Virus Practice Questions

Practice W I. Virus : A virus is a infectious agent Viruses are not composed of capable of cells ,...

Practice W I. Virus : A virus is a infectious agent Viruses are not composed of capable of cells , they are not autonomous reproduction they , lack enzymes and ribosomes for production of their own proteins They do not react to outer Stimuli, netheir preform active movement They. have their own genetic information encoding for viral proteins , but they can only replicate inside host cells. They are fully dependent on host cell enzymes , ribosomes , resources of energy and chemicals. which they use to form their own components They are not visible under light microscopes they are visible under electron microscopy more precisely TEM. The structure of a virus : A viron is a complete Virus particle , it contains nuclear acidtheir DNA or RNA , a capsid (protein Protective Coaf) Some of them also contain Viral envelope which is formed of modified cell membrane of the host cell , phospholipids and proteins + glycoproteinss. · Nucleoproteins - proteins associated with nucleic acid. Nucleocapsid-assembly of viral capsid proteins and viral nucleic acid · * A viron is outside the host cell Since its a complete virus. The virion is the form in which a virus spreads from one host to another & Good to know - > SNA virus : Chickenpox , small pox herpes , #1 - Parrovirus RNA Virus :RNA : diarrhoea +1 > comon cold Covid 19 - , - = > - influenza Viruses dependent on reverse transcription # in Cretrovirus) + hepatit B & Virus infects Eukaryotic cell Bacteriophage (Phage) infects prokaryotic · cannot infect humans · use in research or as antibacterial treatment  Retroviruses: is envelopedSSRNA viruses and are dependent on the reverse transcriptase - > Which means the enzyme transcribes their genomic RNA into DNA which then integrates using a integrate enzyme into the host cells genome as a provirus, In the form of provirus , the virus can persist for Several years (latent phase) does not form new virions and does not cause symptoms , until later virus entry into the host cell Proteins and glycoproteins on the surface of the virus bind to specific receptors on the host cells surface. Every virus infect only type of host cells cell without the respective receptor infected the virus. can certain , cannot be by Prevention of Viral diseases : Prevention - > development of immunity before a potential infection Vaccination Cactive immunization) the goal is to produce memory Lymphocytes which in B case of a infection it taks a quick and effective immune response. * vaccine can contain viral particles weakened by cultivation (controlled environment) - - Viral DNA or MRNA-cells themselves produce an antigen that gets exposed on their surface - inactivated Viral particles (rabies - Viral Proteins  Treatment of viral diseases Treatment - after the infection burst Antivirotics-starget and inhibit the growth or replication of viruses How to find out that something is infected with a ? virus - Laboratory detection Viral Culture - > Growingthe virus in cells > takes time -. Antibody test - > Proteins made by the immune system to fight infections) in the blood · Viral nucleic acid > look - for genetic code eg. DNAOrRNA in a sample from a infected person eg. blood - Precise (PCr) · Antigen Test (finding Virus proteins in tissue or blood) special fluorescent added proteins , if microscope A antibodies are to a sample to attach to virus particles or they are present , the antibodies will glow under a. Confirming an infection - Fast and useful inefections. for diagnosing active Bacteriophages (phages) · Viruses infecting and lysing (killing) bacteria Promising alternative to antibiotics. Life cycle of bacteriophages : · Lytic cycle -> host cell lysis (breakage Lysogenic Cycle integration into host cell in the form of prophage > genome - · · virulent phage-undergoes lytic cycle only Temperate · Phage-has the ability integrate into the bacterial cell genome  prions · infectus proteins cause fatal neurodegenerative diseases by misfolding and spreading within the brain. Prions has no DNA or RNA they are misfolded proteins that can cause normal proteins in the brain to misfold Practice W. 2 Characteristics of Prokaryotes What do bacteria and eukaryotic have in common ? · Basic units are cells · They show autonomous metabolism and reproduction (cell division) They are capable of active movements They respond. to outer stimuli What do they differ in ? - Presence of cell wall - lack of membrane Organelles Prokaryotics Unlike Viruses has their own enzymes and ribosomes ProkaryoticStructure - unicellular - No nucleus - Nucleoid (1 circular DNA molecule) - Cytoplasm - cell membrane - cell wall