T O Diener discovered a
free infectious RNA
free infectious DNA,
infectious protein
infectious protein
A.
free infectious RNA
Viroids are small, circular, single-stranded RNA molecules that are the smallest known pathogens.The extracellular form of the viroid is naked RNA, ie, there is no protein capsid of any kind. Even, the RNA molecule contains no protein encoding genes and therefore, the viroid is totally dependent on host function for its replication. No viroid diseases of animals are known and the precise mechanisms by which viroids cause plant diseases remain unclear.
Which one of the following has haplontic life cycle?
Funaria
Polytrichum
fully developed foetus and placenta
fully developed foetus and placenta
Peripatus is a connecting link between
Ctenophora and Platyhelminthes
Mollusca and Echinodermata
Annelida and Arthropoda
Annelida and Arthropoda
Select the correct combination of the statement (A-D) regarding the characteristics of certain organisms.
A. Methanogens are Archaebacteria, which produce methane in marshy areas.
B. Nostoc is a filamentous blue-green algae, which fixes atmospheric nitrogen.
C. Chemosynthetic autotrophic bacteria synthesise cellulose from glucose.
D. Mycoplasma lacks a cell wall and can survive without oxygen.
B, C
A, B,C
B, C, D
B, C, D
Trichoderma harzianum has proved a useful microorganism for
bioremediation of contaminated soils
reclamation of wastelands
gene transfer in higher plants
gene transfer in higher plants
Which one of the following is wrongly matched?
Puccinia - Smut
Root - Exarch protoxylem
Cassia - Imbricate aestivation
Cassia - Imbricate aestivation
Phylogenetic system of classification is based on
evolutionary relationships
morphological features
chemical constituents
chemical constituents
