Chapter 2
The Chemistry of Life
The Atom
The Atom on Motion
Terminology
• Element – A pure substance that consist entirely of one
type of atom
– Ex. Gold (Au)
• Isotope – Atoms of the same element that differ in the
number of neutrons they contain
– Ex. Carbon-12 and Carbon-14
• Compound – A substance formed by the chemical
combination of two or more elements
– Ex. Salt (NaCl)
• Molecule – Two or more atoms held together by
covalent bonds
– Ex. Water (H2O)
Atomic Bonding
• Ion – Any atom with a charge due to the loss
or gain of electrons
– Ex. Hyrdoxide (OH-)
• Ionic Bond – a bond characterized by the
TRANSFER of electrons from one atom to
another
• Covalent Bond – a bond characterized by the
SHARING of electrons between two atoms
Dogs Teaching Chemistry
van der Walls Forces
• Slight attraction that develops between
oppositely charged regions of nearby
molecules
Skill Check
• What is the biggest difference between an
electron and a proton or neutron, other than
charge or location?
• Where are protons and neutrons located in an
atom?
• What is another name for the outermost electron
shell?
• What is the difference between an ionic bond
and a covalent bond?
• Why can geckos scale walls like Spider-Man?
Properties of Water
Properties of Water
• Universal Solvent – because water is a polar
molecule (Solution, solute, solvent)
• Cohesion – because of hydrogen bonding (water
molecules like to stick together)
• Adhesion – Water likes to stick to other things
(meniscus)
• Surface Tension – Top layer of molecules is more
attracted to itself than air
• High Heat Capacity – Temperature stabalizer, not
a good conductor
Acids, Bases and pH
• Acid – compound that releases a proton (H+) when it
dissolves in water
• Base – compound that takes up a proton (H+) when it
dissolves in water
• pH – a universal scale measuring the H+ concentration of
solutions
Chapter 2.3
Carbon Compounds
Skills Check
• What is an element?
• What is the difference between a molecule
and a compound?
• What is a covalent bond?
• What is are the outermost electrons called?
• What is the Octet Rule?
Intro to Organic Chemistry
• Organic Chemistry is a branch of science
dedicated solely to the study of the carbon
atom.
• Carbon atoms have 4 valence electrons.
• Carbon can form millions of different
molecules, in a variety of shapes.
Intro to Macromolecules
• Macromolecules are giant molecules made
from hundreds or thousands of smaller
molecules.
• The smaller molecules are referred to as
monomers.
• Monomers join together to make polymers.
• The process by which monomers join to make
polymers is called polymerization.
Macromolecule Groups
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•
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•
Carbohydrates
Lipids
Nucleic Acids
Proteins
Group Time
• Please split up into 4 groups.
• You will be handed a worksheet pertaining to
one of the four groups of macromolecules.
• Using your book, take a few minutes to finish
the worksheet as a group.
• Nominate one or two presenters to come up
to the board and teach the rest of the class
what you have learned about your
macromolecule.
Carbohydrates
Carbohydrates (cont’d)
Lipids
Lipids (cont’d)
Nucleic Acids
Nucleic Acids (cont’d)
Proteins
Protein (cont’d)
Macromolecule Animation
• http://learn.genetics.utah.edu/content/begin/
cells/scale/
Chapter 2.4 & 2.5
Chemical Reactions and Enzymes
Chemical Reactions
• Chemical Reaction – Process that changes one set
of chemicals (the reactants) into another set of
chemicals (the products)
–Ex. 2H + O  H20
• Oxidation reactions are slow, other reactions are
faster (think explosions)
• All chemical reactions involve the breaking and
forming of bonds
How do Chemical Reactions Start?
• Some are spontaneous
– Spontaneous reactions release energy
How do Chemical Reactions Start?
• Some are not
– These reactions require the input of energy to
begin (referred to as Activation Energy)
Where Can We Get Some Activation
Energy?
• From Catalysts, of course!
• Any substance that speeds up a reaction is
called a Catalyst.
• Examples of catalysts:
Enzymes
• Enzymes are proteins that act as catalysts
inside the body.
• Enzymes are specialized to work best at a
certain pH and a certain temperature.
• Every enzyme has an “active site” where
substrates can attach or bind