chapter 2

  1. Define Matter
    anything that takes up space and has mass
  2. Define Atoms
    smallest chemical units of matter
  3. Atomic Structure
    • electrons: negatively charged subatomic particles circling a nucleus
    • nucleus: structure containing neutrons and protons
    • neutrons: uncharged particles
    • Protons: positively charged particles
  4. Atomic Structure:
    Atomic Number
    Atomic Mass
    • Element: composed of a single type of atom
    • Atomic Number: equal to the number of protons in the nucleus. change in number means change in element.
    • Atomic mass: sum for the masses of protons, neutrons and electrons
  5. Isotopes
    • Carbon-13 and carbon-14
    • Atoms of a given element that differ in the number of neutrons in their nuclei
    • carbon-13 is stable
    • carbon-14 is unstable; release energy during radioactive decay
  6. What determines the atoms chemical behavior?
    • Electrons. only electrons of atoms interact
    • electrons occupy electron shells
  7. Valence electrons
    electrons in the outermost chell that interact
  8. Valence
    • combining capacity of an atom.
    • -positive if it has electrons to give up
    • -negative if it has electrons to give up
    • -stable when outer electron shells contain eight electrons
  9. Chemical bonds
    atoms combine by sharing or transferring valence electrons
  10. molecule
    two or more atoms held together by chemical bonds
  11. compound
    a molecule composed of more than one element
  12. electronegativity
    • attraction of atom for electrons
    • -the more electronegative an atom the greater the pull it's nucleur exerts on electrons
  13. 4 types of Chemical Bonds
    • Nonpolar covalent: equal sharing, not electronegative
    • Polar Covalent: electronegative, unequal sharing. angeled
    • Ionic Bond: no sharing. electrons are given up making the element an ion, completely positive, cation or completely negative, anion
    • Hydrogen Bond: weak bond of water.
  14. Nonpolar covalent bonds
    • shared electrons spend equal amounts of time around each nucleus
    • atoms with similiar electronegativities
    • no poles exist
    • carbon atoms form four non polar covalent bonds with other atoms
    • organic compounds contain carbon and hydrogen atoms
  15. Polar Covalent Bonds
    • Unequal sharing of electrons due to signicantly different electronegativities
    • Most important polar covalent bonds involve hydrogen -Allow for hydrogen bonding
  16. Ionic Bonds
    • Occur when two atoms with vastly different electronegativities come together
    • atoms have either positive (cation) or negative (anion) charges
    • cations and anions attract eachother and form ionic bonds (no electrons shared)
    • typically form crystalline ionic compounds known as salts
  17. Hydrogen Bonds
    • Weak forces that combine with polar covalent bonds
    • electrical attraction between partially charged H+ and full or partial negative charge on same or different molecule
    • eaker than covalent bonds but essential for life
    • many help to stabilize 3-D shapes or large molecules
  18. Chemical Reactions
    • The breaking or making of chemical bonds
    • involve reactants and products
    • biochemistry involves chemical reactions of living things
  19. Define reactant
    atoms, ions or molecules that exist at the begining of a reaction.
  20. Synthesis reactions (creating)
    • Involve the formation of larger, more complex molecules
    • reactant + reactant = product
    • require energy (endothermic)
    •  Most common type is dehydration synthesis -water molecule is formed
    • all the synthesis reactions in an organism are called anabolism
  21. Decomposition Reactions
    • Break bonds with larger molecules to form smaller atoms, ions, and molecules
    • release energy(exothermic)
    • Product = reactant + reactant 
    • most common type is hydrolysis
    • ionic components of water are added to products
    • all the decomposition reactions in an organism are called catabolism
  22. Exchange Reactions
    –Involve breaking and forming covalent bonds, and involve endothermic and exothermic steps

    • –Involve atoms moving from one molecule to another
    • Sum of all chemical reactions in an organism is called metabolism
  23. Water
    • –Most abundant substance in organisms
    • –Most of its special characteristics due to two polar covalent bonds
    • –Cohesive molecules
    • – surface tension
    • –Excellent solvent
    • –Remains liquid across wide range of temperatures
    • –Can absorb significant amounts of energy without changing temperature
    • –Participates in many chemical reactions
  24. Acids and Bases
    • –Dissociated by water into component cations and anions
    • –Acid – dissociates into one or more H+ and one or more anions
    • –Base – binds with H+ when dissolved into water; some dissociate into cations and OH
    •  –Metabolism requires relatively constant balance of acids and bases
    • –Concentration of H+ in solution expressed using the pH scale
    • –Buffers prevent drastic changes in internal pH
  25. pH scale
    • 0-6 is acidic increasing amts of H+
    • 7 is neutral
    • 8-14 is basic increasing amts of OH-
    • change in # is an increase of base 10    
  26. Salts
    • –Compounds that dissociate in water into cations and anions other than H+ and OH–
    • –Cations and anions of salts are electrolytes
    • –Create electrical differences between inside and outside of cell
    • –Transfer electrons from one location to another
    • –Form important components of many enzymes
  27. Organic Macromolecules
    • – large molecules used by all organisms
    • Functional groups
    • Lipids
    • Carbohydrates
    • Protiens
    • nucleic acids
    • –Monomers – basic building blocks of macromolecules
  28. Functional Groups
    • –Contain carbon and hydrogen atoms
    • Atoms often appear in certain common arrangements – functional groups
  29. Lipids
    • –Not composed of regular subunits, but are all hydrophobic because they are all carbon and hydrogen and all nonpolar.
    • –Four groups: Fats, Phospholipids, Waxes, Steroids
    • - Sterols maintain fluidity
  30. fats
    • made by organisms via dehydraton synthesis that form esters between the 3 chains and an alcohol, glycerol.
    • three fatty acid chains attached to a glycerol (triglycerides)
    • saturated: each C molecule is bound to two H molecules
    • unsaturate: one or more C atoms is attached to another C atom.
    • Polyunsaturated: if several C atoms are bound.
    • Abundant energy is stored in C-C covalent bonds.
  31. Phospholipids
    • similiar to fats but two fatty acid chains and one phosphate.
    • phosphate head is polar and hydrophilic.
  32. Waxes
    • 1 long fatty acid chain and 1 long alcohol chain. completely water insoluable.
    • mycobacterium tuberculosis surrounded by a waxy wall.
  33. Steroids
    • 4 rings consisting of 5 or 6 C each, fused together and attached to various side chains.
    • play many roles in human motabilism, some act as hormones.
    • Fungi, plants and mycoplasm use sterol to mantain fluidity at low temperatures
  34. Carbohydrate definition and Functions 6
    • –Organic molecules composed of carbon, hydrogen, and oxygen (CH2O)n
    • –Functions
    • –Long-term storage of chemical energy
    • –Ready energy source
    •  –Part of backbones of nucleic acids
    • –Converted to amino acids
    • –Form cell wall
    • Involved in intracellular interactions between animal cells
  35. –Carbohydrate Types
    • –Monosaccharides: simple sugars 
    • Disaccharides: 2 monosaccharides are linked together via dehydration synthesis 
    • –Polysaccharides: polymers of 10s-1,000s of monosaccharides that are covalently linked via dehydration synthesis
  36. Protiens
    • Polymers composed of monomers called amino acids
    •  –Mostly composed of carbon, hydrogen, oxygen, nitrogen, and sulfur
    • –Functions: Structure, Enzymatic catalysis, Regulation, Transportation and Defense and offense
    • Structures:primary, secondary, tertiary (3D shape), quanternary
  37. List the 5 functions of Protein
    • Structure: cell walls. membranes, hair, skin, nails, muscles, flagella, cilia etc
    • Enzymatic Catalysis: enhace the speed or liklihood of  a chemical reaction
    • Regulation: regulate cell function ie: hormones
    • Transportation: channels and pumps
    • Defense and offense: antibodies, complement, bacteriocins     
  38. Describe the 4 structures of protein
    • Primary:sequence of amino acids in a polypeptide chain
    • Secondary: interaction between regions of the polypeptide resulting in a helix or pleated sheet, hydrogen bonding
    • Tertiary: continued hydrogen bonding and covalent bonding. 3D shape
    • Quaternary: more than one polypeptide chain
  39. Amino Acids
    • –The monomers that make up proteins
    • –Most organisms use only 21 amino acids in the synthesis of proteins
    • –Side groups affect how amino acids interact with one another and how a protein interacts with other molecules
    • –A covalent bond (peptide bond) is formed between amino acids by dehydration synthesis reaction
  40. Stereoisomers
    molecules that are mirror images of eachother
  41. Nucleic Acids
    • –DNA and RNA: the genetic material of organisms
    • –RNA also acts as enzyme, binds amino acids, and helps form polypeptides
  42. Nucleic Acids: Nucleotides
    • –Monomers that make up nucleic acids (DNA/ RNA) 
    • –Composed of three parts :
    •             Phosphate,
    •             Pentose sugar:deoxyribose or ribose
    •             One of five cyclic nitrogenous bases
    •                      Adenine
    •                      Guanine
    •                      cytosine
    •                      thymine or Uracil
  43. Nucleic Acid Structure
    • –Three H bonds form between C and G
    • –Two H bonds form between T and A in DNA or between U and A in RNA
    • –DNA is double stranded in most cells and viruses
    • –Two strands are complementary and antiparallel
  44. Nucleic Acid Function
    • –DNA is genetic material of all organisms and of many viruses
    • –Carries instructions for synthesis of RNA and proteins; controls synthesis of all molecules in an organism
Card Set
chapter 2
chapter 2