1 / 28

Chemistry of Life

Chemistry of Life. Chapter 2. An Intro to Chemistry. Matter. Any substance that has mass and takes up space Composed of 1 or more elements Found in 1 of 3 states Gas – no definite shape or volume Liquid – shape conforms to container Solid – definite shape. Elements. Human.

nolan-moore
Download Presentation

Chemistry of Life

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemistry of Life Chapter 2

  2. An Intro to Chemistry

  3. Matter • Any substance that has mass and takes up space • Composed of 1 or more elements • Found in 1 of 3 states • Gas – no definite shape or volume • Liquid – shape conforms to container • Solid – definite shape

  4. Elements Human Oxygen 61.0% Carbon 23.0 Hydrogen 10.0 Nitrogen 2.6 Calcium 1.4 Phosphorus 1.1 Potassium 0.2 Sulfur 0.2 96% • Substances that can’t be broken down by ordinary chemical processes • 92 occur naturally on Earth • About 25 are essential to life • 96% of human body, as well as other living organisms, from 4 elements (CHON) • Composed of atoms • 2+ of same atoms is a molecule (O2) • 2+ of different atoms is a compound (NaCl, H2O) • Metal + poisonous gas = edible product • Gas + gas = liquid

  5. Atoms • Smallest particles that retain the properties of an element • Made up of subatomic particles: • Protons (+) in nucleus • Electrons (-) orbits nucleus • Neutrons (no charge) in nucleus • Protons and neutrons • Mass of about 1 dalton (atomic mass unit, amu) • Electrons • Mass is negligible (1/2000 amu)

  6. Reading A Periodic Table • Elements differ depending on the number of subatomic particles • Atomic symbol • 1st letter or 2 (usually) • Atomic number • Determined by number of protons • Neutral atoms contain equal # of electrons • Element specific • Mass number • Determined by number of protons + neutrons • Atomic weight: average of relative weights of all isotopes, versions of the element

  7. The Periodic Table Most Common Elements in Living Organisms

  8. Chemical Bonds • Energy relationship between electrons • Energy is the capacity to do work, cause change, or move matter • Kinetic: energy of motion • Potential: energy due to location or structure; capability • Electrons repel one another (magnets), but attracted to protons (opposites attract) • Determine chemical properties, reactivity, of atoms • Orbitals are key • Closer to the nucleus = lower energy and filled first • Octet rule: hold up to 8 electrons (not 1st = 2) • Outermost is valence shell • Chemical reactions are making and breaking bonds

  9. Electron Shell Models • Inert versus reactive elements • Valence electrons

  10. Ionic Bonds cation anion • One atom loses electron(s) to become _____ charge? • Another atom gains these electrons to become _____ charge? • Charge difference attracts the two ions to each other • Clinically called electrolytes • Very weak bond • E.g. Salts

  11. Covalent Bonds • Atoms share a pair(s) of electrons to fill valence shell • Form single, double, or triple covalent bond, based on number of electrons shared • Strong bonds

  12. What’s Mine is Yours or Just Mine Nonpolar molecules Polar Molecules • Electrons shared equally • Example: carbon dioxide(CO2) • Electrons spend more time near the nucleus with the most protons (electronegativity) • Example: water (H20)

  13. Hydrogen Bonds • Special case of covalent bonds • Attractions between molecules • Polar hydrogen (slightly ‘+’ charge) attracted to another polar molecule (slightly ‘-’ charge) • Hold large molecules in a specific 3D shape

  14. Chemical Reactions • Chemical equation: reactant(s) + reactant(s) = product(s) • May be reversible • Move to equilibrium • Types • Synthesis: (A + B  AB) usually anabolic and endergonic • Decomposition: (AB  A + B) usually catabolic and exergonic • Exchange: (AB + CD  AD + BC) may or may not be endergonic/exergonic • Redox: may gain or lose electrons • Oxidized – loses electrons (LEO) • Reduced – gains electrons (GER) • Affected by temperature, concentration, catalysts, etc.

  15. An Intro to Biochemistry

  16. Biologically Important Compounds • Inorganics lack carbon (generally) • E.g. salts, water, acids, and bases • Organics contain carbon, are covalently bonded, and generally large • E.g. carbohydrates, lipids, proteins, and nucleic acids

  17. Properties of Water • Temperature-stabilizing effects • Absorbs and releases large amounts of heat w/o significant change • Sun, wind, muscle activity • High heat of evaporation • Absorption of heat breaks bonds; liquid  gas • Sweating • Polar molecule • Hydrophobic and hydrophilic • Solvent/solute relationship • Blood circulation, waste disposal, and cleaning • Reactivity • Hydrolysis and dehydration reactions

  18. Electrolytes • Ions able to conduct electrical current • Kidneys regulate • Salts contain ions other than H+ or OH- • E.g. NaCl, CaCO3, and calcium phosphates • Acids are hydrogen ion (H+) donors • Concentration determines acidity of a solution • E.g. pH < 7; HCl, H2CO3 • Bases are hydrogen acceptors • Form water upon disassociation • E.g. pH > 7; Mg(OH) 2, HCO3-, and NH3 • Buffers release H + with increasing pH and accept H + when decreasing • H2CO3HCO3- + H+

  19. Building Organic Molecules • Monomers: small repeating units • Universal, similar in all forms of life • Polymers: chains of monomers, functional components of cells (macromolecules) • DNA is composed of 4 monomers (nucleotides) • Variation based on arrangement • Proteins from 20 different amino acids (AA’s) • Variation distinguishes within and between species

  20. Making and Breaking Polymers Dehydration reaction Hydrolysis reaction • Links monomers • Loss of water for each monomer added • Forms a covalent bond • Breaks polymers • Addition of water for each broken bond 1 2 4 3 4 1 2 3 1 4 2 3 1 2 3 4

  21. Carbohydrates • General (CH2O)n ratio, end in ‘ose’ • Fuel source for cells • Glycosidic bonds • Dehydration vs. hydrolysis • Monosaccharides (simple) • Pentoses: ribose and deoxyribose • Hexoses: glucose, fructose, & lactose (energy production) • Disaccharides (simple) • Maltose, lactose (glu + gal), & sucrose (glu + fru) • Polysaccharides (complex) • Glycogen (animal storage) • Starch (plant storage)

  22. Lipids • Composed of fatty acids (long carbon chains) and a glycerol (3 carbons) • Triglycerides • 3 FA’s • Most usable form of energy • Fats (animal) and oils (plants) • Saturated or unsaturated (mono- or poly-) • Phospholipids • 2 FA’s and a phosphate group • Amphipathic molecule • Cell membranes • Steroids • Hydrocarbon rings • Cholesterol and sex hormones • Eicosanoids • In all cell membranes • Prostaglandins role in blood clotting, inflammation, and labor contractions

  23. Proteins • Chains of amino acids joined by peptide bonds • 20 different types (alphabet) • Peptide, polypeptides, and proteins (words) are all slightly different • Structural levels • Primary (1°) – sequence of amino acids • Secondary (2°) – primary level folds to form alpha (α) – helixes and beta (β) - pleated sheets • Tertiary (3°) – folding of secondary structures on each other • Quaternary (4°) – 2+ polypeptides interact to form a protein • Denaturation destroys structure which alters or inhibits function • Changes in pH and temperature • Reversible or permanent depending on extend of change (fevers)

  24. Protein Types • Fibrous (structural proteins) • Building materials of the body • Keratin, elastin, and collagen • Movement • Globular (functional proteins) • Enzymes • Transport • Immunity

  25. Enzymes • Globular proteins acting as catalysts to speed a reaction • Lower energy of activation (EA) • End in ‘ase’ and named for substrate • Mechanism of enzyme action: • Enzyme binds substrate at its active site on the enzyme. • Enzyme-substrate complex undergoes an internal rearrangement that forms a product. • Product released and now catalyzes another reaction

  26. Nucleic Acids • DNA and RNA • Composed of nucleotides with 3 components • Pentose sugar • Phosphate group (PO4) • Nitrogenous base form complementray pairs • Purines (2 rings): adenine (A) and guanine (G) • Pyrimidines (1 ring): thymine (T), cytosine (C), and uracil (U)

  27. How DNA and RNA Differ DNA (deoxyribonucleic acid) RNA (ribonucleic acid) • Directs protein synthesis; replicates self; genetic material • Sugar is deoxyribose • Has –H • Bases are A,C, G, and T • Double-stranded helix • Only in nucleus • 1 type • Carries out protein synthesis • Sugar is ribose • Has -OH • Bases are A, C, G, and U • Single-stranded • Not confined to nucleus • 3 major types

  28. Adenosine Triphosphate (ATP) • RNA nucleotide with 3 phosphate groups • Stores energy from break down of glucose • Transfers phosphate groups to release energy, phosphorylation • Controls energy release

More Related