- Hirudin is a protein that prevents blood clotting. The gene
encoding hirudin is chemically synthesized. This is then transferred
to Brassica napus, where hirudin is accumulated in seeds. It is then
purified and used as medicine.
- A soil bacterium Bacillus thuringenesis, produces a
crystal “cry” protein. This protein is toxic to the larvae of certain
insects. There are various types of cry protein each resistant to
specific type of insect.
- Viral chromosomes consist of proteins and one nucleic
acid i.e. DNA or RNA. Nucleic acid may be single or double
stranded, may be circular or linear. Virus with RNA as genetic
material is called as retrovirus e.g. HIV [Human Immuno
Deficiency Virus]
- Replication : DNA is the only molecule capable of self
duplication so it is termed as “living molecule”. All living beings
have the capacity to reproduce because of this chrematistic of DNA.
DNA replicates in the “S” phase of cell cycle. In the process of
replication a new DNA is synthesized in the form of strands.
- These strands are of two types :
(i) Leading strands : Formation of new strands always takes
place in 5’ - 3’ direction. It is a continuous strand.
(ii)Lagging strand : it is formed as small fragments known
as okazaki fragments. These fragments are later on joined by
ligase enzymes.
DAILY PRACTIVE PROBLEMS # 14
