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ATOMS AND ELEMENTS: BUILDING BLOCKS OF ALL MATTER matter mass elements atom: basic chemical unit of matter Structure of Atoms nucleus electron cloud protons (p+) neutrons (n0) electrons (e-) (Dr. O’s philosophical view of the force of life) atomic number atomic mass isotopes radioisotopes radioisotopes (add neutrons) tracers for marking compounds to follow pathway dating old fossil remains used for destructive purposes generate energy Energy-Level Shells energy-level shells (clouds of electrons) COMPOUNDS AND MOLECULES: AGGREGATES OF ATOMS compound molecules chemical bonds Covalent Bonds: Sharing Electron Pairs covalent bond single, double, triple bond nonpolar, polar covalent bond Ionic Bonds: Opposites Attract ion positively, negatively charged cation, anion ionic bonds Hydrogen Bonds Water H2O - dipole molecule + & - charges ACIDS, BASES, AND BUFFERS electrolyte acid, base + pH: Measuring Acidity (H conc) & Alkalinity (OH conc) pH scale acidic, basic solutions pH: Control with Buffers buffers THE MOLECULES OF ANIMALS organic, inorganic molecules single, double covalent bond hydrocarbons functional (active, reactive) groups Carbohydrate: Sources of Stored Energy carbohydrates monosaccharides, sugars isomers disaccharide polysaccharides chitin Lipids: Energy, Interfaces, and Signals lipids, fats fatty acids, glycerol triglyceride saturated, unsaturated, polyunsaturated fatty acid oil, phospholipid, cholesterol, steroidal hormones, vitamin D Proteins: The Basis of Life's Diversity amino acids, proteins, amino group/carboxyl group peptide bonds di-, tri-, polypeptide primary, secondary, tertiary, quaternary structure Nucleotides and Nucleic Acids: Information Storage, Chemical Messengers, & Energy Transfer Nucleotide phosphate ribose sugar nitrogenous base adenosine phosphates ATP/ADP/AMP nucleotide coenzymes nucleic acids deoxyribonucleic acid (DNA) double strand twisted ribose sugar C2 –H nitrogenous bases: adenine/guanine/cytosine/thymine pyrimidine: 1 ring structure cytosine/thymine purine: 2 ring structure: adenine/guanine Chargaff’s Rule (1949) adenine-thymine pairing guanine-cytosine pairing Franklin & Wilkins (1951-53): X-ray diffraction Watson & Crick (1953): Model of the DNA Watson, Crick & Wilkins: Nobel Prize in Medicine or Physiology 1962 function: genetic code (blueprint of life) ribonucleic acid (RNA) single strand ribose sugar C2 –OH nitrogenous bases: adenine/guanine/cytosine/uracil mRNA/tRNA/rRNA function: protein synthesis Miller & Urey 1952 Chemical Evolution heat & sparking inorganic gases, organic methane & waterà organic compounds = building blocks for cellular structures INTRODUCTION hierarchy of biological organization WHAT IS LIFE? Attributes: Cellular organization Sensitivity (respond to stimuli) Growth (mitosis) Development Reproduction (meiosis) Regulation Homeostasis (Metabolism) Heredity (DNA & Transmission) WHAT ARE CELLS? Cell - basic unit of life Robert Hooke (1663) with microscope observed cork/leaf cells -coined term cells van Leeuvwenhoek (1673-1723) observed cells with microscope Schlieden (1838) observed plant cells Schwann (1839) observed animal cells Cell Theory: all living organisms are composed of cells (Schlieden & Schwann) Purkinje described protoplasm evolutionary history: 4.6-4.8 bya formation of earth 3.6 bya prokaryotes 1.6 bya eukaryotes 0.6 bya (600 mya) multicellular prokaryotes, eukaryotes organelle cytoskeleton plasma membrane cytoplasm, cytosol nucleus, nuclear envelope, nucleoplasm The Origin of Eukaryotic Cells endosymbiont, membrane invagination hypotheses symbiosis WHY ARE MOST CELLS SMALL? surface area to volume ratio Microscopes Windows into the Cell microscopy light microscope electron microscope CELL MEMBRANES plasma membrane Structure of Cell Membranes lipid bilayer model (Gorter & Grendel, 1925) fluid-mosaic model (Singer & Nicolson, 1972) hydrophobic, hydrophilic extrinsic, intrinsic proteins glycoproteins, glycolipids, glycocalyx Functions of Cell Membranes selective permeability + homeostasis : high K intracellular conc MOVEMENT ACROSS MEMBRANES Simple Diffusion dynamic equilibrium simple diffusion Facilitated Diffusion protein channels (pores) facilitated diffusion carrier protein no energy required goes with concentration gradient Osmosis osmotic pressure/ hydrostatic pressure isosmotic, hyperosmotic, hyposmotic tonicity, isotonic, hypertonic, hypotonic crenation Filtration filtration Active Transport active transport carrier protein requires energy goes against concentration gradient sodium-potassium-ATPase pump , calcium pump Endocytosis endocytosis pinocytosis vesicle phagocytosis, phagolysosome receptor-mediated endocytosis Exocytosis exocytosis CYTOPLASM, ORGANELLES, AND CELLULAR COMPONENTS Cytoplasm cytoskeleton cytosol (aqueous phase) Ribosomes: Protein Workbenches ribosomes messenger RNA (mRNA) polyribosomes (polysomes) Endoplasmic Reticulum: Production and Transport endoplasmic reticulum (ER) rough, smooth ER Golgi Apparatus: Packaging & Export Golgi apparatus (complex) cisternae transfer, secretory vesicles Lysosomes: Digestion and Degradation lysosomes acid hydrolases Mitochondria: Power Generators mitochondria mtDNA cristae, matrix Microtubules, Intermediate Filaments & Microfilaments: The Cytoskeleton microtubules tubulins intermediate filaments microfilaments myofibrils cytoskeleton Cilia & Flagella: Movement cilia, flagella axoneme (axial filament) dynein arms, spokes, basal body Centrioles: Specialized Microtubules centrioles Cytoplasmic Inclusions: Storage cytoplasmic inclusions THE NUCLEUS; INFORMATION CENTER Nuclear Envelope: Gateway to the Nucleus nuclear envelope, pores Chromosomes: Genetic Containers chromatin, chromosomes, genes Nucleolus: Preassembly Point for Ribosomes nucleolus WHAT IS ENERGY? energy work kinetic, potential energy thermodynamics kilocalorie (kcal), calorie THE LAWS OF ENERGY TRANSFORMATIONS matter mass First law of thermodynamics (conservation of energy) Second law of thermodynamics entropy ACTIVATION ENERGY activation energy catalysis, catalyst ENZYMES; BIOLOGICAL CATALYSTS enzyme, substrates Enzyme Structure active site induced fit Enzyme Function enzyme-substrate complex (ES) Factors Affecting Enzyme Activity denaturation COFACTORS AND COENZYMES cofactors, coenzymes nicotinamide adenine dinucleotide (NAD+) TROPHIC LEVEL – ENERGY FLUX primary producers primary consumers herbivore secondary consumers food chain decomposers metabolism, anabolism, catabolism ATP: THE CELL'S ENERGY CURRENCY adenosine triphosphate (ATP) adenine, ribose, phosphate high energy bond adenosine diphosphate (ADP), adenosine monophosphate (AMP) How Cells Trap Energy: An Overview substrate-level phosphorylation chemiosmosis cellular (oxidative) respiration aerobic respiration INTRODUCTION catabolism/anabolism reduction/oxidation reactions exogenic/endogeneric glycolysis aerobic, anaerobic fermentation GLYCOLYSIS: THE FIRST PHASE OF NUTRIENT METABOLISM glycolysis pyruvate (pyruvic acid) Evolutionary Perspective on Glycolysis Fermentation: ``Life Without Air'' fermentation anaerobic, facultatively anaerobic AEROBIC RESPIRATION: THE BIG ENERGY HARVEST aerobic respiration Krebs (citric acid ) cycle flavin adenine dinucleotide (FAD) electron transport chain The Energy Score for Oxidative Respiration: A Balance Sheet METABOLISM OF FATS AND PROTEINS: ALTERNATIVE FOOD MOLECULES lipase catabolism of amino acids/proteins = deamination reaction + NH3/ NH4 1amine gourp very toxic; aquatic organisms Urea 2 amine groups less toxic; mammals & amphibians uric acid: 4 amine groups least toxic; insects, birds, reptiles INTRODUCTION sexual reproduction cell division MITOSIS, CYTOKINESIS, AND THE CELL CYCLE: AN OVERVIEW mitosis cytokinesis interphase cell cycle (Figure 6.1) G1 (first gap), S (DNA synthesis), G2 (second gap), M (mitotic) phases of cell cycle INTERPHASE: PARTITIONING THE HEREDITARY MATERIAL interphase (G1, S, G2 phases) replication chromatid, sister chromatids centromere, kinetochore condensation PHASES OF MITOSIS prophase, metaphase, anaphase, telophase Prophase: Formation of the Mitotic Apparatus chromo somes condense = visible nuclear envelope fragmentsà contained in vesicles centrioles aster microtubule fibers mitotic spindle apparatus Metaphase: Separation of Sister Chromatids chromosomes aligned along the metaphasic plate Anaphase: Movement of the Chromosomes centromeres divide sister chromatids split Telophase: Reformation of Nuclei cleavage appears chromosomes reach the opposite poles vesicles containing nuclear fragments reappear CYTOKINESIS: PARTITIONING THE CYTOPLASM cytokinesis contractile ring cleavage furrow CONTROL OF THE CELL CYCLE Maturation Promoting Factor (cyclin) Regulatory genes EUKARYOTIC CHROMOSOMES chromatin Heterochromatin and Euchromatin inactive (heterochromatic) regions active (euchromatic) regions Organization of DNA and Protein histone proteins nucleosome Sex Chromosomes and Autosomes sex chromosomes, autosomes X-O, X-Y system (of sex determination) Number of Chromosomes diploid, CHANGES IN CHROMOSOME NUMBER AND STRUCTURE Detecting Number and Structure Changes karyotyping DNA: THE GENETIC MATERIAL The Double-Helix Model deoxyribonucleic acid (DNA) ribonucleic acid (RNA) molecular genetics Nucleic-Acid Structure purine, pyrimidine adenine, guanine, cytosine thymine, uracil deoxyribose, ribose antiparallel CONTROL OF GENE EXPRESSION IN EUKARYOTES structural genes regulator genes