What are immunoglobulins? Explain its structure.
Immunoglobulins are popularly known as antibody. These are large Y-shaped
protein produced by B-cells that is used by the immune system to identify and
neutralize foreign objects such as bacteria and viruses. Immunoglobulins are
"Y" shaped structure which is having two tips and each tip of immunoglobulins
contains a paratope. Immunoglobulins are typically made of basic structural
units—each with two large heavy chains and two small light chains. The general
structure of all antibodies is very similar; a small region at the tip of the
protein is extremely variable.
Explain superiority of TLC over paper chromatography.
TLC is superior over paper chromatography because of inorganic nature of
adsorbent concentrated sulfuric acid spray. The spray is then followed by
heating. It may be used to develop on the chromatogram by charring. Also, amino
acid mixtures require 18 hours for separation on paper. It requires 3 hrs using
cellulose TLC. The advantages of TLC lie in adsorbents which don’t allow
separation on paper. In TLC we have much wider choice of adsorbents depending
upon needs and sample.
Explain is isotopic tracer technique?
This technique is used to understand chemical reaction and interactions in
bio-chemistry and chemistry. In this technique, one or more of the atoms of the
molecule of interest is substituted for an atom of the same chemical element,
but that element belongs to different isotope. It can be used to detect the
difference in number of neutrons separately from the other atoms of the same
element. The atom has the same number of protons; it will behave in almost
exactly the same way chemically as other atoms in the compound, and with few
exceptions will not interfere with the reaction under investigation.
Explain the technique of gene conversion.
Gene conversion refers to the event in DNA genetic recombination. This event
occurs at high frequencies during meiotic division but which also occurs in
somatic cells. Through this process we can transfer DNA information from one
DNA helix to another DNA helix, whose sequence is altered. Gene mutation can
also be accomplished through this process. IT may lead to non-Mendelian
inheritance. This phenomenon has often been recorded in fungal crosses.
Differentiate between introns and exons.
An intron refers to any nucleotide sequence within a gene which is removed by
RNA splicing to generate the final mature RNA product of a gene. The term
intron refers to both the DNA sequence within a gene, and the corresponding
sequence in RNA transcripts. Introns are found in the genes of most organisms
and many viruses.
An exon can be referred to a sequence in DNA or its RNA transcript. In broad
sense. An exon is a nucleic acid sequence that is represented in the mature
form of an RNA molecule.