chemical basis of life. chemistry matter is made up of separate chemical components. –chemistry =...
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Chemical Basis of Life
Chemistry
• Matter is made up of separate chemical components.– Chemistry = Interactions between atoms/molecules.
• Biological function begins at the chemical level.– Hierarchical interactions add function.– Ex. Photosynthesis
Sub-cellular concepts
• Matter
• Elements
• Atoms
• Natural elements– 92– About 25 essential for life– H,O,N,C = 96% of human body– Trace elements
Periodic Table of Elements
Atomic Structure• 3 Basic subatomic particles.
– Proton– Electron– Neutrons
• Atomic Number
• Atomic Mass
• Compounds
Isotopes• Atoms representing different forms of the
same element.
• Same number of Protons, but different mass– Different number of neutrons
• Radioactive Isotopes
Electrons
• Arranged in shells
• Valence
• Reactivity
• Molecules
Molecular Structure• Structural formula
• Ball and stick
Chemical Bonding – Ionic Bonds
• Form between Ions of opposite charge
• NaCl– One atom gives up e- (cation).– One atom recieves e- (anion).– Results in filled outer shells for both.
Chemical Bonding – Ionic Bonds
Chemical Bonding – Covalent Bonds• Result from electron sharing.
– 1 or more pairs of outer shell electrons.– Number of possible bonds = number
needed to fill outer shell.
Chemical Bonding – Hydrogen Bonds
• Attraction between the (+) and (-) ends of a water molecule
• Weak bonds
• Hydrogen = positive end
• Oxygen = negative end
Water
• Polar molecule– Electronegativity– Polar covalent bonds
• Cohesion
• Adhesion
• Resistant to temperature change
More Definitions
• Solutions– Solvent– Solute
• Aqueous solution = Water is the solvent– Water = Universal solvent– Results from the Polarity
pH
• Potential hydrogen.
• H2O dissociates into H+ and OH- (hydroxide) ions.– Acids– Bases
• pH scale
pH Scale
Chemical Reactions
• Processes producing chemical changes in matter.– Reactants– Products
• Matter cannot be created or destroyed
• Energy flow
Types of Chemical Reactions
• Synthesis – Ex. A + B => AB
• Decomposition– Ex. AB => A + B
• Exchange– Ex. AB + CD => AC + BD
• Oxidation-Reduction (redox)– Ex. C6H12O6 + 6O2 6CO2 + 6 H2O + ATP