Notes from the Chemistry of Life PowerPoint
The Chemistry of Life:
The nature of matter
Properties 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
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
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)
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
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
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
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
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:
Enzymes
Catalyst = substance that speeds up a chemical reaction
Lowers activation energy
Enzyme Action
The enzyme-substrate complex
Reactants = substrates
Enzyme has an active site where the substrate binds and is transformed
into products
"Lock and Key" (each enzyme is specific to its substrate)
Regulation of Enzyme Activity
Human body = 37C
Most enzymes work best at a specific temperature and pH (depends on
enzyme)
Enzymes play essential role in:
Regulating chemical pathways
making materials that cells need
releasing energy
transferring information