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Chapter2a
 

Chapter2a

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    Chapter2a Chapter2a Document Transcript

    • Why Chemistry??? • Chemistry is everywhere, especially Chapter 2: within the human body Chemistry • Chemistry drives biological processes Comes Alive • We are composed of chemicals (water, protein, fat, DNA, etc) and the substances we ingest are chemicals as well 1 2 Structural Organization: Basic Chemistry: Matter Chemical Level • Chemistry is the study of the composition of matter and how this • Atoms/ Elements composition changes through chemical reactions • Matter is anything that occupies space • Molecules/ and has mass Compounds • Matter exists in solid, liquid, and gaseous states • Macromolecules • Within the body, all states or matter are 3 evident 4 Basic Chemistry: Energy Forms of Energy • Energy is the capacity to do work or • Chemical: Stored in chemical bonds to put matter into motion (ex: ATP) • Kinetic Energy = energy in action • Electrical: From the movement of • Potential Energy = stored energy charged particles (ex: nerve impulses) • Energy form conversions: 1st law of • Mechanical: Energy directly involved in thermodynamics… moving matter (ex: muscular contraction) “Neither matter nor energy can be • Radiant/ Electromagnetic: Energy that created or destroyed” 5 travels in waves (ex: Light, UV, X-rays)6 1
    • Composition of Matter Atomic Structure • All matter is Subatomic Characteristics composed of Particle elements Proton + charge, large • Each element is particle, in nucleus composed of atoms Electron - charge, small • Each element is has particle, around unique physical & nucleus chemical properties Neutron No charge, • Most important for the large particle, body = CHNOPS 7 in nucleus 8 Atoms of Elements Chemical Bonding • e- are arranged in shells & orbitals • Valence shell electrons affect the reactivity of atoms • Atomic Number = p+ • Octet rule • p+ = e - • Mass Number = p+ + no 9 10 Molecules & Compounds Ionic Bonds • Molecules = two or more chemically bound atoms • Two or more atoms of the same element (ex: H2, O2) = molecule of an element • Two or more atoms of different elements • e- can transfer & result in ion (charged) formation (ex: H2O, NaCl) = molecule of a compound • Anions: Negatively charged ion, e- acceptor (Cl-) • Cations: Positively charged ion, e- donor (Na+) • Since opposites attract, the atoms stay close 11 together 12 2
    • Covalent Bonds Polarity • Nonpolar Covalent Molecules: – Have equal e- pair sharing – Charge is balanced among atoms • Polar Covalent Molecules: – Unequal sharing of e- • e- are shared in order to fill valence shells part-time – Slight (–) charge on one • Covalent bonds involve a shared orbital end, slight (+) charge on 13 another 14 Hydrogen Bonds Chemical Reactions • Chemical equations symbolize chemical • Occur when reactions covalently bonded H atoms are weakly • Components: Products & Reactants attracted by other • Synthesis: A + B  AB atoms • Decomposition: AB  A + B • Not a true bond but is • Exchange: AB + C  AC + B a weak attraction AB + CD  AD + CB • Important for DNA structure • Some reactions are reversible A+B AB 15 16 Examples Factors Affecting Reaction Rates • Temperature: • Particle Size: Increased = Faster Small = Fast Decreased = Slower Large = Slow • Reactant • Catalysts: Concentration: Present = Fast High = Faster Absent = Slow Low = Slow 17 18 3
    • Biochemistry Inorganic Compounds: Water • Biochemistry: The study of the • Most abundant cellular chemical composition and reactions of component living matter • High heat capacity • Inorganic Compounds: All compounds • High heat of vaporization that do not contain carbon (water, • Universal solvent • Forms hydration layers oxygen, salts) • Transports biochemicals • Organic Compounds: All compounds • Reactive that contain carbon (carbohydrates, • Cushions lipids, proteins, nucleic acids) 19 20 Inorganic Compounds: Salts Inorganic Compounds: Acids & Bases • Ionic compounds that do • Acids: Donate (release) H+/ protons not contain H+ or OH- – When dissolved in water, acids release H+ and • In water, dissociate into an anion ions/ electrolytes HCL  H+ + Cl- • Ions are essential for: • Bases: Accept H+, commonly contain OH- – Nerve impulse – When dissolved in water, bases release OH- transmission (Na, K) and a cation. The OH- ion then immediately – Muscle contraction (Na, accepts H+ to form water K) NaOH  Na+ + OH- – Hemoglobin in blood (Fe) OH- + H+  H2O 21 22 pH Scale Inorganic Compounds: Buffers • Measures H+ ion • Buffers: Chemicals that resist abrupt pH concentrations changes • Acidic: – Function by donating H+ when needed and by accepting H+ when in excess [H+] > [OH-], pH= 0-6 – Very, very important for biological systems!!! • Neutral: Rising pH [H+] = [OH-], pH= 7 H2CO3 HCO3- + H+ • Basic/ Alkaline: weak acid Drop in pH weak base Proton H+ Donor H+ Acceptor [H+] < [OH-], pH= 8-14 23 24 4
    • Organic Compounds Building & Breaking Organic Compounds • Molecules unique to biological systems – Carbohydrates – Lipids (fats) – Proteins – Nucleic Acids (DNA & RNA) • Monomer, Dimer, Polymer 25 26 Polymerization • Chain-like molecules composed of monomeric units • Continuous dehydration synthesis can grow polymer chains 27 5