BSC 2010 Test 1 Study GuideLecture 1• New Properties Emerge at Each Level of Hierarchyo Life can be studied by level Ex: Atom → Molecule → Biosphereo Study of Life can be organized at different levels of biological organizations• Emergent Propertieso Result from the arrangement and interactions of parts in a systemo Methods to study Emergent Properties: 1. Reductionism – reducing a complex system to its simplest component• Makes it Manageable• Ex: Understanding DNA Structureo Developed by Watson, Crick, and Franklin in 1954 2. Systems Biology – viewing an entire system as a whole and how they function together• Construct models for dynamic behavior of entire biological systems• Cellso Definition: Organism’s basic structure and function unito Lowest level of lifeo All cells have a membrane and use DNA for genetic information• Components Required for Lifeo 1. Homeostasis – ability to maintain internal environmento 2. Organization – structurally composed of at least one cello 3. Metabolism – ability to transform energyo 4. Growth – maintenance of a higher rate of anabolism (building up) than catabolism (breaking down)o 5. Adaption – ability to change over timeo 6. Response to Stimulio 7. Reproduction – ability to form new organisms Most important aspect of life• Cell Types (2)oo 1. Prokaryotic Simple Cells without nucleus and membrane covered organelles• Ex: Bacteriao 2. Eukaryotic Membrane enclosed organelles• Ex: Plants and animals•• Continuity of Lifeo Based on inheritable info in the form of DNA Chromosomes contain the majority of DNA and are found in the nucleuso DNA is the substance of genes and build proteinso Genes – units of inheritance that transmit info that pass from parent to offspring Cells differentiate by using specific sections of the DNA• Central Dogma of Modern BiologyoDNA ⟹ RNA ⟹ Proteino↑↑o Transcription Translation• Structure of DNAo Shape: Double Helixo Nucleotides: A, T, C, G Vary arrangement to create new cellso 1 % - 2 % of DNA codes for proteins • Biology – study of lifeo Two Ways to Study 1. Discovery Science – observe and describe aspects of the world and draw conclusions from inductive reasoning 2. Hypothesis Based Science – from observations, scientists propose hypotheses and if they are correct it can be tested to determine an outcomeLecture 2• Mattero Definition: Anything that takes up space and has masso Made of pure chemical elements Compounds – combinations of 2 or more elements in a fixed ratioo Makes up all organisms• Elemento Definition: substance that cannot be further broken down chemicallyo Essential Elements of Life: Consists of 25 elements • Carbon, hydrogen, nitrogen, and oxygen make up 96 % of all lifeo Most of remaining 4 % is calcium, phosphorus, potassium, and sulfur• Trace Elements – required in small amounts (less than 100 mg daily)• Elemental Properties o Depend on atom structure All elements are made of atoms Atom – smallest unit of matter that retains properties of elements• Made of subatomic particlesParticle Charge Mass LocationProton + 1 Dalton Atomic NucleusNeutron No Charge 1 Dalton Atomic NucleusElectron - 0 Electron Cloud• Periodic Table1st Shell1HydrogenH↑ Electronegativity →2HeliumHe2nd Shell3LithiumLi4BerylliumBe5BoronB6CarbonC7NitrogenN8OxygenO9FluorineF10NeonNe3rd Shell11SodiumNa12MagnesiumMg13AluminumAl14SiliconSi15PhosphorusP16SulfurS17ChlorineCl18ArgonAr 2 Atomic Number He Element Symbol 4.00 Atomic Masso First shell can hold a maximum of 2 electronso Second and Third shells can each hold a maximum of eight electronso All elements in the first column have one electron in their valence (outer) shell All elements in column two have two electrons in their valence shell• Elements in column three have three electrons and so on• Isotopes o Atoms of the same element with different numbers of neutronso Radioactive Applications: Carbon Dating Diagnosing Medical Disorders Tracing Atoms in Metabolic Processes • Energyo Capacity to cause change Potential Energy – energy due to location and structureo As shell level increases energy levels increase Due to electrons in higher shells having higher energyo Energy is lost (emitted) when electrons drop down in shells Energy is absorbed when electrons increase in shell level• Electron Distributiono Chemical behavior of atoms are determined by how electrons are arranged in shells Illustrated by the periodic tableo Valence Electrons – e- present in outer most shell (valence shell) Valence shell electrons react and determine the chemical behavior of an element Chemically Inert – Full valence shell makes elements unreactive• Electronegativity – element’s tendency to take electronso Oxygen is the most electronegative element of lifeo Carbon is the best sharer of electrons “The Ultimate Sharer”• Bond Types (2)o 1. Covalent Bond – equal sharing of valence electrons 2 Types:• Nonpolar Covalent Bond – completely equal sharing of electronso Ex: H2, CH4• Polar Covalent Bond – unequal sharing of electrons resulting in partial positive and negative chargeso Ex: H2O The two hydrogen atoms have a partial positive charge and the oxygen has a partial negative charge because of its high electronegativityo Partial Charge – more electronegative atom keeps more electrons around it−¿(∂ Negative Charge)δ¿oo Polar Easily broken bonds Releases less energy Ex: Carbso Nonpolar Harder to break Releases more energy Ex: Hydrocarbon•o 2. Ionic Bond – forms ions (charged particles) due to the complete division of electrons Ex: −¿+¿+Cl¿HCl→ H¿Lecture 3• Watero Appears to be unique to Earth Required for Lifeo Covers ¾ of Earth’s surface o Makes up 60 % - 70 % of weight of all life o Regenerated and redistributed by the water cycleo Only molecule that exists naturally in all three states (solid, liquid, gas)• Structure of Watero Chemical Formula: H2Oo Bond Angle = 104.5oo Figure:Hd+ Hd+ \ / Od- Forms of Water (3)o 1. Solid: Ice Hydrogen bonds are stable Forms a Hexagonal Lattice More spacious than liquid form (less dense)o 2. Liquid Fragile and disorganized hydrogen bonds• Bonds last a few trillionths of a secondo 3. Gas Single
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