Lichens,Prions, Viroids ,Viruses

Lichens 

 

ALGAE  + FUNGI

ALGAE : -
Phycobiont
chloroplast chlorophyll
synthesis their own food =  autotrophs
prepare / provide food for fungi .

 FUNGI :-

mycobiont 

Heterotrops

absorptive mode 

provide shelter & absorption of water & minerals from soil .

algae + fungi → ( symbiosis relationship )

* mutualism

* pollination indicator - lichens do not grow in polluted area    

Prions

                                        

Size = similar to viruses .

infectious proteinaceous agent 

 Proteinaceous  = protein only 

Acellular / non-cellular 

pathogenic → nerogenic disease causing  (Cattle & Human ) 

 nerogenic disease causing :-

Cattels → mad cow disease or BSE =  Bovine spongiform encephalopthy 

 Human Cr JD ( J = jacob ,D =  disease )

 Viroids

 Viroids

                               

1971 = T.O. Diener
 Acellular / non-cellular 

infection free RNA 

infection = pathogenic disease causing  → potato spindle tuber  disease 

RNA = Low molecular wt. ,nucleic acid  

Viruses

Viruses 

                              

                                

Viruses = means = venom ( poisonous fluid ) = pasteur .
Acellular / non-cellular 

Recognizes causal organism of mosaic  disease in tobacco

    ↳ D.J. Ivanowsky ( 1892 ) 

Viruses pass from bacteria proof filter i.e. viruses to be smaller then bacteria 

Contagium vivum fluidum → M.W.Beijerinek (1898 )

↳ ( infectious poisonous fluid )

W.M.Stanley ( 1935 ) = crystallization = nucleoprotein  

nucleo = nucleic acid (DNA or RNA ) both never present in viruses 
protein = Capsomere sub unit
Capsomere = Caspid / protein coat
pathogenic → disease causing → plant & Animals
plant disease = (Plants Viruses SS RNA )

• Yellowing & vein clearing 
• dwarfing & stunted growth 
• mosaic formation

 Animals disease ⇒   (Animals Viruses SS RNA & ds  RAN ,ds DNA) 

• Common cold 
• AIDS 
• SMALL POX 
• MUMPS 
• HERPS 
• INFLUENZAE

INFLUENZAE

↪ Viruses that infect bacteria = Bacteriophage ds DNA
Viruses :↴
Mutation 
submicroscopic 
Host specific 
Acellular / non-cellular  organism
Inert crystalline structure outside living cell 
Connecting link b/w living & non living cell 
Hijack or overtake metabolism to it 
Intracellular  obligate parasite

Structure of Virus

                                

Size order ⇒ Bacteria > virus = prions > viroids