viruses , viroids , prions , lichens

Question 1

what are not found in the whittekar classification .?

Answer 1

viroids ,viruses , prions and lichens are not found

Question 2

brief about virus

Answer 2

• non celullar organisms
  -inert crystalline structure outside the living cell
  -once they infect smth they take over the machinary of the cell and replcate themselve often killing the host
  Virus-venom/ poisnous fluid

Question 3

what did dimitri uvanowsky do ?

Answer 3

in 1892, recognised certain microbes as casual organisms of the mosaic disease of tobacco
-which were found to be smaller thsn bscteria

Question 4

M W beijernek 1898 wht he do ?

Answer 4

demonstrated that infected tobacco plant extract caused infections in other plants which are healthy .
-named the pathogen virus
-“contagium vivum fluidum “

Question 5

w.m stanely explain his work

Answer 5

-1935
-figured virusus could be crystallised
virus consists of protins
-inert outside host
-called virus an obligate parasite

Question 6

explain about virus

Answer 6

in addition to protiens the virus also contains genetic material taht is rna and dna
-no virus can conatin both rna and dna
- in the virus neucloprotein is the infectius genetic material

-* viruses that infect the plants - single stranded rna
-viruses whcich infect the animal - single /duble starnded rna or dna
-bacteriophsge /bacerrial virusus usually have single stranded dna

Question 7

structure of virus

Answer 7

protien coats -made of small subunits called capsomers -protects the nucleic acid . capsomers are aranged in helical structure/polyhedral geometric form

Question 8

diseases caused by viruses :

Answer 8

mumps, small pox, herpes , influenza,
AIDS in humans
- virus attack symptoms in plants:mosaic formation , leaf rollingg and curling , yelowing and vein clearing , dwarfing and stundted growth

Question 9

viroids

Answer 9

1971-t o diener -discovered new infectious diseases wich were smaller than viruses -caused potato spindle tuber disease
-no dna
l-lacked protei coat
-rna is of low molecular weight

Question 10

Preions

Answer 10

-cause certain neurological infectious diseases
-agents consisting of abnormally folded protein
-BOVINE SPONGIFORM ENCEPHALOPATHY(BSE)-or aka mad cow disease in cattle and cr jacob disease in humans

Question 11

lichens

Answer 11

symbiotic assosciations btwn alage and fungi
algal component - phycobiont-autotrophic
fungal component- mycobiont-hetertrophic

algae - prepare food
fungi-provide shelter
- good pollution indicatores