Whittaker's Five Kingdom Classification | Biology Blog

                                   Five Kingdom Classification

Early biologists classified all species as either plants or animals. Since this method makes it difficult to research specific creatures, American taxonomist R.H. Whittaker created the five-kingdom classification in 1969. This system divides all organisms into groups based on how they are organized and how they are fed. Important standards for this classification include -

• The complexity of cell structure i.e. Prokaryotic and Eukaryotic.
• The complexity of the Organisms body is Unicellular and Multicellular.
• Mode of nutrition Autotrophs and Heterotrophs.
• Lifestyle.
• Phylogenetic Relationship.

Based on these criteria, Whittaker classified the living world into the following categories  -

• Kingdom Monera                
• Kingdom Protista
• Kingdom Fungi
• Kingdom Animalia
• Kingdom Plantae 

Kingdom Monera -

• Kingdom monera includes Prokaryotic Organisms.
  
  
•   Their nutritional methods are different like they are autotrophs, heterotrophs, or chemoheterotrophs.
  
  
•  They do not have a nuclear envelope.  
  
  
• They do not have cell organelles like mitochondria, lysosomes, Golgi body, endo plastic reticulum, etc.
  
  
• With the help of asexual reproduction, they continue their species' existence.
  
  
• Flagella is present for its locomotion.

Kingdom Protista-                

• Protista includes eukaryotic organisms that neither can be divided into fungus, animals, or plants. 
  
  
•    Nuclear envelope present. 
  
  
•     Autotrophic in nutrition.
  
  
• Mostly they are unicellular organisms but some are multicellular like kelp which provides shelter, oxygen, and nutrient to the underwater ecosystem. 

Kingdom Fungi -  
                                     

• Fungi include eukaryotic organisms.
  
  
•      Presence of nuclear envelope.
  
  
•      Heterotrophic in nutrition.
  
  
• The cell wall is made up of cellulose and chitin. 
  
  
• They reproduce by both means asexual and sexual.

For more information also read - Kingdom Fungi  in detail


Kingdom Animalia -

• They are multicellular organisms that do not possess chlorophyll in their body.
  
  
•         Nuclear envelope present.
  
  
•         Heterotrophic in nutrition.
  
  
• They are eukaryotic organisms. 
  
  
• They reproduce through sexual reproduction. Asexual reproduction is present in some lower forms of animals.
  
  
• Muscle cells are present in the body which do contract and relaxation in their body parts. 

Kingdom Plantae -

•   They include Eukaryotic organisms.
  
  
• They contain photosynthetic pigments in plastids. 
  
  
• They are primarily non-motile and attached to the solid substrate for getting support.
  
  
•     Nuclear envelope present. 
  
  
•    They are autotrophic in nutrition.   
  
  
• The mode of reproduction is asexual and sexual.

 

Advantage Of Five Kingdom Classification-  

• Prokaryotes differ from all other organisms in their cellular structure, physiology, biochemical, and reproduction processes. They have got a separate place as kingdom Monera in five kingdom classification.
  
  
• All the unicellular and multicellular organisms are kept separate.
  
  
• Similarly, autotrophs and heterotrophs are kept separate.

Disadvantages Of Five Kingdom Classification - There are so many advantages of classification although there are some shortcomings also -

• There is no place for the virus in any five kingdoms.
  
  
• Similar organisms whether they are unicellular or multicellular are kept apart like unicellular and multicellular algae. 
  
  
• All organisms other than the monera show that they are polyphyletic in origin. 

   

Related Link - Need for classification of the living being

Recombinant DNA Technology | Biology Blog

                                 Recombinant DNA Technology

The technology in which genetic material   is transferred by artificially means from one organisms to genome of another organisms where it replicate and expressed is  called Recombinant  DNA Technology .
For Example - The best example to understand this process is Mosquito . Mosquito act as a vector and transfer it's pathogen into human body where it replicate and expressed in form of disease called Fever , Dengue , Malaria etc .


Tools Of   rDNA Technology - rDNA technology accomplish only  by  using this key tools -
                                               

•        Restriction Enzyme
  
  
•        Polymerase Enzyme
                                                      
•        Ligase Enzyme
  
  
•        Vector
  
  
•        Host Organisms

Restriction Enzyme -  As the name suggest the enzyme which restrict the entry of foreign DNA into the bacteria is called Restriction Enzyme .The enzyme was first postulated by W. Arber . This enzyme  cut  the DNA at specific sites called as restriction sites .Some restriction enzyme recognize the sequence and make palindromic sequence while some enzyme cut staggered cuts and sticky cuts . They are classified into four types , Type 1 , type 2 , type 3 , type 4 based on their composition . From the bacterium Haemophillus  Influenza the first enzyme  was isolated  named as HIND 2 . After discovery of Hind 2 , another Eco R1 was discovered .

How This enzymes  were named -  For the nomenclature of the enzyme scientist give out some rules -

The first letter of the enzyme is taken out from Genus.
The second two letter is from species .
The third letter is taken out from strain
The fourth is number on which sequence it is identified .

For Example - EcoR1 here , The first letter is from Genus and second two letter is from species . 'R' represents strain  and the number here is showing the sequence on which it is identified .

Polymerase Enzyme -  This enzyme play a important role in DNA technology. The basic function of this enzyme is to make more than one copies of  DNA . After inserting the desired DNA into the  host organisms it start replication which is due to  the help of this enzyme .

Ligase  -  This enzyme is also known by its another name Molecular Glue .  Ligase enzyme joined the two strands of DNA  covalantly by catalizing the formation of  phosphodiester bond between a 5' phosphate and 3' hydroxyl .

Vector -  The word Vector is generally refer to the transporter which carry some things to transfer into the desired place . Similarly the Vector carry foreign DNA and transport  into the suitable host . There are so many types of Vector are there like Plasmid , Cosmid , Lambda Phase  etc .

For transferring foreign DNA into the host cell the Vector have some specific features  like -

• They should  contain origin of replication .
  
•  They  are small in size .
  
• Must able to replicate in host cell .
   
• should have multiple cloning sites .

Also Read - Watson & Crick Model Of DNA

Process Of DNA Technology -

• To make recombinant DNA the foreign DNA is inserted into the Cloning vector .
  
• Enzyme Ligase seals the two DNA fragments and in this way DNA of different origin are joined together which is called as recombinant DNA.
  
• This cloning vector is taken by host cell where the process of amplification takes place .
  
• Now this transformed cells are plate out in a solid nutrient medium containing ampicillin medium and X- gal .
  
• Only the transformed cell will grow now having ampicillin resistance property .

Also read - DNA Transcription Process | Central Dogma | RNA Polymerase

Importance Of rDNA Technology  -  rDNA technology is the most important technology in today's century as this is responsible for curing from all  genetic diseases . Except this there are some area where rDNA technology has its won impact -

• Better Crops.
  
• Production Of Insulin.
  
• Recombinant Vaccines .
  
• Germ line therapy.
  
• Production of recombinant pharmaceutical .