O'Leary Lecture 1 Flashcards
What can we use to measure atoms, ribosomes, viruses, anything from 0.1 nm to 100 nm?
x-ray diffraction
What measures molecules from 0.1 nm to 10 nm?
NMR
What wavelength can an electron microscope measure?
0.1 nm to 100 µm
What can a light microscope measure?
100 nm to 1 mm
How small can the human eye see?
a little less than 1 mm
How does biology techniques vary with time?
Functions operate across a wide range of time scales, from bond vibration (10^-14 s) to movement of molecules around the cell (1 s)
- enzyme turnover rates
- cell doubling
- animal lifespan
What are the building blocks of protein and ribosomes?
Protein: amino acids
Ribosome: Nucleotide
What are macromolecules?
Polymers, smaller molecules/building blocks combined into a large compound
How do we measure structure-function relationships?
Ex. enzyme activity, receptor/ligand binding, intracellular localization
Need a physical property that acts as a reporter for the structure or function of interest
- equilibrium/stability: thermodynamics
- approaching equilibrium: kinetics
What is spectroscopy?
Study of interaction of matter with electromagnetic radiation
What are the restrictions of spectroscopy?
- sensitivity
- selectivity
- time resolution
- non-destructive
- broad range of complementary measurement methods
How does electromagnetic radiation work?
- Oscillating electric field
- Orthogonal oscillating magnetic field
- waves that oscillates at right angled to its direction of propagation (transverse)
- directional
- characterized by wavelength
What is the energy equation characterized by wavelength?
E = hc/λ
h = planck’s constant = 6.62610^-34 Js
c = speed of light = 3.010^8 m/s
energy is inversely proportional to wavelength
How is wavelength related to momentum?
λ = h/p
h = planck’s constant = 6.626*10^-34 Js
p = momentum
What is the relationship between light and energy?
E = hv
h = planck’s constant = 6.626*10^-34 Js
v = frequency
energy difference between the initial and charge-redistributed states and the energy of the radiation must be equal.
How are atoms distributed?
Nucleus = heavy, positively charged
Electrons = light, negatively charged
How are electrons distributed between atoms?
Covalent bonds
- equilibrium positions of the particles represents a balance of attractive and repulsive forces between negatively charged electrons and positive nuclei
What happens if the electron cloud is distributed asymmetrically?
Molecule is considered polar and has a dipole. The dipole moment is a vector with a direction determined by the shape of the molecule.
What happens when light is introduced?
When the perturbation results in an allowed quantum mechanical state of the molecule, energy from the EM radiation will be absorbed.
