VIRUSES Flashcards
What are viruses? ()
Are disease causing agents, which lack a metabolism of their own so depends on the metabolism of the cells they infect
What is the structure of a virus? (2)
Have a core nuclei acid around it which is a protein coat called a capsid, some have an additional external envelope of membrane made of lipids and proteins for example the human immunodeficiency virus
Where do antivirals work where they have been developed? ( 1)
Where antivirals have been developed, they musi work by inhabiting viral replication by the chostcells
How do antivirus work where they have not been developed? (1)
’ Where anti virals have not been developed disease control must rely on preventing the spread of the virus.
How do we classify viruses?
Classifying relys on features such as: - the nature and method of copying the nuclei acid cure
- the nature of their capsid
- their shape
- the organisms they infect
What are 4 types of virus? (4)
- ( lambda )bacteriophage
-tobacco mosaic virus
-Ebola virus - human immunodeficiency virus
What host organism does the (lambda) bacteriophage infect? (1)
Usually bacterium escherichia coli
What is the structure of a (lambda) bacteriophage virus? (2)
Has a head, tail and tail fibre.
What is the nature of the nuclei acid core in a (lambda) bacteriophage? (1)
Is double stranded DNA.
What is the copying of the nucleic core in a (lambda) bacteriophage? (1)
Is double stranded DNA transcribed to mRNA.
What host do the tobacco mosaic virus infect? (1)
Plants, especially those in the tobacco family.
What is the structure of a tobacco mosaic virus? (1)
Has a protein coat (capsid) of polypeptide building blocks arranged in a spiral around the canal containing RNA.
What is the nature of the nucleic acid core of a tobacco mosaic virus? (1)
Is a single stranded RNA.
What is the copying of the nucleus acid core in the tobacco mosaic virus? (1)
RNA copied directly to form mRNA.
What host does the Ebola virus infect? (1)
Humans, especially endothelial cells, liver cells, immune cells and dendritic cells.
What is the structure of the Ebola virus? (2)
RNA and outer protein coat.
What is the nature of the nucleuic acid core in a Ebola virus?
Is a single stranded RNA.
What is the copying of the nucleic acid core in an Ebola virus?
RNA copied directly to form mRNA.
What host does the human immunodeficiency virus infect? (1)
Humans, the helper lymphocytes.
What is the structure of the human immunodeficiency virus? (5)
Enzymes, protein coat, capsule, glycoprotein and single stranded RNA.
What is the nature of the nucleic acid core in the human immunodeficiency virus? (1)
Single stranded RNA.
What is copying of the nucleic acid core in the human immunodeficiency virus? (1)
RNA reverse transcribed into a double stranded DNA which is incorporated into the host cells DNA and later transcribed to form mRNA.
What is viral latency? (2)
A period in which under the control of specific latency genes, a pathogenic virus remains dorment. During this time the virus, or its nucleic acid is present inside an infected cell but does not control the cells activities.
What are the two types of viral latency? (2)
-episomal latency
-proviral latency
