Science Warm-up 1/9/2012
 You are a home builder. You just receive
word that you are supposed to build a brand
new house for someone. What process, or
order, would you go through to build the
house. Ex) The first thing I would do is draw
out my blueprints. This should be 5 sentences
and left in your folders.
Chapter 6: Chemistry in Biology
Wood
Biology B
Fall 2011
BIG Idea (p.146)
 Atoms are the foundation of biological
chemistry and the building blocks of all living
organisms.
Section 1: Atoms,
Elements and
Compounds
Concepts for Section 1
 Atoms
 Elements
 Isotopes
 Compounds
 Van der Waals forces
 Ionic vs. Covalent Bonds
Atoms (p.148)
 Atoms are composed of protons, electrons and
neutrons.
 Charges of those particles:
 Proton +
 Neutron X
 Electron -
Elements (p.149)
 An element is a pure substance that cannot be
broken into other substances.
Isotopes (p.150)
 Isotopes- Atoms of the same element that
have different amount of neutrons.
Compounds (p.151)
 Compounds are formed when two or more
different elements combine.
Ionic vs. Covalent Bonds (p.152)
 Covalent bonds form when electrons are
shared.
 Ionic Bonds form when there is an electrical
attraction between two ions.
 Ions are charged particles.
Van der Waals Forces (p.155)
 Attractive forces between positive and
negative regions of molecules.
Chapter 6, Section 2
Chemical Reactions
Concepts of Section 2
 Chemical Reactions
 Balancing Equations
 Endothermic vs. Exothermic Reactions
 Enzymes
What are chemical reactions?
(p.156)
 Chemical reactions- are where atoms or
groups of atoms are reorganized into different
substances.
 Are these important? Why or why not?
Chemical vs. Physical Changes
 Changes can either be chemical or physical
changes. How can we tell the difference?
 Chemical changes usually produce light, form
a new gas/solid, or the releasing of heat.
Chemical equations (p.157)
 There are two parts for every chemical
reaction. There are the reactants and the
products.
 2Al + S8  Al2S8
 REACTANTS  PRODUCTS
Parts of a chemical equation
 Coefficient
 Products
 Reactants
 Subscript
 Yield sign
 N2 + 2H3  2NH3
Law of Conservation of Mass
 Mass cannot be created or destroyed in a
reaction.
 Therefore, equations must always be
balanced.
Balancing Equations
 Al + S8  Al2S3
Element
Number of Atoms
(reactant)
Number of Atoms
(products)
Al
1
2
S
8
3
Practice Equations
 K + B2O3  K2O + B
 CH4 + O2  CO2 + H2O
 N2 + H2  NH3
Endothermic vs. Exothermic
(p.158)
 ENDO-thermic
 EXO-thermic
 ENDO- energy is absorbed and goes IN
 EXO- energy is released and goes OUT
Reaction graphs
Enzymes (p.159)
 A catalyst is a substance that lowers the
activation energy of a reaction.
Enzymes cont.
 Enzymes are the biological catalysts.
 Without enzymes human life would not be
possible.
 These are like the frying pans of chemical
reactions.
Section 3: Water and
Solutions
Section 3 Concepts
 Polarity
 Mixtures
 Acids and Bases
 pH
Polarity (p.161)
 Molecules that have an unequal distribution
of charges are polar molecules.
 For water, this is created through the
formation of hydrogen bonds. (what connects
the hydrogen to the oxygen)
Mixtures (p.163)
 Homogeneous mixtures
 Uniform throughout
 Heterogeneous mixtures
 You can pick out the individual pieces.
Homogeneous Mixtures
 Solute
 The substance that is dissolved
 Solvent
 The substance something is being dissolved
in.
Acids and Bases
 An acid falls on the scale between 0 and 7
 A base falls onto the scale between 7 and 14
 A neutral falls onto the scale at 7
Acids vs. Bases
Acids
Bases
 Sour taste
 Bitter taste
 Corrosive
 Slippery to the touch
 RED
 Commonly used as
cleaners
 BLUE
Section 4
The Building Blocks of Life
Concepts for Section 4
 Carbon
 Macromolecules (4)
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids
Carbon
 Carbon is the basis of organic chemistry.
 If a molecule does not contain carbon, the
molecule is more than likely not living.
Macromolecules
 Macromolecules are large molecules that are
formed of smaller organic molecules, or
building blocks.
Carbohydrates
 Carbohydrates are chains of sugars
(saccharides)
 One sugar = mono-saccharide
 Two = di-saccharide
 These are commonly found in bread
pasta and other “starchy” foods.
Carbohydrates
 Store energy
 Provides structural support
 Building block: saccharides
Benedict’s Test
 What am I testing for?
 Sugars (aka saccharides)
 What is a positive test?
 Solution turns red, green or yellow.
Iodine Test
 What am I testing for?
 Starches (complex sugars)
 What does a positive test look like?
 The solution turns purple
Lipids
 Stores energy
 Provides steroids
 Waterproofs coatings
 Ex) vegetable oil
 Building blocks: fatty acids
Brown Paper Test
 What am I testing for?
 Lipids
 What does a positive test look like?
 The paper becomes opaque and oily
Protiens
 Transports substances
 Speeds reactions
 Provides structural support
 Provides hormones
 Ex) Steak
 Building Block: amino acids
Biuret’s Test
 What am I testing for?
 Peptide bonds in proteins
 What does a positive test look like?
 The solution turns purple
Nucleic Acids
 Stores and communicates genetic material.
 Ex) DNA
 Building block: nucleotides