Download Document

By: Mrs. Bailey
Biology Content Standards
1. The Chemistry of Life
Broad Concept: Chemical elements form organic molecules
that interact to perform the basic functions of life.
1.1 Recognize that biological organisms are composed primarily
of very few elements. The six most common are C, H, N, O, P, S.
1.2 Describe the basic molecular structures and primary
functions of the four major categories of organic molecules
(carbohydrates, lipids, proteins, and nucleic acids).
1.3 Explain the role of enzymes as catalysts that lower the
activation energy of biochemical reactions. Identify factors,
such as pH and temperature, which have an effect on
enzymes.
Atoms are the smallest particle
into which an element can be
divided.
Isotopes differ from each other
in the number of neutrons, not in
the number of protons.
Ionic bonds are formed when
atoms become ions by gaining or
losing electrons.
Covalent bonds form when
atoms share electrons.
A.
Water covers more than 75% of the Earth’s surface.
It is the most abundant compound in nearly all living things!
B.
Water is able to dissolve 1000’s of substances because it is
POLAR - slightly charged on each end.
This results in the
property of
COHESION
Water is “sticky”
Cohesion
Surface Tension
CAPILLARITY
ADHESION
Attraction of water to solids
Water is the “universal” solvent !
MIXTURE
- a substance made up of 2 or more
elements or compounds that are mixed together but
not chemically combined.
Living things are in part
composed of mixtures
involving water.
MIXTURE
Solution
Suspension
A mixture in which one or
more substances are
evenly spread out in
another substance
A mixture of water and
non-dissolved material.
Examples:
Salt water,
sugar water,
plasma
Examples:
Dirt and water,
Italian salad
dressing, blood
Solution = Solute + Solvent
Dissolve
the solute
in the
solvent!
Acid - compound that releases hydrogen ions (H )
+
into solution.
pH: 1-6
Citric acid
pH = 2
HCl
pH = 1
Ascorbic acid
pH = 3
Base - compound that releases hydroxide ions (OH )
-
into solution.
pH: 8-14
pH = 11
pH = 9
pH scale
is from
0-14
A buffer is a solution that can
maintain a nearly constant pH
when diluted, or
when strong
acids or bases
are added.
A. INORGANIC COMPOUNDS
Compounds that do not contain carbon
Examples: Water, Minerals (Calcium phosphate/ bone)
Exception is CO2
B. ORGANIC COMPOUNDS
Compounds that
DO contain carbon
(except CO2)
Examples: Sugars, Fats,
Proteins, DNA
6 Most Common Elements in Organic Molecules! I definitely
need to
know this!
is special!
•  Forms covalent bonds that are strong and stable.
•  Can form 4 single covalent bonds.
•  Can also form double bonds, triple bonds, chains,
and rings!
Remember:
A covalent bond is formed by
2 shared electrons!
C.
Poly = many
mer = unit
à
Polymer = many units.
A polymer has a repeating structure, usually based on a carbon
backbone. The repeating structure results in large chainlike
molecules.
a “monomer”
a “polymer”
A macromolecule
is a giant polymer!
4 Major Categories of Organic Compounds
•  Carbohydrates
•  Lipids
•  Proteins
•  Nucleic Acids
•  General formula is
C(H2O)n
•  Sugars, starches,
cellulose
•  High Energy!
Mono-saccharide
Contains 1 saccharide molecule
Di-saccharide
Contains 2 saccharide molecules
Poly-saccharide
Contains many saccharide molecule
•  Glucose
the sugar green plants produce
•  Galactose
found in milk
•  Fructose
found in fruits (sweetest)
C6H12O6
C6H12O6
C6H12O6
C6H12O6
R is a carbon group,
such as -CH3
Glucose
Fructose
6
5
1
4
3
2
OH is
down …
α-
Glucose
β-
OH is
up …
•  Maltose
Malt sugar (glucose + glucose)
•  Lactose
Milk sugar (glucose + galactose)
•  Sucrose
Common table sugar (glucose +fructose)
NOTE: A molecule of water
is lost!
Maltose
+
Lactose
NOTE: A molecule of water is lost!
Sucrose
Largest carbohydrate (may consist of 1000s of monosaccharides)
•  Starch
Plants store excess sugar in this form
inside of leucoplasts.
•  Glycogen
Animals store excess sugar in this form
… liver and muscles.
•  Cellulose
Gives strength and rigidity to plant cell
walls.
All are
polymers
of glucose!
Starch grains in a bean embryo. Why so many?
Glycogen is stored in liver and muscle
cells!
Muscle cells
Liver cells
Cellulose
Starch … made up of α-glucose
Cellulose … made up of β-glucose.
Toughness is due to the arrangement of glucose units in the polymer
chain and the hydrogen-bonding between neighboring chains.
•  The joining of 2 or more monomers to
form a larger polymer.
•  When the bond is complete, a molecule
of water is released from the 2 monomers.
EXAMPLE:
The joining of glucose and fructose to form sucrose.
•  A polymer is split apart to again form
monomers.
•  A water molecule is taken in by the
chemical reaction.
EXAMPLE:
The splitting of sucrose into glucose and fructose.
or …
maltose
into
glucose
and
glucose!
•  Fats, oils, and waxes.
•  Lipids are compounds
made up of C, H, and
O, but often P and N.
•  Many lipids are formed by
the attachment of two or
three fatty acids to glycerol (an organic alcohol).
fatty acid
fatty acid
glycerol
fatty acid
Because of the kinks in the hydrocarbon tails, unsaturated fats can’t
pack as closely together, making them liquid at room temperature.
Lipids:
3 major roles in living things
1.  Store energy
2.  Form biological membranes.
3.  Some hormones are lipids.
Seal pup has blubber.
Unlike other
organic
compounds,
lipids do not
Oil
dissolve in
water!
Why would that
be very important
in living things?
Water
Types of Lipids (based on structure)
•  Triglyceride
- 3 fatty acids + glycerol
•  Phospholipid
- 2 fatty acids + glycerol
•  Wax - long fatty acid chain + a long alcohol chain.
•  Steroid - composed of 4 carbon rings
Found in substances as varied as hormones, nerve
tissue, toad venoms, and plant poisons.
Cholesterol To be specific, it is a sterol or a steroid with an –OH group
•  Cholesterol is an important part of
many cells such as nerve cells.
•  However, excessive
cholesterol in the diet
is a risk factor for
heart disease.
Here we go again …
•  Organic compounds composed mainly of C, H, O, and N.
•  Proteins are polymers of
together by peptide
AMINO ACIDS , joined
bonds.
•  All amino acids have a similar chemical structure, but
differ in a region of the molecule known as an R group.
(Variable group)
(Amino group)
(Carboxyl group)
The amino acid,
phenylalanine, is found in
the sweetener aspartame.
Infants born with w/PKU
cannot break down
phenylalanine. The buildup
can retard normal brain
development.
Here we go again …
PROTEINS
2°
1°
3°
4°
Proteins have MANY ROLES! •  Help carry out chemical reactions by serving as enzymes.
•  Pump small molecules in/out of cells by serving as
permeases.
•  Serve as chemical messengers called hormones.
•  Used in forming disease–fighting antibodies.
•  Provides energy if carbohydrate and fat are in short supply.
•  Play a structural role – cytoskeleton - The skin and
muscles of animals are made mostly of proteins.
•  Biological catalysts (speed up reactions by lowering
activation energy , but remain themselves unaffected)
•  Most enzymes are proteins.
•  Active Site - a special place on the
enzyme where chemical bonds form
between enzyme and substrate.
•  Work within an optimal range of pH
and temperature.
Enzymes lower
activation energy (EA)!
Substrate
Substrate
Products
Substrates
Product
Temperature increase
speeds up enzyme controlled reactions,
but only to a point.
When heated too
much, enzymes (since
they are proteins
dependent on their
shape) become
denatured.
Changes in pH will also denature the enzyme by changing
the shape of the enzyme. Enzymes are also adapted to operate at a
specific pH or pH range.
(mouth)
(stomach)
(kidney)
•  Very large and complex organic molecules that
store important information in the cell.
•  Polymers of
nucleotides.
•  There are 2 Basic Kinds:
DNA and RNA.
1.
2.
4.
3.
Biology Content Standards
1. The Chemistry of Life
Broad Concept:
Chemical elements form organic molecules that
interact to perform the basic functions of life.
1.1 Recognize that biological organisms are composed primarily
of very few elements. The six most common are C, H, N, O, P, S.
1.2 Describe the basic molecular structures and primary
functions of the four major categories of organic molecules
(carbohydrates, lipids, proteins, and nucleic acids).
1.3 Explain the role of enzymes as catalysts that lower the
activation energy of biochemical reactions. Identify factors,
such as pH and temperature, which have an effect on
enzymes.