Evolution
Unity and diversity of life explained by the theory of evolution
Darwin's "Natural Selection
1. Populations grow faster than food supplies = a struggle to . survive.2. Offspring have variations; favorable traits will be passed on for survival.3. "survival" of the fittest
Artificial Selection
Humans pick and choose what genes will be passed on ex. selective breeding in dogs
Biological Domains
Bacteria, Archaea, and Eukaryotes (BAE)
Prokaryotes
Unicellular, lack membrane bound organelles and a nucleusinclude: Bacteria and Archaea (extremophiles)
Eukaryotes
Include membrane bound organelles, can be unicellular or mulitcellular
Biological Scale
Biosphere, Ecosystem, Community, Population, Organism, Organ System, Organ, Tissue, Molecule, Atom
Reductionism approach
Breaking components down into simpler parts
Systems approach
Holistic objective of understanding how all parts of a system work together to produce emerging properties
Observation/Theory-based science
Theory: explains a great diversity of observations and is supported by a great body of science
Hypothesis-based science
Educated guess; tentative explanation
Scientific Method
ObservationQuestionHypothesis/Prediction Experiment Analyze Make Conclusions
Atomic Mass
Protons + Neutrons (Neutrons can vary which are called isotopes)
Atomic Number
Number of protons*Usually determines what the element is
Ionic Bonding (molecules/compounds)
Charged ions are attracted to each other -Cation ion is the positive ion, donating e--Anion is negatively charged, gains e-
Covalent Bonding
Co-sharing of valence electrons, forming molecules.
Nonpolor Covalent Bonds
equal sharing of electrons e-
Polar Covalent bonds
allows one atom to 'hog' electrons and become slightly negative while other atom is slightly positive
Hydrogen Bonding
Hydrogens connected to oxygen or nitrogen form polar bondsboth very electronegative ex. DNA Base Pairs
Van Der Waals forces
A weak attractive force between atoms or nonpolar molecules caused by a temporary change arising from a brief shift of electrons ex. Lizards 'geko' pads help stick on walls and etc.
Electronegativity
influenced by an elements's density and fullness of a valence shell
Emergent Properties of Water
Based on hydrogen bonding between its polar covalent molecules 1. Cohesion: Adhesion and surface tension -Cohesion (like molecules) because of H bonding-Adhesion (unlike molecules)where water sticks to other substances like a droplet on a leaf-Surface tension extra strong due to cohesion. 2. Temp. moderation-Large bodies of water heat slowly and cool slowly and have a high specific heat capacity-Water phase changes: Large amount of energy to vaporize and large amount of energy to take away to freeze 3. Insulation -bc ice is less dense than water and can insulate objects from colder temperatures4. Water acts as a solvent -Solvent because of its polarity, can form hydration shells around each ion. Hydrophilic - water loving substance (polar or ionic), hydrophobic - water fearing substance(non-polar).
pH Balance
1 to 14 Acidic (1)-Neutral (7)-Basic (14)
Buffers
Resist pH changes ex. carbonic acid and bicarbonate ion maintain pH in body(Left to resist drop in pH) H2CO3 <-> HCO3- + H+( Right to resist rise in pH)
Carbon
-Can bond with up to 4 different atoms-can have single, double, or triple bonds
Isomers
Structural Isomers: same molecular formula but differ in 3-D shapeCis-trans (geometric) Isomers: different in functional groups around a double bond since a double bond does not allow for rotation
Functional Groups
chemically reactive groups of atoms within an organic molecule with specific chemical properties
-OH
Hydroxyl-alcohols
>C=O
Carbonyl-aldehyde and ketone
-COOH
Carboxylic acid
-NH2
Amino Acid
-SH
Sulfhydryl-forms bridges from cysteine amino acids
-PO4
Phosphate-ATP, and methyl
-CH3
methylating DNA to turn genes off (sometimes on)
Biological Molecules (CLPN)
1. Carbohydrates: sugars and starches (monosacrides: glucose and fructose, disaccrides: sucrose and maltose, polysaccrides: starch and cellulose)2. Lipids: fats and oils, steroids, phospholipids 3. Proteins: amino acids4. Nucleic Acids: DNA and RNA
Starch v. Cellulose
starch: stores energy, forms long chains of glucose that do NOT stick togethercellulose: is for strength, forms long chains of glucose that hydrogen bond together****Humans CAN digest starch, but not cellulose (Cows can though)
Dehydration synthesis v. Hydrolysis
monomers to polymers v. polymers to monomersWater removed to link monomers into a polymer; Water added to split polymer into monomers.
Triglycerides
Fats and oils, glycerol plus 3 fatty acids
Proteins
polyemrs of amino acids, 4 levels of structure 1. Primary: determined by DNA code2. Secondary: Beta-sheets or alpha-helix3. Tertiary: Disulfide, ionic bonding: hydrophobic core 4. Quaternary: interaction betwn 2+ proteins
Nucleic Acids
Differences between RNA and DNA