Second lecture a janusry 27 2011

Bio 101 Dr. Barton [email_address] . Please sign the class list next to your name.

16 weeks two lectures per week one lab per week as listed in syllabus Test every third week at the end of the Friday class . There will be a total of 5 tests. The lowest score will be dropped unless a test is missed .

First week: chapters 1-3 Second week: chapter 4 Third week: chapter 5 Pay attention to the Learning Outcomes highlighted in each chapter. Test questions will be multiple choice or short answer questions modeled on the questions at the end of each chapter.

Question Hypothesis Predictions Experiments Conclusion Scientific Method Proven hypotheses lead to theories.

1858 Hypothesis: Natural selection is the mechanism for evolution. Individuals possessing attributes that give them an advantage in their environment are more likely to survive and reproduce. Therefore the population gradually changes. Decent with modification = evolution

Oxygen oxidizes things, oxygen always gains electrons Oxidized molecule looses electrons. Oxidation is the loss of electrons. Reduction is the gain of electrons. In an oxidation reaction, oxygen itself is reduced.

Each period: same # valence electrons in in outermost shell

Atomic mass is the sum of the mass of electrons, protons and neutrons . Isotopes have same number of protons and electrons but differ in the number neutrons.

Co valent bonds Molecules contain 2 or more atoms joined by covalent bonds. The resulting molecule has no net charge. The octet rule is satisfied, therefore there are no unpaired electrons.

Structural formula Molecular formula

Covalent bonds can be polar or non polar depending on the individual atom’s affinity for electrons ( electronegativity )

Hydrogen bond is a fixed length causing ice to be less dense than liqiud.

Properties of Water mostly liquid at earth surface Can adhere to other polar molecules (capillary action)

One ml (cc) of water at 25 0 C and 1 atmosphere weighs 1 gram (g) One gram of hydrogen contains 6.02 X 10 23 molecules 6.02 X 10 23 molecules = 1 mole

Molecular weight = weight of one mole One mole of hydrogen weighs 1 g One mole of oxygen weighs 16 g Molecular weight of water is 2 X 1 g + 1 X 16 g = 18 g The molecular weight of water is 18 g

1 liter = 1000ml = 1000g Molecular weight of water is 18 g/mole One liter of water contains 1000/18 55 moles of water

Water undergoes ionization: H 2 O OH - + H + At 25 0 C one liter of water contains 10 -7 mole of H + ions.

Acids and Basis pH is a measure of the concentration of hydrogen ions in solution. pH is measure of the [H + ] in solution. pH = -log [H + ] pH scale is 0 to 14 (acidic to basic)

pH = -log [H + ] 0.1 mole H + /liter has a pH = 1 (-log 10 -1 = 1) 10 -14 mole H + /liter has pH = 14 (-log 10 -14 =14) pH scale is 0 to 14 (acidic to basic)

Buffers stabilize pH. At their buffering range they bind excess [H + ] as pH decreases and supply [H + ] as pH increases. Dissolved carbon dioxide (carbonic acid/bicarbonate)is the key buffer in human blood. It’s buffering range is from pH 4 to 6.

Eratosthenes (Er-uh-tos-thuh-neez)

Second lecture a janusry 27 2011

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Second lecture a janusry 27 2011