Viruses Flashcards
Are viruses true cells?
No
What is the structure of viruses?
They consist of a nucleus acid core(RNA or DNA) and are surrounded by a protein coat
What is the function of viruses?
They are organisms that cause disease
Define pathogenic
Organisms that cause disease
Can viruses reproduce on their own?
No
State some examples of diseases that viruses can cause
AIDS and Haemorrhagic fevers in humans
Foot and mouth disease in cattle
Rabies in dogs
Leaf-curl in plants
Why are viruses considered to be quasi-living?
They cannot function outside the body of a host living organism
What suggests that have some things in common with living cells?
They contain the same nucleic acids found in the nuclei of living cells
What are viruses also considered to be?
Pathogenic
How are viruses spread?
By air, fluid, or transported from one host to the next by a vector
Define a vector
An organism that carries a disease without itself being affected by it
What other groups can be invaded by viruses?
Bacteria
Fungi
Protista
Insects
How does a virus infect a host cell?
The virus looks for a cell receptor it can fit into and attaches itself to it
The virus then enters the body by endocytosis
The host cell then removes the viruses protein coat and releases the viral nucleic acid into the cytoplasm
Once the host cell is infected, the viral RNA is then synthesised into DNA by the reverse transcriptase
The viral DNA is then incorporated into the host cells DNA
The viral DNA has now taken control over the host cells DNA, amino acids and ribosomes to make replicas of its own RNA and protein coats, the viral DNA then assembled the RNA and proteins coats together
The new virus then escaped the host cell by bursting out of the cell killing it in the process or by budding where the virus is contained in a vesicle
What type of plants do viruses attack?
Plants with plants cells that have damaged cell walls
How can plant cell walls be damaged?
Pruning
Wind blown sand
Chewing and sucking insects
