) hereditary,
or genetic information.
E. Two types of nucleic acids:
1. RNA – ribonucleic acid
(contains the sugar ribose) and
2. DNA – deoxyribonucleic acid
(contains the sugar
deoxyribose)
VI. Proteins
A. Proteins – macromolecules that
contain carbon, hydrogen,
oxygen, and nitrogen
B. Proteins are polymers of
molecules called amino acids.
C. Amino acids are composed of
3 parts: an amino group (-NH2)
on one end, a carboxyl group (COOH) on the other end, and a
side chain called an R-group.
D. There are over 20 different Rgroups so there are over 20
different amino acids.
E. The order of the amino acids
deterimes the basic structure of
all proteins, ths proteis are the
most diversitifed of all
macromolelcules, as well as the
most abundant compounds ofund
in living things.
F. Some proteins control the rate of
reactions (ex. enzymes) and
regulate cell processes (ex.
hormones). Some are used to
form bones and muscles (ex.
actin & myosin.) Others transport
substances into or out of cells or
throughout the body (ex.
hemoglobin), or help to fight
disease (ex. antibodies).
G. Proteins can have up to 4
levels of organization, which
determine the shape of the
protein, therefore they are quiet
large and complex.
2-4 Chemical Reactions and
Enzymes
Key Concepts: What happens to
chemical bonds during chemical
reactions?
How do energy changes
affect whether a chemical reaction
will
occur?
Why are enzymes
important to living things?
I. Chemical Reactions
A. Chemical reaction – process that
changes one set of chemicals into
another set of chemicals
B. Reactants – elements or
compounds that enter into a
chemical reaction
C. Products – the elements or
compounds produced by a
chemical reaction
D. Chemical reactions always
involve the breaking of bonds in
reactants and the formation of
new bonds in products.
II. Energy in Reactions
A. Energy is released or absorbed
when chemical bonds are broken
or formed.
B. Chemical reactions that release
energy often occur
spontaneously. Chemical
reactions that absorb energy will
not occur without a source of
energy.
C. Activation energy – energy
needed to get a reaction started.
III. Enzymes
A. Catalyst – a substance that
speeds up the rate of a chemical
reaction
B. Enzyme - protein that acts as a
biological catalyst
C. Cells use enzymes to speed up
chemical reactions that take place
in cells.
D. Enzymes act by lowering the
activation energy.
IV. Enzyme Action
A. Enzymes provide a site where
reactants can be brought together
to react.
B. Substrate – reactant of an
enzyme-catalyzed reaction
C. Substrates bind to a site on an
enzyme called the active site,
fitting together like a lock and key.
D. Once the enzyme-substrate
complex is formed, the enzyme
helps convert substrate into
product.
E. Enzymes in the human body
work best at body temperature,
37°C.
F. Enzymes play essential roles in
regulating chemical pathways,
making materials that cells need,
releasing energy, and transferring
information.