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Chemistry of Life- Nature of Matter

Chemistry of Life- Nature of Matter. Pre-AP Biology Mrs. Horstmann Fall 2009. Objective:. What is matter?. What is matter? Matter is just stuff. Matter - takes up space and has mass All matter is composed of basic elements:

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Chemistry of Life- Nature of Matter

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  1. Chemistry of Life- Nature of Matter Pre-AP Biology Mrs. Horstmann Fall 2009

  2. Objective:

  3. What is matter?

  4. What is matter? Matter is just stuff • Matter- takes up space and has mass • All matter is composed of basic elements: • A chemical element is a pure substance that consists of only one type of atom • Elements cannot be broken down • Elements are represented on the periodic table by their atomic number

  5. Atoms- smallest unit of matter that cannot be broken down by chemical means • made up of protons, neutrons and electrons • protons= positive charge • neutrons= no charge • electrons= negative charge • opposites attract • negative charges are attracted to positive charges • atoms consist of mostly empty spaces

  6. Neutrons (no charge) and protons (positive charge) are in the nucleus • Electrons (negative charge) move around outside the nucleus in the electron cloud. • you can only have 2 electrons on first energy level • there can be up to 8 electrons on the rest of the levels

  7. Chemical bonding • Valence electrons- electrons in the outermost electron shell. They are responsible for bonding. Bonds contain energy. • Atoms want eight electrons in their outer shell because it makes the atom stable

  8. Compounds- substances made of the joined atoms of two or more different elements • Ex: Na and Cl form table salt

  9. Types of Bonding 1. Covalent bonding- two or more atoms share electrons to form a molecule (group of atoms) • Fill or empty the outer shells of the atoms involved in the bond • Relatively strong bonds, harder to “break” 2. Hydrogen bond- a chemical attraction between polar molecules • H20= the electrons are more attracted to the 0 than the H • Individually the bonds are weak, but in large quantities the bonds are stronger

  10. Ionic bonds- involves the transfer of electrons; one atom loses electrons and the other gains • Opposite charged ions are attracted to each other • Clˉ is attracted to Na+ to make NaCl • Relatively weak bonds that disassociate in water, producing a solution • Ion- an atom that gains or looses an electron

  11. H20

  12. NaCl

  13. Water and Solutions • Properties of Water: • Cohesion: Water is attracted to other water molecules • Surface Tension: name we give to the cohesion of water molecules at the surface of a body of water.

  14. Polarity • Each H atom is covalently bonded to an O atom via shared electrons • O also has two unshared pairs of electrons surrounding the oxygen atom • There is an uneven distribution of electron density: a partial negative charge near the oxygen atom (b/c of the extra electrons) and a partial positive charge near the hydrogen atoms • Forms hydrogen bonds with other water molecules • ionic compounds dissolve best in water

  15. Solutions- one or more substances are evenly distributed in another substance • Important in body; blood, sugar • Water molecules are strong but can break Hydroxide ion H20  H+ + OH Hydrogen ion

  16. Acids- compounds that form hydrogen ions when dissolved in water • Releases H+ • Bases- compounds that form hydroxide ions when dissolved in water • accept H+ • pH concentration- based on the concentration of hydrogen ions in solution • pure water has a value of 7 • acidic solutions have a pH below 7 • basic solutions have a pH above 7

  17. Carbon (Organic) Compounds • Carbohydrates- compounds of life made of C, H and O in a 1:2:1 ratio • Monosaccharides: single sugar • Polysaccharides: many monosaccharides • Importance of Carbohydrates to life • main energy source of all cells- glucose (C6H12O6) • energy storage in plant cells- starch • energy storage in animal cells- glycogen • cell walls of plants- cellulose

  18. Lipids- compounds of life made of lots of C & H (fats, oils, waxes) • Most lipids do not dissolve well in water (covalent bonds) • Importance of lipids to life: • long term energy storage • provide structure of cell membranes • chemical messengers: steroids like estrogen, testosterone, and cholesterol.

  19. Proteins- Compounds of life made of nitrogen, C, O and H • Amino Acids: building blocks of proteins • Importance of proteins to life: • body structure: muscles, bone, collagen, cartilage, hair • transport: hemoglobin- red chemical in blood to transport oxygen • fight diseases: antibodies • control chemical reactions: enzymes

  20. Nucleic Acids- Nucleotides- composed of a sugar, a base and a phosphate • Importance of nucleic acids to life: • store and move hereditary or genetic information within all cells • DNA- two strands that spiral around each other • stores hereditary information

  21. RNA- one single strand • manufactures proteins • acts as an enzyme • ATP- single nucleotide with two extra energy storing phosphate groups (stores energy temporarily)

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