species
a group of physically similar organisms
Carl Linneaus
created the hierarchal system of taxonomy (putting species into groups) in the
... [Show More] 1700s. He was organizing God's creations (no evolution implied)
AD
Spontaneous Generation
believed until 1668. Life arose from nonliving organisms. Disproved by Redi.
Redi's experiment
2 jars: one covered with rotting meat in it and another one uncovered with rotting meat. the uncovered one got maggots and the covered one did not; disproved spontaneous generation.
Robert Hooke
Discovered cells in cork in 1655 using his own microscope.
van Leeuwenhoek
(1600s) found single celled organism and called them animalcules. made best lenses for one-lens microscope.
The Cell Theory
all living organisms are made of cells and the products of cells and all cells are produced by cells.
Louis Pasteur
(1860s) used an experiment to see if organisms need air to survive. found evidence to support this: if you boil broth, you kill all the cells in it. if you wait a while, cells return (from being in the air and landing in the broth) and the broth stinks/rots. Next experiment:sterile broth in swan neck flask. Condensation collects in the U - It traps microorganisms.
Breaking off the neck allows microorganisms access to broth - not trapped.
Theory of Evolution
1. there are variations of traits within populations of individuals that make up a species. 2. these traits are heritable. 3. certain traits allow for better survival of individuals (natural selection)
Covalent bonds
formed by sharing electrons between two atoms.
electronegativity
how much an atom attracts electrons
polar covalent bond
unequal sharing, causes partial charges (H2O)
Oxygen and Nitrogen
they really like electrons about the same amount
Hydrogen and Carbon
They only like electrons a little bit about the same amount
Ionic Bonds
formed by one atom taking electrons from another atom
Hydrogen Bonds
1/20th the strength of a covalent bond. Weak.
Water Ionization
low pH = [H+] (acidic)
High pH = [OH-] (basic)
Hydrophilic
attracted to water
Hydrophobic
afraid of water
Carbon
can make any kind of structure by using it as a backbone, uses covalent binds to fill outer valence shell, can make 4 covalent bonds (more than any other molecule)
Representations of organic molecules
Graphs, space filling model, hexagons = carbon rings, lines = covalent bonds
Carbon-Containing Organic Molecules
structure and movement are important, reacts to make other molecules
Hydrophobic Interactions/Bonds
do not bind with each other, but refuses to bind with water. hydrophobic associates with hydrophobic. Water would rather have one big bubble than small ones (oil in water, reduces surface area and minimizes interactions)
Chemical bonds
strong = covalent, weak = H bonds, van der Waals, hydrophobic "bonds" (interactions)
What makes a spontaneous reaction?
depends on temp, release of energy from bonds, changes in entropy = changes in Gibbs free energy (ΔG)
ΔG (Gibbs Free Energy)
Negative = exergonic, positive = endergonic
Energy of Activation (Ea)
Catalysts help reactions by lowering the energy of activation (Ea). the minimum energy that must be input to a chemical system with potential reactants to cause a chemical reaction.
Enzymes
Biological catalysts. usually named "xxx-ase." Can act outside living cells (Buchner 1907 Nobel Prize). Pasteur called them "ferments." When adding a catalyst to an equilibrium-level reaction, there is no change.
Reduced Carbon
has more energy than oxidized because it has higher electrons in bonds. Reduces charge. More reduced carbons have more useful potential energy in electrons (CH bonds have more [Show Less]