Lecture 9/8/14

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Lecture 9/8/14
2014-12-06 12:19:21
BME 221

BME 221
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  1. Molecular self-assembly
    It is dicult to manufacture anything on the nanometer scale (i.e. < 100 nm). As an example, we cannot use photolithography to manufacture computer chips, as visible light has a spectrum of 300- 700 nanometers. Structures under half of the wavelength used in such processes can only be made by using special tricks. Industry now turns to UV light to achieve a nanometer scale lithography (now 22nm for Intel Haswell). The nature solves the problem by using molecular self-assembly of molecular and macromolecular building blocks.
  2. Characteristics of life
    • Self-replication
    • Growth
    • Response to stimuli
    • Compartmentalizied (cells)
    • Maintains homeostasis
    • Metabolism
    • (Mortality)
  3. Biological membrane
    • Biological membranes are thin (3-5 mm), lipid bilayers. They are electrical insulating and provide a barrier to flux of ions. In cells, energy is stored by concentration gradients. Lipids and fats (triglycerides) store a lot of energy since they contain a lot of carbon in a reduced form.
    • Inspired by biological membranes, lipid vesicles are sometimes used for drug delivery.
  4. What is an orbital?
    An atomic orbital describes the probability distribution of the location of electrons.
  5. What is a Van der Wall bond?
    • Van der Waals interactions are attractive forces due to transient dipoles that induce transient dipoles in neighboring atoms or molecules. These attractive forces have very short range.
    • Van der Waals forces are induced by transient dipoles within atoms or molecules themselves, or due to other molecules. They are generally non-directional.
  6. What is a hydrogen bond?
    A hydrogen bond is the electromagnetic attractive interaction between polar molecules, in which hydrogen (H) is bound to a highly electronegative atom, such as nitrogen (N), oxygen (O) or fluorine (F).