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Chapter 2: The Molecules of Life (ATOMS (Protons #, Electrons #, Neutrons,…
Chapter 2: The Molecules of Life
ATOMS
Protons
#
Electrons
#
Neutrons
Atomic Mass: Protons+Neutrons
Isotopes
Cations: More protons than electrons
Anions: More electrons than protons
Molecules and Chemical Bonds
Covalent Bonds: Shared Electrons
Polar Covalent Bond: Electron unequally shared
Nonpolar Covalent Bond: electron equally shared
Double Bond
Ionic Bond: Electron is "Transferred" between atoms
Electronegativity
Atoms in upper right of periodic table have highest electronegativity
At physiological pH functional groups ionize
Amine (NH2) gains H
Carboxyl (COOH) loses H
Aldehyde (C double bond O H) no change
Carbonyl: c double bond O
Water
Hydrogen Bonding
Contributes to water's properties
Solid State less dense than liquid
High Specific Heat
Cohesion
When hydrogen bonds with F, O, or N (Electronegativity)
Hydrophilic & Hydrophobic Molecules
Hydrophobic Effect: Polar molecules exclude nonpolar ones
Carbon: Life's Chemical Backbone
Organic Molecules contain carbon
Carbon forms four Covalent Bonds
Tetrahedral Chemical Structure (Methane)
Isomers: Molecules with same chemical formula, different structures
Carbon can come together in rings, lines, or chains.
Organic Molecules
Nucleic Acids
Polymers of NUCLEOTIDES
Nitrogenous Bases
Cytosine, Thymine, Uracil are Pyrimidines (1 Ring)
Guanine and Adenine are Purines (2 Rings)
Phosphodiester Bonds (Phosphate to Sugar)
Encode and Transmit Genetic Information
Deoxyribonucleotide
Ribonucleotide
Carbohydrates
Polymers of SACCHARIDES
Complex Carbohydrates are long branched chains of sugars
Energy Source, make up cell wall
Glycosidic Bonds
Contain C, H, O in 1:2:1 ratio
Saccharides
Galactose (Aldose)
Glucose (Aldose)
Fructose (Ketose)
Glucose + Fructose = Sucrose
Galactose + Glucose = Lactose
Proteins
Polymers of AMINO ACIDS
PEPTIDE BONDS join Carbon in Carboxyl and Nitrogen in Amino
Provide Structural support and act as catalysts
Lipids
Consist of FATTY ACIDS
Triacylglycerol
Glycerol
Saturated fatty acids do not contain double bonds
Unsaturated fatty acids contain C-C double bonds
Make up Cell Membranes
Steroids
Cholesterol has core with 20 carbon atoms in four rings; hydrophobic
Precursor for steroid hormones
Phospholipids: Major component of cell membrane
Fatty acids are linear hydrocarbon chains; carboxyl group at one end.
