Viruses Flashcards
Virome
Types of viruses you have in you, affected by breast feeding, genetics, travel, where you live, who you live with etc
Virus size
20-230nm, 100 to 1000 times smaller than human cells
5 Virus characteristics
- Intracellular parasites
- A cellular, lack cellular structure, no organelles, no cytoplasm, no nucleus
- Cannot replicate or metabolism
- Interact with specific cell receptors
- Tissue/host tropism
What do viruses lack?
ATP generation, lack enzymes for protein synthesis, can only reproduce using cellular machinery of other organism
Explain the virus host range
range refers to what organisms (hosts) that a virus can infect and it is basedon a virus’s capsid structure. Viruses have a very narrow host range
Define tropism
Affinity of viruses to certain tissues or cells
HIV host range and tropism
Host range (human)
Tropism (macrophages and T helper cells)
Rabies host range and tropism
Host range (human/warm blooded animals)
Tropism (nervous system)
What are viruses made of?
Nucleocapsid
Capsid (capsomer)
Nucleic acid
Nucleocapsid
The combination of capsid + nucleic acid
What is the capsid and what is it made of?
Protein coat around the nucleic acid made up of capsomers
Nucleic Acid
– Contains the viral genome- only one type of nucleic acid - DNA or RNA nucleic acid of a virus can be single ordouble stranded
– the nucleic acid can be linear or circular
DNA vs RNA virus
(genome size, replication rate, mutations)
DNA has:
- Large genome, less dependent on host
- Slower replication due to size
- Lower mutation due to decreased transcription error (double strand = more stability)
RNA has:
- Small genome and highly dependent on host
- Rapid replication due to small size
- High mutation due to high errors in transcription
Explain the viral envelope and it’s 3 components
Derived from the host cell membranes, made up of either lipid or glycoprotein, consists of three main proteins (enveloped protein, spike protein, membrane)
Examples of enveloped viruses
COVID, influenza, HIV and RSV