Virus,lichens,mycorrhiza Flashcards
Viruses are obligate intracellular parasites, exception to cell theory,active inside cell,link b/w living & non-living entities.
True. Outside cell they are inert & are c/d virion.
Term virus was given by
Pasteur (1880) to denote venom or poisonous fluid.
Who crystallised TMV and told that those crystals consist mainly of proteins.
W.M.Stanley (1935)
What are capsomer?
Capsid is the protein part of virus made up of sub units called capsomers.
Give examples of deoxyviruses specifying ssDNA or dsDNA?
ssDNA = coliphage §x174 ; M13 phage. dsDNA = pox virus, herpes virus, CMV (cauliflower mosaic virus).
Give examples of riboviruses specifying ssRNA or dsRNA?
ssRNA = TMV, HIV, Coronavirus, influenza virus, foot & mouth disease virus. dsRNA = Reovirus, Wound tumour virus.
What is the ratio of nucleotides:capsomers in case of TMV? a)1:3. b)3:1. c)2:3. d) 3:2
6400:2130 = 3:1
Differentiate between T-evenphages, T-oddphages & T5-phage?
Angular head in all 3. Contractile tail : short non-contractile tail : long non-contractile tail. DNA has modified cytosine (5-hydroxy methyl cytosine) : cytosine: cytosine
When only nuclei acid enters the host cell. Such reproduction is called
Phagocytes reproduction…2 types: lytic cycle ( in virulent phages like T4-phage) and lysogenic cycle ( in temperate phages like lambda phage)
When virus enters in the host cell, except its envelope. Such type of reproduction is called
Pinocytic reproduction
Viroids are a)infectious RNA particles. b)obligate parasites. c)smallest self replicating particles. d)all of these.
All of these. #protein coat is absent.
Prions are a) infectious protein particles. b) having misfolded proteins. c) similar to virus in size. d) all of these
All of these. #have misfolded proteins. + do not contain genetic material.
What are virusoids?
RNA viruses but inside the capsid of other larger virus. Do not cause any infection. Discovered by Randle et al.
