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Module A Unit 2 Chemical Basis for Life The Chemistry of Life - Elements and Atoms Subatomic Abbr. Particle proton p+ Charge Mass positive 1amu neutron n0 neutral electron e- negative 0amu 1amu Ions: Atom with too few electrons, positive charge cation, or too many electrons, negative charge, anion - Elements and Atoms Why unstable? Outer orbital, valence electrons, are not full - Atoms, Bonding, and the Periodic Table What is C’s atomic number? How many electrons are needed in the outer orbital to be stable? 8 - Ionic Bonds - Covalent Bonds - Covalent Bonds - Covalent Bond Types - Covalent Bonds and Polarity Why are the electrons pulled? The larger nucleus of oxygen pulls hydrogens’ electrons toward it. Properties of Water due to its polarity Cohesion Adhesion Nearly Universal Solvent Why do oil and water not mix? High Specific Heat (thermal capacity) NaCl = ? Na+ + Cl- Disassociation/Dissolving = Ion formation The picture shows a droplet of water hanging on the tip of a leaf. How do the physical properties of water result in the image shown? Cohesion: water forms a droplet Adhesion: water “sticks” to the leaf Van der Walls Forces: force of attraction due to charge Example: DNA double helix Hydrogen Bond Interactions Solid (frozen) water Increase Volume, Decrease Density Liquid water solution Why is it important solid water floats in biology? Ice insulates liquid water below allowing for life to occur. When lettuce is frozen and then thawed, it’s texture changes. Using the image above, why does freezing cause this change? Central vacuole bursts when frozen, causing the leaf cells when thawed to lose turgor pressure and become limp. - Acids and Bases in Solution pH: inverse log scale of hydrogen ion concentration. 1 change in unit on a pH scale is a ten fold change in H+ so 5 to 6 is a decrease 10X in H+ , 5 to 7 a 100X in H+ Affects enzyme activity and therefore cellular chemical reactions Neutralization Reaction NaOH solution = Litmus paper HCl(sol) + NaOH(sol) HCl solution = - Properties of Carbon Organic Molecules: always have ___C___ and ___H___ always form ___covalent______ bonds - Carbon Compounds – Bond types - Life With Carbon Monomers - Life With Carbon Hydrolysis (digestion) vs. Dehydration synthesis Polymer monomers Monomers to Polymer Polymers: long chain compound made of repeating units Monomers: subunits of a polymer Autotrophs Only organisms that have the ability to make their own monomers vs. Heterotrophs Get polymers to digest monomers either directly or indirectly from autotrophs, “eaters” - Life With Carbon Uses: Cell and organelle membranes Energy storage as fats in animals Waxes and oils in plants and animals - Life With Carbon Hydrophilic – water loving head end Hydrophilic – water hating end What are the uses of fats in a single cell compared to a whale? single cell – energy storage whale, blubber for warmth - Life With Carbon Characteristics: Why do insects and plants have waxy coatings? Is wax a saturated or unsaturated fat? Characteristics: Lipids as Chemical Messengers = Hormones - Life With Carbon Example of a carbohydrate Uses: starch plant energy storage and cellulose plant cell walls glycogen – animal energy storage, mostly in liver and muscles MONOSoluble Glucose Primary energy source in cells Fructose Fruit sugar Galactose Component of lactose Sucrose DISoluble Common table sugar; transported in the phloem of green plants (glucose + fructose) Saccharides Maltose Least common natural disaccharide, but an important polysaccharide intermediate (glucose + glucose) Lactose Milk sugar (glucose +galactose) Glycogen Animal energy store in the liver POLYStarch Insoluble: giant glucose polymers Plant energy store; mostly contained in granules in chloroplasts Cellulose Main component of plant cell walls - Life With Carbon - Life With Carbon Use: Codes for amino acid sequence for protein synthesis DNA: Double helix nucleotide base pairing: Adenine - Thymine Cytosine – Guanine Hydrogen bonding holds the two complimentary strands together RNA: Adenine - Uracil Cytosine – Guanine Types: mRNA carries genetic code into cytoplasm tRNA carries amino acids to mRNA for protein synthesis - Life With Carbon G – Guanine C – Cytosine T- Thymine A - Adenine Base Pairing – Van der Walls Forces - Life With Carbon Gene – group of codons instructing the formation of a functional protein - Life With Carbon Peptide Bonds C-N Holds amino acids together to form proteins. Ribosomes use energy as ATP - Life With Carbon mRNA code after DNA to mRNA transcription 3 bases of mRNA codes for 1 specific amino acid - Life With Carbon Amino Acids (AA’s) Known: over 60 In Cells: around 20 in living things, another reason for the idea of evolution common descent - all life is descended from one prokaryotic cell Formed in the Golgi Due to polar and non-polar amino acids - Life With Carbon Uses: Cell structure : Transport proteins Glycoproteins for cell recognition Adhesive proteins to hold cells together in multicellular organisms Enzymes for chemical reactions – affected by temperature, pH and pressure Shape Dictates Function!!!!!! Activation Energy: energy required to start a chemical reaction. It is lowered by the enzyme allowing the reaction to occur or speed it up Reactants: left side of a chemical reaction Products: right side of a chemical reaction Enzymes provide the surface area to reduce the activation energy and allow the reaction to occur Ex: C6H12O6 + 6 O2 6 CO2 + 6 H2O Enzymes – organic catalysts = a type of protein - reduce or eliminate activation energy - unchanged by the reaction can be used over and over Letter at the beach example Lock and Key Theory 1 Enzyme for 1 Reaction: Hydrolysis or Dehydration Affected by temperature, pH and pressure Synthesis -denature: changes shape or completely breaks down into amino acids - example: fried egg, proteins in egg change color from clear to white Protein Synthesis Melanin biosynthetic pathway Multiple enzymes allow for the chemical reactions of melanin production to occur. If one enzyme does not function the reaction stops and thus albinism The only way an enzyme changes shape or mutation is by a DNA Gene Protein Trait The DNA Song Crash Course Biology: Carbon Water Biological Molecules Codes for amino acid sequence for Study Island protein synthesis Organic Molecules and Water 3a and Enzymes 3b