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 + S 8  Al 2 S 8  REACTANTS  PRODUCTS

Parts of a chemical equation  Coefficient  Products  Reactants  Subscript  Yield sign  N 2 + 2H 3  2NH 3

Law of Conservation of Mass  Mass cannot be created or destroyed in a reaction.  Therefore, equations must always be balanced.

Balancing Equations  Al + S 8  Al 2 S 3 ElementNumber of Atoms (reactant) Number of Atoms (products) Al12 S83

Practice Equations  K + B 2 O 3  K 2 O + B  CH 4 + O 2  CO 2 + H 2 O  N 2 + H 2  NH 3

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  Sour taste  Corrosive  RED Bases  Bitter taste  Slippery to the touch  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