Lesson 10: Viruses and Viral Molecular Biology Flashcards
What type of virus is Covid?
Coronaviridae: Single strand RNA Genome virus
- Circular ssRNA
- does not encode gene products or protein products
- does not have capsid or envelope
- only targets eukaryotic cells
- associated with plant disease
Viroids
Normal variant is alpha helix and mutant is beta-pleated sheets
Prions
Disease is caused by prions
Kuru, Gerstmann-straussler-syndrome, scrapie, bovine spongyform encephalopathy
Virulent phages exhibit the lytic cycle only intemperate features have what you reproductive options?
many of these integrate their genome them into the host becoming a prophage
- lytic cycle
- Lysogenic cycle( May change the phenotype of the host)
Three forms of defense against bacteriophages
- genetic resistance, may alter receptor proteins to prevent binding
- restriction endonucleases, cut an palindromic sequence, viral DNA will be broken down
- crisper integration of phage DNA sequence
Three mechanisms of animal virus entry
- Direct penetration, viruses buying to host cell receptors
- membrane fusion
- endocytosis
DNA viruses replicate in the?
RNA Viruses replicate in the?
Nucleus
Cytoplasm
The induction of defects during embryonic development leading to congenital defects that are present at birth and not genetic
Taratogens Ex:cytomegalovirus (herpes) HSV 1&2 Rubella can leave to deafness in damage to sense organs HIV
Occurs when the sale will reverse back to a more primitive or less definitive state
Anaplasia
The five viruses that account for more than 15% of all the worlds cancer
HBV, HCV, HPV, EPV, and HTLV-I
- largest group of known Viruses
- most bacteriophages
- important vertebrae Viruses (herpes, Poxviruses, Pappovirsies, and adenovirises
Group 1 double-stranded DNA Viruses
Chicken pox virus
HHV-3
Epstein bar virus
HHV-4
Most common congenital infection in US can infect any solve the body, 50 to 80% of adults will be infected by the age 40
HHV-5 cytomegalovirus
Double stranded DNA virus that causes 90% of cervical cancer‘s
Papovavirsus
The only human single-stranded DNA disease
Erythrovirus, B19, fifth disease
Parvoviridase in dogs
- RNA genomes cannot rely on host cell enzymes for GENOME and replication or mRNA synthesis
- RNA dependent RNA polymerase completes lifecycle
- rotavirus and coltivirus
Group 3 double-stranded RNA viruses
Replicates in cytoplasm and synthesizes are in a dependent RNA polymerase
Group 4 (+) sense single-stranded RNA virus
Ex: positive non-enveloped strand RNA virus
- enveloped virons , peolomorphic shape with segmented and nonsegmented genomes
- cannot serve as mRNA to form viral proteins
- must bring into cell preformed RNA dependent RNA polymerase
Group for negative sense single-stranded RNA virus
Ex: orthomyxoviridae-influenza viruses
What are the influenza types?
A-infect humans and animals, associated with the pandemics and epidemics throughout history (pigs and birds are big reservoirs)
B- infects mammals only not as severe and do not have distinguishable stereotypes
C- only mammals, not often infectious disease, distinct from type A And B
Hemagglutinin (HA) 16 types
Neuraminindase (NA) more than 9 types
Acts to attach the virus to the host cells, allows for fusion with host cell membrane
Hemagglutinin
What influenza type undergoes both types of changes?
Type A
Antigenic drift happens all the time
Antigenic shift only happens occasionally
Convert single-stranded RNA into double-stranded RNA using reverse transcriptase then integrates into host cells Genome to serve as a template for mRNA synthesis in genome synthesis
Group 6 retroviruses (reverse transcribing Viruses)
HIV-1 (and enveloped virus with two copies of RNA)
Genetic information transitions through a RNA strand as part of their life cycle
Includes hepatitis B virus (only DNA virus to cause hepatitis)
Group 7 pararetrovirsus
A system that classifies viruses mainly on their means of mRNA synthesis
The Baltimore system
