BIOL 120Final Study GuideCells and Cell theory- Cell Theory: all organisms are made of cells and all cells come from preexisting cells o Discovered by Louis Pasteur - Cell: a highly organized compartment bounded by a plasma membrane Basic atomic Structure- Element: a substance that can’t be broken down into another substance by chemical reactions- Atomic number: number of protons in the nucleus - Atomic mass: the number of protons and neutrons - Isotopes: an atom with the same number of protons, but a different number of neutronso i.e. Carbon has 6 p and 8n  At. Wt. = 14 and Carbon has 6 p and 6 n  At. Wt. = 12- Protons: positively charged particles- Neutrons: neutral particles- Electrons: negatively charged particles - Molecule: a substance made from two or more atoms of similar or different types (form when atoms bond to each other)o Most important to life is water because it forms hydrogen bonds - Energy: the capacity to do work or supply heat and is either stored potential energy or active motion - Chemical energy: potential energy that is stored in chemical bonds (ATP)- Thermodynamics: o 1st law: energy cannot be created or destroyedo 2nd law: spontaneous natural processes increase entropy overall Chemical Bonds- Chemical reaction: when an atom gives up, gains, or shares one or more electrons with another atom- Covalent Bond: each atom’s unpaired valence electrons are shared by both nuclei to fill their orbitalo Non polar- equal electronegativityo Polar- unequal electronegativityo- Ionic bond: results from the attraction of a cation and aniono Ion: an atom or molecule that carries a charge from either losing or gaining an electrono Cation: an atom that loses an electron and becomes positively chargedo Anion: an atom that gains an electron and becomes negatively charged Water- Most important chemical property  can form hydrogen bonds - A great solvent  due to the covalent bonds being polar it can bond to other atoms - Hydrogen bonds: the weak electrical attractions between the partially negative oxygen of one molecule and the partially positive hydrogen of a different water moleculeo Hydrophilic: can dissolve; “water loving” i.e. sugaro Hydrophobic: uncharged and nonpolar compounds that repel from water i.e. oil/fatFunctional Groups- Amino and carboxyl groups: gain or lose protons (NH2 or NH3  amino acids)- Carbonyl groups: site of reactions that link molecules into larger, more complex compounds (COOH)- Hydroxyl groups: acts as weak acids (OH) - Phosphate groups: Have two negative charges (needed for ATP and nucleic acid)- Sulfhydryl groups: atoms linked together through disulfide bonds (the SH in proteins) - Hydrocrabons: molecules consisting only of C and H  nonpolar and other functional groups add chemical properties to it Carbohydrates- monosaccharides: one sugar molecule- Polysaccharides: many sugar molecules - Functions:o raw material for synthesizing other moleculeso provide cell structural support, can indicate cell I.D.o store chemical energy needed for cell functions o Molar ration= C:H:O  1:2:1- Glycosidic linkage: a covalent bond between two hydroxyl groups occurring from a dehydration reaction that causes simple sugars to polymerizeNucleic Acids- Nucleotides: consist of a pentose sugar (5 carbon), phosphate group (bonds to C5) and a nitrogen containing base (bonds to C1)- Nucleic Acid: a polymer of bonded nucleotides that go through a condensation reaction- two types of nitrogenous bases:o Purines (double ring structure): Adenine, Guanineo Pyrimidines (single ring structure): Thymine (only in DNA), Cytosine, Uracil (only in RNA)-- DNAo primary structure: consist of a sequence of nitrogen- containing basis (ATGC)o Secondary structure: consist of 2 DNA strands running in opposite directions o Watson and Crick  DNA strands run in opposite directions of each other Sugar phosphate back bones are hydrophilic and face the exterior of the structure  Nitrogenous base pairs face interior (hydrophobic) Purines always pair with pyrimidines and not with themselves and vice versa- A-T has a two hydrogen bond- C-G has a three hydrogen bond DNA has different size grooves- major and minor  DNA can store and transmit biological informationo Strands grow in 5’ to 3’ directiono Chargaff’s rule  equal proportions of Purines (A and G) and Pyrimidines (C and T)- amount of adenine = amount of thymine- amount of cytosine = amount of guanine o DNA is a double helix  A forms 2 hydrogen bonds with T C forms 3 hydrogen bonds with GDNA Replication - Occurs in interphase- DNA copies are semiconservative (part of the old strand bonded with new strand)- Requireso Paternal DNA to copy (and primer)o Enzymes to copy DNAo NTPs (building blocks to make copy of DNA)- Processo Initiationo Elongationo Termination - Process is Semi- discontinuous o Leading strand (5’ 3’) synthesized continuously o Lagging Strand (3’  5’) synthesized discontinuously with multiple priming events  copies in short fragments  Okazaki Fragments - main replication polymerase  DNA polymerase epsilon and DNA polymerase delta- RNAo Same as DNA except: Contains Uracil instead of Thymine  Single stranded Contains ribose instead of deoxyribose - RNA molecules act as links between genes - Messenger RNA (mRNA)  carries information from DNA to site of protein synthesiso Enzyme RNA polymerase synthesizes RNA according to the information given through the sequence of bases in a gene o After RNA synthesis it is processed in the nucleus and then used for protein synthesis in cytoplasm - tRNA  bring amino acids to the site of polypeptide synthesis based on codon on mRNAo codon genetic code which is a group of 3 bases on mRNA that tRNA recognizes o mRNA and t RNA pair up- rRNA  synthesizes ribosomes Lipids- Lipids: loosely defined group of molecules with one main chemical characteristic  insoluble in water examples: fats, oils, waxes, steroids. Etc.- Made from:o Fatty Acids  long chain hydrocarbons with COOH at one end Saturated: no double bond between carbon atoms (high melting point, animal origin i.e. butter Unsaturated: 1 or more double bonds (low melting point, plant origin i.e. olive oil) Monounsaturated: fatty acid with one double bond  Polyunsaturated: fatty acid with more than one double bond Trans fat: fats produced industrially - Phospholipids: consist of 2 fatty acids joined to a polar