Viral Genomics Flashcards
Define viruses
Minuscule, acellular, infectious agents, either DNA or RNA
Do viruses have the ability to carry out metabolic pathways?
No
Do viruses grow or respond to the environment?
No
Can viruses reproduce independently?
No
What is a virus called in its extra cellular state and what are its components?
Virion
Protein coat
Nucleic acid and capsid (nucleocapsid)
Some have phospholipid envelope
Outermost region provides protection and recognition sites for host cells
What is the intracellular state of a virus?
No capsid (removed)
Virus exists as nucleic acid
What is a bacteriophage?
A virus that can infect and genetically takeover bacteria
Do viruses have cells?
Nope!
What do viral genomes consist of?
Double/single strands of DNA
Double/single strands RNA
Linear or circular molecule of nucleic acid and contains several thousand genes
Describe a capsid
A protein shell that encloses the viral genome
Built from protein subunits called capsomeres
Capsids can have various structures
What are the common various shapes/structures of capsids?
Helical
Icosahedral
Complex
What are the two reproductive mechanisms of a bacteriophage?
Lytic cycle
Lysogenic cycle
What are the 5 stages of the lytic cycle?
Attachment
Entry (of phage DNA and degradation of host dna)
Synthesis (of viral genomes and proteins)
Self assembly (of the synthesized genomes and proteins-head, tail, tail fibers)
Release!
What defence mechanisms do bacteria have against phases?
Restriction enzymes that cut up phage dna
CRISPR - Cas system
Animal infecting viruses are classified by what two key variables?
If they are made from DNA or RNA
If they are single stranded or double stranded
What makes a retrovirus distinct from other viruses?
Use reverse transcriptase to copy their RNA genome into DNA (HIV)
