KEY POINTS
v Over one and a half million species of animals and over a half million species of plants are known.
v All organisms are related to one another at some points in their evolutionary history.
v Species are independent evolutionary units.
v Members of a lower category resemble one another more than do the members of higher taxon.
v Dozen of plants with bell shaped flowers are called blue bells.
v ‘Cray fish’, ‘Jelly fish’ and ‘Starfish’ do not fit the biologist’s definition of a fish.
v Different classification systems organize two to six kingdoms.
v Kingdom Protista was proposed by E.Hackel.
v E.Chatton suggested differentiating terms procariotique used to describe bacteria and blud-green algae and the term eu-caritique to describe animal and plant cells.
v Procariotique is a Greek word meaning “before nucleus” and Eu-caritique is also a Greek word meaning true nucleus.
v A relatively recent system of classification, the five kingdom system was proposed by Robert Whittekar (1969).
v Helizoans are animals that move towards light. It is an alternate name of Euglenoids.
v A Phylum or sub-kingdom of monerans that includes methane producers sulphur dependent species, and cells that tolerate very salty or hot environment, and is thought to be very ancient is Archaebacteria.
v Sac fungi are also called Ascomycetes.
v Club fungi are also called Basidiomycetes.
v The branch of biology which deals with the study of virus is called virology.
v Non-cellular infectious entities which contain either RNA or DNA, normally encored in protein aceous coat and reproduce only in living cells are called viruses.
v They range in size from 250nm of poxviruses to 20nm of parvoviruses.
v Viruses are obligate intracellular parasites.
v The complete, mature and infections particle is known as virion.
v Nucleic acid is surrounded by a protein coat, the capsid is made up of protein subunits known as capsomeres.
v 162 capsomeres are present in the capsid of Herpes virus and 252 in the capsid of Adenovirus which cause some common cold.
v Nucleic acid and capsid are collectively known as nucleocapsid.
v Non- enveloped viruses are know as naked virions.
v Prions are responsible for mad cow infection and mysterious brain infection in man.
v The volume of phage is about 1 / 1000 of host.
v The major cells infected by HIV is the helper T-lymphocytes. Which is major component of immune system.
v Recent studies of HIV reveals that the virus infect and multiply in monkey but do not cause disease in them, which meant that HIV is, host specific.
v Hepatitis is an inflammation of liver.
v HAV is an RNA virus but it is non-enveloped. HCV is also an RNA virus but it is enveloped.
v HBV is a DNA virus. Pig could be the source of infection of Hepatitis E.
v Genetically engineered vaccine is available for HBV. Vaccine is also available for HAV but not for HCV.
0 comments