III - A. Virology | 1. Classification of viruses. Principles of virus structure. Chemical composition of viruses Flashcards
I. Basics
1. What are viruses?
I. Basics
2. Why are viruses Obligate intracellular parasites?
Can only survive within a host cell and depends on it for replication and metabolic processes
I. Basics
3. What is the size of viruses?
below the resolution of light microscope
=> Size: 20 nm – 400 nm
II. Structure of virus
1. What is virion?
extracellular form of a virus
II. Structure of virus
3A. What are the components of viruses?
II. Structure of virus
3B. What are the Nucleocapsid Essential components?
- Genome – DNA or RNA
- Capsid: proteins protecting genome
II. Structure of virus
3C. What is the genome of virus?
DNA or RNA
II. Structure of virus
3D. What is caspid?
proteins protecting genome
II. Structure of virus
3E. What is the Envelope of virus?
Envelope: lipid bilayer
- contains proteins eg. spikes
- not all viruses have envelope
II. Structure of virus - Genome
4A. How do we classify virus based on genome?
- DNA viruses
- RNA viruses (e.g, Retroviruses)
II. Structure of virus - Genome
4B. Make a schematic diagram of major viral families based on genome structure and virion morphology.
II. Structure of virus - Genome
4C. What are the features of genome of a virus?
- Double stranded (ds) or single stranded (ss)
- Linear or circular
- Segmented NA:
allows easy recombination – lots of variants
II. Structure of virus - Genome
4D. What are the features of retrovirus?
RNA viruses that make a DNA copy of their RNA in the infected cells
=> Reversing the usual direction of NA copy
II. Structure of virus
5. How do virus make protein?
- Viruses need mRNA transcribes from their genome to make the cell synthetize virus proteins
- Type of NA in their genome will direct how they get to this point
- RNA viruses need their own RNA polymerase as host cells don’t have such enyzme
- Viruses will use host cell’s machinery for protein sythesis from these
II. Structure of virus
6. Make a comparison between DNA and RNA viruses?