Chp 2 Chemical Elements and Compounds
Matter
Element
Compound
Life requires 25 of the 92 natural elements
Trace elements
Atom
“Dalton”
Atomic number
Mass number
Isotopes
The chemical behavior of an atom depends mostly on the # of electrons in the outermost shell
Bonds
Covalent bonds
Electronegativity
Nonpolar covalent bond
Polar covalent bond
Ionic Bonds
Positive charge = cation
Negative charge = anion
Weak bonds important in biology.
Hydrogen Bonding
Van der Waals interactions
A molecule’s biological function is related to its shape
Chp 3 Water and the Fitness of the environment
Cells 70-95% water
Water’s Polarity
Cohesion of water molecules
Cohesion
Adhesion
Surface tension
Water moderates temperatures on Earth
Calorie- amount of heat used to raise 1 g of water by 1C
Specific heat- amount of heat that must be absorbed or lost for 1 g of that substance to change
its temp by 1 C
Water = 1 ca/g/C
Evaporative cooling
Heat of vaporization
Evaporative cooling
Ice floats
Water is the solvent of life
Solution- Solvent- SoluteHydrophilic
Hydrophobic
H2O + H2O -> H3O+ (Hydronium ion) and OH- (Hydroxide ion)
H2O <-> H+ and OHAcid-Adds H+ to solution
Base- Soaks up H+ or adds OHpH Scale
Buffers
Buffers accept hydrogen ions when excessive and donating hydrogen ions when depleted.
(usually acid-base pairs)
Carbonic acid (H2CO3)
Chp 4. Carbon and the molecular diversity of life
The importance of carbon
Stanley Miller
The chemical characteristics of carbon are a result of its configuration of electrons
Carbon has little tendency to gain or lose electrons and form ionic bonds
Usually forms covalent bonds by sharing its four electrons
Tetravalence- an intersection point from which a molecule can branch off into four directions
Carbon skeletons: vary in length, double bonds, branching, rings
Isomer
Structural isomers
Geometric isomers
Enantiomers
Functional Groups
Hydroxyl Group: Alcohols –OH
Carbonyl Group: C=O
Aldehyde
Ketone
Carboxyl Group: -COOH
Amino Group: -NH2
Sulfhydryl Group : -SH
Phosphate Group
Chp 5 The Structure and Function of Marcomolecules
Polymer
Monomers
Condensation reaction
Hydrolysis
Carbohydrates
Monosaccharides
Aldose
Ketose
Disaccharide
glycosidic linkage (a covalent bond formed from dehydration reaction)
Polysaccharide
Provide energy storage or used for structural purposes
Starch
Glycogen
Cellulose
Starch- alpha linkage, helical shape
Cellulose- beta linkage, straight shape
Chitin- Similar to cellulose except has a nitrogen containing appendage to the glucose.
Lipids Fats
Fat: fatty acids attached to glycerol
3 fatty acids join to one glycerol
triacylglycerol (or triglyceride)
Saturated fat vs unsaturated fat
Animal fat- usually saturated- solid at room temperature
Plant and fish fat- usually unsaturated- liquid at room temperature
1 gram of fat stores 2x energy as starch
Phospholipids
Micelle
Phospholipid bilayer
Steroid
Cholesterol
Proteins
20 different amino acids
peptide linkage
Function as support, storage, transport, signaling, defense, movement, and catalysts
EnzymesAmino Acid Structure
Amino, carboxyl and R groups
Amino acid linkage
Peptide bond- covalent bond catalyzed by a dehydration reaction
Amino end: N-terminus
Carboxyl end: C-terminus
Four Levels of Protein Organization
Primary- Sequence of amino acids
Secondary- coils or folds
Result from hydrogen bonding on the backbone of the chain (not the R groups)
Alpha helixBeta pleated sheet
Tertiary Structure
Hydrophobic interaction- van der Waals interactions
Disulfide bridgesTwo sulfhyryl groups (-SH) form covalent bond
Quaternary Structure
DenaturationChaperonins- (chaperone proteins)
Nucleic Acids
Purines and Pyrmidines
Deoxyribose
Ribose
Phosphodiester linkagesJames Watson and Francis Crick 1953
Nucleotides
5-C sugar, phosphate and nitrogenous base
Evolutionary relationships