The Chemistry of Life:

The nature of matterProperties of water

Atoms

Basic unit of matter Greek (atomos) unable to be cut Subatomic particles protons,

neutrons, electrons Nucleus protons and neutrons

Elements and Isotopes

Elements a pure substance that consists entirely of one type

of atom Number of protons= element’s atomic#

Isotopes Same element different number of neutrons

(same chemical properties) Atomic mass # = weighted average mass of the

isotopes Radioactive Isotopes

Nuclei are unstable and break down at a constant rate

Can be used as a dating tool, treatment for cancer, food sanitation, tracers to follow movement in bodies.

Chemical compounds and bonds

Compound – Formed by the chemical combination of 2 or more

elements in definite proportions Example: C6H12O6 (glucose)

Chemical bonds: Ionic bonds

Electrons are transferred from one atom to another Covalent bonds (strongest bond)

Electrons are shared between atoms Forms molecules

Van der Waals Forces Intermolecular forces – an attraction between

oppositely charged regions of nearby molecules

Computer Modeling:

Intermolecular forces Use the handout from this activity as

notes.

The water molecule

Polarity Uneven distribution of electrons between the H

and O atoms Hydrogen end slightly positive Oxygen end slightly negative

Hydrogen bonds Negative to positive attractions btw molecules Strongest bond that can form btw molecules Cohesion = attraction between molecules of

the same substance (ex. Water on a penny) Adhesion = attraction between molecules of

different substances (ex. meniscus)

Solutions and Suspensions

Mixture = 2 or more elements or compounds physically mixed (not chemically)

2 types = solutions and suspensions Solutions

Components are evenly distributed Solvent (dissolves the solute) ex. water Solute (substance that is dissolved) ex. salt

Suspensions Mixtures of water and nondissolved material Movement keeps material suspended

Blood solution and suspension! Made of mostly water with many dissolved components

(solution) Also contains nondissolved material like blood cells

(suspension)

Acids, Bases, and pH

Acids, Bases, and pH

pH scale = factor of 10 btw steps Acids (strong acid = 0/weak acid = 6)

Forms H+ ions in solution The higher the concentration of H+ more acidic

Bases (strong base = 14/weak base = 8) Forms OH- ions in solution and low concentrations of

H+ The lower the concentration of H+ more basic

Buffers Weak acids or bases that can react with strong acids

and bases to prevent sharp changes in pH Helps to maintain homeostasis in the body (pH of

the body = 6.5 – 7.5)

Computer Modeling:

Properties of Water and hydrogen bonding: Use the handout from this activity as

notes.

Chemistry of Life

Carbon compounds Chemical Reactions and Enzymes

The chemistry of carbon

Organic chemistry: The study of all compounds that contain carbon Can form single, double, or triple covalent

bonds with other carbon molecules Macromolecules:

Monomers – small organic compound units Polymers – many monomers strung together 4 groups = carbohydrates, lipids, nucleic acids,

and proteins

Carbohydrates

Main energy source for living things Can also be used for structural

purposes (ex. cell wall in plants) Made up of C, H, and O ratio of

1:2:1 Monomer = glucose (sugar

molecule) or monosaccharides Polymer = starch or polysaccharides

Computer Modeling:

Carbohydrates: Use the handout from this activity as

notes.

CarbohydrateConstructed Response (formative assessment)

How do intermolecular attractions play a role in the behavior of polysaccharides? Be sure to include how starch and cellulose compare in your response.

Lipids (fats)

Generally not soluble in water Used to store energy, found in

membranes, waterproof coverings, and used as chemical messengers

Typically = glycerol molecule combined with fatty acid molecules

Saturated – maximum # of hydrogen bonds (no double bonds) in a fatty acid

Unsaturated – at least one carbon-carbon double bond in a fatty acid

Computer Modeling:

Lipids: Use the handout from this activity as

notes.

Caption:

Write captions that explain what is happening to the phospholipids in the two pictures.

In Water: In Oil:

Caption:

Bellwork (for the next day):

True or False: Water and Oil repel each other. Why do you think that?

Protein

Contain N, C, H, O Some proteins control the rate of

reactions (enzymes), regulate cell processes, form bone and muscle, cell transport, and fight disease

Monomer = amino acids Polymer = polypeptide or protein

Computer Modeling:

Proteins: Use the handout from this activity as

notes.

Nucleic Acids

Contains H, O, N, C, and P Stores, transmits hereditary/genetic

information 2 kinds = RNA and DNA Monomer = nucleotide (a 5C sugar,

phosphate group, and a nitrogenous base)

Polymer = polynucleotide or nucleic acid

Chemical Reactions

A process that changes one set of chemicals into another Always involves the breaking and formation of

bonds Reactants

Enter into a reaction Bonds are broken

Products Result from a reaction New bonds are formed

Energy in Reactions

Energy changes Release energy spontaneous Absorb energy needs energy to

proceed Where does this energy come from in

plants? Animals?

Activation energy Energy needed to get a reaction started

Activation energy:

Energy-Absorbing Reaction Energy-Releasing Reaction

productsReactants

Activation energy

Activation energyproducts

Reactants

Enzymes

Catalyst = substance that speeds up a chemical reaction

Lowers activation energy Type of Protein

The graphs to the left show the same reaction: X + Y XY, where X reacts with Y, producing XY.

A student gives the opinion that Graph A requires less energy to start the reaction. Is this student right or wrong in their interpretation of the graphs? Interpret what the graphs show (including whether the reaction is energy releasing or energy absorbing) and why the student was right or wrong.