2017
GIVE ONE EXAMPLE OF A BENEFICIAL VIRUS
Bacteriophages can be used to control bacterial infections
DESCRIBE HOW THE VIRUS REPLICATES
- Virus attaches to a host cell and inserts its nucleic acid into the cell cytoplasm.
- The viral enzyme destroys the host cell’s nucleus
- The virus uses host cell’s machinery to make more viral dna and protein coats
- New viruses are assembled and burst out of the host to infect other cells
DISCUSS THE STATEMENT “VIRUSES ARE NOT CONSIDERED TO BE LIVING”
Viruses have some features of living things, e.g. containing RNA or DNA, being able to replicate and having a protein coat. However, other characteristics of living things are missing, e.g. viruses are non-cellular and cannot reproduce on their own. Viruses do not have cell organelle and only contain one kind of nucleic acid while most living things have both RNA and DNA.
VIRUSES ARE OBLIGATE PARASITES
They cannot exist without a living host
NAME ONE VIRUS THAT CAUSES DISEASE AMONGST PLANTS
Tobacco mosaic disease
HOW DO SCIENTISTS DISTINGUISH BETWEEN DIFFERENT VIRUSES
According to their shape, round, rod or complex
WHY ARE VIRUSES DIFFICULT TO CLASSIFY INTO A KINGDOM?
Because they are not made up of cells and are unable to carry out metabolic reactions on their own.