BIO 330 Lecture Notes - Lecture 13: Differential Interference Contrast Microscopy, Scanning Electron Microscope, Transmission Electron Microscopy
BIO 330 Lecture notes 13:
• Robert Hooke
• -first scientist to observe cork cells (NOT alive)
• -called them cells because they reminded him of monk's rooms in a monastery
• Antonie van Leeuwenhoek
• -observed LIVING organisms from pond water (algaea and protozoa); called them
animacules
• -discovered bacteria on his teeth and squamous cells in the mouth (first representations of
human cells)
• Shielden and Shwaan
• 1838- all plants are made up of cells
• 1839- all animals are made up of cells
• Rudolf Virchow
• 1855- concluded that cells come from preexisting cells
• Cell Theory
• All organisms consist of one or more cells
• Cells arise from other cells
• Cells are the basic units of structure and reproduction
• Cytology
• study of cell structure using optical techniques (microscopes)
• Light Microscopy
• uses sunlight or artificial light (0.2micron-2mm)
• bright field microscopy
• phase-contrast microscopy
• Differential interference contrast microscopy
• fluorescence microscopy
• confocal microscopy
• electron microscopy
• uses electrons (0.2 nanometer- 100micron)
• -scanning EM
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• -transmission EM
• Scanning Electron Microscopy (SEM)
• scans the surface by deflecting electrons
• Transmission Electron Microscopy (TEM)
• transmits electrons through a specimen to form an image
• Immunocytochemistry
• when a fluorescent tagged antigen binds to a specific molecule, making a protein visible
• A model organism is a species that
• has been widely sudied
• well characterized
• easy to manipulate
• has particular advantages
• Are covalent or noncovalent bonds easier to break?
• noncovalent are easier to break
• Ultraviolet light
• can break carbon bonds (unlike visible light and infrared light)
• Hydrocarbons
• -not soluble in carbon
• -important in the biological membrane (tails of phospholipids)
• Stereoisomers
• mirror images that are not superimposable
• A compound with n asymmetric carbons will have how many stereoisomers?
• 2^n
• What causes the dipole in H2O?
• electronegative oxygen pulling the electrons towards it
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• Hydrogen bonds vs covalent bonds
• h bonds are 1/10 as strong
• vast number of hydrogen bonds in water leads to
• high heat of evaporation
• high specific heat
• high boiling point
• high surface tension
• Why is water an excellent solvent?
• polarity and it can form ionic and hydrogen bonds with solutes
• Cells contain 3 different kinds of macromolecules
• proteins
• nucleic acids
• polysaccharides
• Polymerization process
• monomer gets activated by connecting to a carrier molecule (ATP driven reaction)
• Addition of each monomer occurs via condensation reaction
• polymerization has directionality
• Molecular chaperones
• assist the assembly process by inhibiting interactions that would cause incorrect folding
• Nonpolar amino acids
•
• Polar amino acids
•
•
• Acidic amino acids
• aspartate and glutamate
find more resources at oneclass.com
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Document Summary
Bio 330 lecture notes 13: robert hooke. First scientist to observe cork cells (not alive) Called them cells because they reminded him of monk"s rooms in a monastery: antonie van leeuwenhoek. Observed living organisms from pond water (algaea and protozoa); called them animacules. Transmission em: scanning electron microscopy (sem, scans the surface by deflecting electrons, transmission electron microscopy (tem) transmits electrons through a specimen to form an image. Alpha helix (h bonds between every fourth aa- bonds are parallel to the axis) Beta sheet (h bonds between two different regions of the polypeptide- bonds are perpendicular to the axis: tertiary structure. Fibrous and globular proteins: fibrous proteins, strong secondary structure that determines protein shape, globular proteins. Most cellular structure and function proteins are globular. Unique: a-t hydrogen bonds vs g-c hydrogen bonds, at = 2 h, gc = 3 h. Allows for high recognition: stable double helix must be, antiparallel and complimentary.
