BIOL 1201 Chapter : BIOLOGY 1201
BIOLOGY 1201: AUG 28, 2013 8:30 AM
NOTES
• Scientific Method?
1. Observation > Generalization or Model > Predictions or Hypothesis > Test > REPEAT
“Living is our ability to observe phenomenon.”
• What happens as a result of this process?
1. Terminology
o Hypothesis: thought that hasn’t been tested yet
o Theory: has been tested multiple times
o Law: nothing more than a theory, but continues to be tested
• What is Biology?
o What is LIFE?
• Characteristics of Living Systems
Organization
Energy Use
Development
Reproduction: Living things must reproduce to create more living
things
Evolve
Respond to the Environment
To really understand biology, you must understand it from cells to the entire universe.
What determines solubility?
1. Like dissolves like
2. Like in terms of polarity
• Polar solutes dissolve in polar solvents
• Non-polar solutes dissolve in non-polar solvents
What determines polarity?
• Atom
1. Smallest unit of matter separable by normal chemical means
2. The smallest unit of matter that retains all of the properties of that element
Valence
• The number of electrons that need to be gained or lost to fill the outer shell of electrons
• Valence also predicts the number of bonds that an atom will form
• Valence electrons, the electrons in the outermost shell.
Chemical Bonds
• Form when atoms gain or lose or share electrons.
• They are the result of electrical attractions between atoms.
Ionic Bonds
• Form when atoms completely gain and lose electrons.
• Strongest bonds when dry.
Covalent Bonds
• Form when atoms share electrons.
• If shared equally covalent (nonpolar covalent bond).
• If shared unequally polar covalent.
• Strongest bond in water.
Are covalent, polar covalent, and ionic bonds really different bonds?
• Same phenomenon, just being shared differently. Fundamentals of holding bonds
together are really the same.
What determines the number and type of chemical bonds?
• Number of bonds- determined by valence.
• Type of bonds- determined by electronegativity.
Electronegativity
• A measure of the tendency of an atom to attract a bonding pair of electrons.
• Measure of the attraction an atom has for electrons.
Electronegativity and Bonds
• Ionic- when differences are 1.7 or greater, the bond is usually ionic.
• Covalent (nonpolar)- when differences are less than 0.5.
• Polar covalent- anything else in between.
How do bonds influence the polarity of a molecule?
• Molecules which contain the majority of ionic bonds will be polar.
• Molecules which contain the majority of polar covalent bonds will be polar, with a few
exceptions.
• Molecules which contain the majority of covalent bonds will be nonpolar.
Weak bonds
• Bonds which are not involved in making a substance.
Hydrogen Bonds
• Weak attractions between atoms on different molecules or different parts of a large
molecule.
• Occur between molecules that have polar covalent or ionic bonds.
• Always involve hydrogen.
Molecules and Compounds
• Compound
A substance consisting of two or more different atoms, in specific proportions bonded
together in a specific pattern.
• Molecule
Smallest unit of a compound that retains all properties.
Molecular Formulas
• Water H2O
• Carbon Dioxide CO2
• Glucose C6H12O6
Isomers
• Molecules with the same molecular formula, but a different arrangement of atoms.
Molecular Weight
• The sum of the atomic masses for all of the atoms in a molecule.
• Molecular weight of Sucrose: 342
• Molecular weight of Insulin: 5727
Gram Molecular Weight
• The mass of a substance equal to its molecular weight in grams.
• Contains a constant number of molecules.
• Avogadro’s Number of Molecules
1. 6.022 x 10^23
Moles and Molecular Concentrations
• 1 Mole= the mass of a substance equal to its gram molecular weight.
• 1 Molar Solution= a solution containing 1 mole of a substance per 1 liter of solution.
Document Summary
Notes: scientific method, observation > generalization or model > predictions or hypothesis > test > repeat. Reproduction: living things must reproduce to create more living. To really understand biology, you must understand it from cells to the entire universe. What determines solubility: like dissolves like, like in terms of polarity, polar solutes dissolve in polar solvents, non-polar solutes dissolve in non-polar solvents. What determines polarity: atom, smallest unit of matter separable by normal chemical means, the smallest unit of matter that retains all of the properties of that element. Chemical bonds: form when atoms gain or lose or share electrons, they are the result of electrical attractions between atoms. Ionic bonds: form when atoms completely gain and lose electrons, strongest bonds when dry. If shared equally covalent (nonpolar covalent bond): form when atoms share electrons, strongest bond in water. Are covalent, polar covalent, and ionic bonds really different bonds: same phenomenon, just being shared differently.
