VIRUSES Flashcards
why does virus is not included in the 5 kingdoms?
because it simply consist of nucleic acids surrounded by coat protein and only survive inside living organisms
virus cannot independently perform metabolic activities. why?
they do not have the components necessary to carry on cellular respiration or to synthesize proteins and other molecules
what is bacteriophages?
viruses that infect bacteria
what is the different between T3, T7 phages and T-even phages?
T3, T7 - icosahedral head, short tails.
T-even - icosahedral head, a capsid that consists primarily
of three proteins, a connecting neck with a collar and long whiskers, a long tail, a complex base plate
virus is the smallest living organism. state the types of virus
poliovirus-typical small virus
poxvirus- large virus causes smallpox
TRUE OR FALSE
- all virus have the same basic structure.
- all viruses form a capsid around their nucleic and core.
- some viruses store specialized enzyme within the capsid
- viral capsids are generally either helical or polyhedral or a complex combination of both.
- TRUE
- FALSE (NEARLY ALL)
- TRUE
- TRUE
envelope form around the capsids of animal viruses is rich in?
rich in proteins, lipids, and glycoprotein molecules.
Individual viruses contain only a single type of nucleic acid, either DNA or RNA. is this statement true?
yes it is true.
notes: RNA-based virus known as retrovirus
viruses reproduce only within the complex environment of the living cells they infect, explain.
viruses use their genetic information to force the host cell to replicate the viral nucleic acid and to take over the translational and transcriptional mechanisms of the host cell. the host then synthesizes the capsid and envelope components of the virus.
- Whole virus or genetic material enters host.
- Virus attaches to host cell.
- Viral nucleic acids and proteins are assembled.
- Viral DNA or RNA directs host to make viral genetic
material and protein. - New viral particles are released from cell.
rearrange the steps for viral multiplication above.
2 , 1 , 4 , 3 , 5
life cycle is the same in principle for all phages. describe lytic life cycle.
phages ATTACH its tail to a special receptor on the surface of a bacteria. then it PENETRATEs by injecting its DNA into the bacteria cell through the plasma membrane. next, the virus DNA will destroy the bacterial DNA and takes over the bacteria cell for REPLICATION to produced ,ore copies of the virus. the viral component are CONSTRUCTED together t form a complete virus. lastly lysis occurs as lysozyme is secreted to RELEASE the virus.
in lysogenic life cycle the virus does not kill its host outright instead it integrates its viral genes into the host. what happen in the process?
Attachment – the phage attaches to the cell surface of bacterium
Penetration – phage DNA enters the bacterial cell.
Integration – phage DNA integrates into bacterial DNA.
Replication – the integrated prophage replicates when bacterial DNA
replicates
viruses are agents to many diseases. can it also infect eukaryotic cells as in prokaryotic cells?
yes it can
examples of DNA viruses
Poxviruses – smallpox, cowpox
Herpesviruses – genital herpes, chickenpox
Adenoviruses – respiratory tract disorders –
tonsillitis
Papoviruses – degenerative brain diseases, some
cancers
Parvoviruses – infections in dogs
examples of RNA viruses
Picornaviruses – polio, hepatitis A, aseptic meningitis
(coxsackievirus)
Togaviruses – rubella (german measles)
Orthomyxoviruses – influenza
Rhabdoviruses – rabies
Coronaviruses – upper respiratory infections, SARS
Flaviviruses – yellow fever
Retroviruses – AIDS, some types of cancer
