Transcript chapter 2 biochemistry

Chemistry in Biology
Elements in the Human Body
(CHON 96%)
We’ve got chemistry…(which is the study of
matter)
 The atom is the basic unit of matter.
(building block of matter)
 Atoms consist of subatomic particles
Protons (+ charge)
Neutrons ( no charge)
Electrons (- charge)
 Protons & neutrons are found in the nucleus.
 Electrons orbit the nucleus.
 Protons & neutrons have about the same mass, and
electrons are much less (1/1840 the mass of p & n)
Using the Periodic Table
to calculate:
 Protons = atomic number
 Electrons = atomic number (neutral atom,
not in an ion)
 Remember Protons are positive and
Electrons are negative so they are equal!
 Neutrons = atomic MASS – atomic
number
 ELEMENT: pure substance, consisting of only 1
type of atom.
 COMPOUND: substance formed from the
chemical combination of 2 or more elements in
definite proportions.
Examples of Compounds:
H2O - water contains H and O in a definite
proportion (2 to 1) This is the formula for
water.
What is the formula for table salt?
Isotopes
 atoms of the same element with
different numbers of neutrons
Isotopes of Carbon
Carbon-12
Carbon-13
Carbon-14
Radioactive Isotopes
 When a nucleus breaks apart, it gives off
radiation that can be detected and used
for many applications.
Chemical Bonds
 Involve valence (outermost) electrons.
 There are 2 types.
1) Ionic Bonds
 Involves a transfer of electrons.
 Produces ions (charged atoms that have gained or lost
electrons)
 Metal + Nonmetal
2) Covalent Bonds
 Electrons are shared between atoms.
 Smallest unit of this type of compound is called a
molecule.
 Nonmetal + Nonmetal or diatomic molecules have this
type of bond.
Chemical Reactions
 Chemical reaction - process by
which atoms or groups of atoms in
substances are reorganized into
different substances.
 Clues that a chemical reaction has
taken place: 1) heat or light
2) see bubbles
3) something new
Chemical Equations
 Chemical formulas describe the
substances in the reaction and arrows
indicate the process of change.
 Reactants are the starting
substances, on the left side of the
arrow.
 Products are the substances formed
during the reaction, on the right side
of the arrow.
Glucose and oxygen react to form carbon
dioxide and water.
Energy of Reactions
 The activation
energy is the
minimum amount
of energy needed
for reactants to
form products in a
chemical reaction.
What is an enzyme?
 An enzyme is a special type of protein
called a catalyst
 Catalyst: substance that speeds up a
reaction because it lowers the activation
energy
 Cells use enzymes to speed up reactions
 Very specific: usually only catalyzes one
item called the SUBSTRATE
How do enzymes work?
 Enzyme comes in contact with substrate
at certain spot called ACTIVE SITE
 Fits together like a “lock & key”
 Bonding at active site weakens the bonds in the
substrate
 Makes it easier to change substrate
What are enzymes used for?
What regulates them?
 Used for digestion, photosynthesis, &
DNA reproduction
 Regulated by changes in pH,
temperature, other proteins, and
chemicals
Enzyme Lab!
Warm up  Make a Venn Diagram for Ionic and
Covalent Bonds.
 Copy the following: 1) What is this
called? Label the reactant(s) and the
product(s)
H2O2  2H2O + O2
Water is soooo special!
 Most abundant compound in living things.
 Liquid at temperatures found over much of earth.
 Expands when freezes, which causes density less than
liquid water. (unusual for a liquid)
What is polarity???
 Polarity is the uneven
distribution of electrons
between atoms in a covalent
bond.
 In water, the oxygen is
slightly negative because
the electrons are attracted
more to it than Hydrogen.
 The hydrogen atoms in
water have a slight
positive charge because
they are missing the
electrons attracted more
to oxygen.
 Because of polarity, the water molecules attract each
other. This is called cohesion.
 Water is also attracted to molecules of different
substances. This is called adhesion.
 Example of adhesion:
water on the sides of a
graduated cylinder.
 Capillary action is
caused by this.
Warm up 9/15 –
Enzymes p. 159
1. What is the function of an enzyme?
2. What type of organic compounds are
enzymes?
3. What substance takes part in an
enzymatic reaction, but is unchanged
by the reaction?
4. Draw Figure 6.18 and label it. (p. 160)
Mixtures
 Two or more elements or compounds that
are physically mixed together, but not
chemically combined. They can be
separated Physically!
Solutions vs. Suspensions
 Can be made with water…the universal solvent.
 Solution = solvent + solute
 solution = homogeneous mixture
Universal solvent!
 Water can dissolve ionic compounds
and other polar molecules…it is
known as the greatest solvent on
earth!
Suspension
 Water and non-dissolved material
with small particles that are
suspended in the water.
Acids & Bases
 pH scale: indicates the concentration of H+ ions
in a solution.
 Below 7 = acid, the lower the number, the more
acidic.
 Above 7 = Base, the higher the more basic
Buffers
 Weak acid/bases that can react with
strong acids or bases to prevent sharp
sudden changes in pH.
Carbon
Compounds
6
C
carbon
12.011
What is organic
chemistry?
 The study of all
compounds containing
the element CARBON
Natural elements: make up 96%
of the mass of a human:
CARBON, HYDROGEN,
OXYGEN, NITROGEN (CHON)
Trace elements: only needed in
small amounts, called “minerals”:
What is a
macromolecule?
 A giant molecule made
up of 100’s or 1000’s of
smaller units called
MONOMERS
Monomers link together
to form large POLYMERS
 formed by polymerization
The types of
macromolecules:
NUCLEIC ACIDS
CARBOHYDRATES
LIPIDS
PROTEINS
Carbohydrates
 Made of Carbon,
Hydrogen & Oxygen
atoms
 Main source of energy
for living things
 Plants & some animals
use for structural
purposes
 Examples: sugars &
starches
 Simple sugars are monosaccharide.
 Two monosaccharides join together to
form a disaccharide
 Longer carbohydrate molecules are
called polysaccharides (starches).
Figure 2-13 A Starch
Section 2-3
Starch
Glucose
Go to
Section:
Lipids (Fats, Oils &
Waxes)
 Made mostly from carbon & hydrogen
 Used to store energy & waterproof
coverings
 Olive oil, peanut oil
 A triglyceride is a fat if it is solid at room
temperature and an oil if it is liquid at
room temperature.
Nucleic Acids
 Made of hydrogen, oxygen,
nitrogen, carbon, &
phosphorus
 Made of monomers called
nucleotides
 Nucleotides consist of
1) a 5 carbon sugar
2) a phosphate group
3) a nitrogenous base
Store and transmit genetic
information.
Proteins
 Made of nitrogen, carbon,
hydrogen, & oxygen
 Polymers of amino acids
 Some control the rate of
reactions and regulate
cell processes
 Some used to form bones
& muscles
 Others transport
substances into or out of
cells or help fight disease