August 23, 2017
What is science?
Process (scientific method)
Study of the natural world
What do scientist do?
Make sense out of the observations that results in creating a model
Assume that the future is like the past
Generalization or Model
Predictions or Hypothesis
What happens as a result of this process?
Models get more accurate
Can get very close to the truth
If you want to learn more check out How the brain influences behavior?
Science starts with observation
Ex: Do animals have souls?
Believed souls had mass
Weighed animals, killed them, weighed again
Technology changes our way we can make observations
Hypothesis: explanation for something thats relatively untested We also discuss several other topics like What are the four levels of management?
Theory: hypothesis tested repeatedly and always supported; model we think is really good Law: shouldn’t have exceptions;
What is biology?
Study of life;
What is life?
Not defined by single characteristic
Characteristics of Life
Organization (Made up of many chemicals but the way our chemicals are organized make us unique)*
Develop and change over your life time
Reproduction: all cells come from preexisting cells*
Evolve: generation of species have to adapt to survive
Respond to environment*
Viruses don’t use energy but are extremely close to life Don't forget about the age old question of What is the freedmen’s bureau?
Scale of Nature & Approaches to Biology
What determines solubility?
Like dissolves like; like in terms of polarity If you want to learn more check out What is the history of evolution in education?
Non polar solutes dissolve in non polar solvents
Polar solutes dissolve in polar solvents
What determines polarity of a molecule?
Bonds in a molecule
Bonds are the result of electrical attractions between atoms
smallest unit of matter separable by normal chemical means and retains all the properties of that element
Structure of atoms tell us how different atoms come together
Protons and neutrons are located in the nucleus of an atom, with electrons orbiting the nucleus. Electron charge: 1
Neutrons: mass of 1 daltons
Electrons: mass of 0 daltons
Atomic number: number of protons
Atomic mass: number of protons and neutrons
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 the atoms will form
Valence electrons, the electrons in the outermost shell
K shell full with 2 electrons; L shell full with 8 electrons; M shell full with 8 electrons Always fill shell from the inside to the outside
Carbon can do a lot of things because it is so flexible with a valence of 4 If you want to learn more check out What are the 5 characteristics that an organism must possess to be considered alive?
Form when atoms completely gain and lose electrons
Strongest bonds when dry
Ex: Sodium 1 valence electron (valence of 7) ; Chlorine 7 valence electrons (valence of 1)
Form when atoms share electrons
If shared equally covalent
If shared unequally polar covalent
Strongest bond in water
Are Covalent, Polar Covalent, and Ionic Bonds really different? deranged sharing of electrons Don't forget about the age old question of Who created the periodic table of elements?
variations of how the electrons are being shared
they are different places along a continuum of sharing
result of electrical attractions
What determines the number and type of chemical bonds? Valence determines the number of bonds
Electronegativity determines the type of bonds
Measure of the tendency of an atom to attract a bonding pair of electrons Measure of the attraction an atom has for electrons
Increases from left to right and bottom to top
Week One PreLecture Notes
Atomic Scale 10^8 meters
Community/Ecosystem Scale 10^6 meters
Keep in mind where we are in that scale
Approaches to biology include reductionist approach (minimalistic) and wholist approach Reductionist approach for 1201
Organisms are composed largely of 11 basic elements. Value in an average human being is about $1,000 dollars. The thing that makes us unique is the organization of these chemicals.
Basic Chemistry Atoms
Smallest unit of matter separable by normal chemical means
Smallest unit of matter that retains all of the properties of that element
Protons: Mass 1 dalton ; Charge +1 ; Location nucleusVal
Neutrons: Mass 1 dalton ; Charge 0 ; Location nucleus
Electrons: Mass ~0 dalton ; Charge 1 ; Location outer shells
Atomic Number: number of protons (and electrons) in an atom
Atomic Mass: number of protons and neutrons in an atom
Isotopes: variants of an atom, having different atomic mass but same atomic number K shell: 2 electrons ; L shell 8 electrons ; M shell 8 electrons
Valence: number of electrons and atom needs to gain or lose to fill the outer shell Valence electrons: amount of electrons on the outside shell
Valence predicts the amount of bonds an atom will form
Figure 2.4 in textbook
Basic Chemistry Bonds
Chemical bonds form when atoms gain and lose or share electrons
Chemical bonds are results of electrical attractions between atoms
Ionic Bonds: forms when atoms completely gain and lose electrons ; strongest when dry Covalent Bonds: forms when atoms share electrons ; can be shared equally (nonpolar covalent bond) or shared unequally (polar covalent) ; strongest in water
Covalent, Polar Covalent and Ionic bonds aren't really that different ; No, just different variations in how electrons are being shared ; on different places along a continuum