Viruses Flashcards
Explain how a plant might show symptoms of viral infection.
Local lesions (chlorotic or necrotic), chlorosis, necrosis, mosaics or morphogenetic disturbances (changes in form/structure).
Describe the structure of TMV.
Helical capsid, rod-shaped particles always 18 by 300nm in size containing single stranded RNA.
How many proteins does TMV replication produce?
Four
Explain the roles of TMV’s proteins.
Two types of replicase proteins which are used to translate the movement and coat proteins.
List some common plant disease vectors/modes of viral transmission.
Aphids, nematodes, fungal spores, mechanical or sexual transmission.
How do influenza particles attach to host cells?
Use the envelope protein haemagglutinin to attach to specific surface carbohydrates on the epithelial cells.
How does influenza release itself from the host cell?
Using a protein called neuraminidase.
What is genetic drift of viruses; use influenza as an example.
mutations (to haemagglutinin and neuraminidase in flu virus) during viral replication (common in influenza because RNA polymerase doesn’t proofread) allows viral resistance to vaccines.
Give three methods of viral prevention in plants.
insecticides, plant breeding to produce virus-resistant varieties, cross protection (inoculation w/ mild strain of virus), coat-protein mediated resistance, GM to produce EBF synthesizing plants (repel aphids which are viral vectors).
