Immunoglobulin molecules are
produced by the method of inoculation of an immunogen. Immunogen is a molecule
which extracts antibody production by the immune system. Common choice for an
immunogen is a protein molecule. In some cases, glycoprotein, polysaccharide
etc. are also used. Any immune system produces antibody in response to
immunogen. Antigen is a molecule with which an antibody molecule will react.
Hapten is a molecule, small in size, which corresponds to part of the structure
of an antigen which reacts specifically with the corresponding antibody
molecule. Serum is the liquid portion of
the blood that remains after the blood clotting. Immunoglobulin M (IgM) and
Immunoglobulin G (IgG) are present in serum usually in high concentrations. In
the initial stages of immune reaction, IgM is observed. After a while IgG is
observed which is used as a reagent. During the production of IgG, the hapten
is coupled to a protein, thus forming an immunogen. Somatic recombination is a
process employed for the production of the gene for the IgG polypeptide chains.
Polyclonal immunoglobulins are formed
after inoculation in a rabbit.
Tuesday, May 1, 2012
Friday, April 20, 2012
Astronomical instruments
Astronomy is an observational
science which deals with stars, galaxies, clusters of galaxies and other
heavenly objects. An astronomical instrument plays a major role in developing
science in astronomy. Most commonly and extensively used instrument in
astronomy is telescope. Three main varieties of telescope are optical
telescope, radio telescope and Hubble space telescope. Telescopes which are
used for observations in the optical wavelengths of the electromagnetic
spectrum are known as optical telescopes. Here two types are there- refracting
and reflecting. Refraction telescopes which are smaller in size are widely
used. The important terms used in optical telescopes are magnifying power,
image brightness, resolving power and focal ratio. Telescopes which are used
for the detection of electromagnetic radiation emitted in the radio wavelengths
are known as radio telescopes. Hubble space telescope is an orbiting telescope.
Astronomical spectrograph is a widely used instrument which can separate a
non-monochromatic light beam into its constituent wavelength followed by the
recording of the intensities of the radiation according to the wavelengths.
Here observations are made with naked eye with an eyepiece. The main part of a
spectrograph is a dispersive medium which is either a prism made of
glass/quartz or a diffraction grating. Modern photoelectric methods are
employed in photoelectric photometry. The main parts of an astronomical
photoelectric photometer are an eyepiece, a focal plane diaphragm, a field
lens, filters and a detector with amplifier and a recording system. Stellar
spectrophotometry, photographic spectrophotometry and photoelectric
spectrophotometry are some other methods used in astronomy.
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