viruses

• what is a virus


  DNA or RNA wrapped in a protein coat called a capsid- they areacellularandnon-living
• structure of viruses


  - Containgenetical material(DNA/RNA)-Capsid- Attachment proteins
• HIV virus


  -Retrovirus- as it contains RNA not DNA- Containsreverse transcriptase
• what is reverse transcriptase


  An enzyme which allows the virus to form a double helix of DNA from its single stranded RNA when it infects a host
• what cells do HIV viruses attack


  - Usually infects and destroysT helper cells- As the number falls the body is unable to produce effected immune response against pathogens- Because T helper cells can't activateB cells- B cells are responsible for antibody production
• how does the HIV replicate inside T helper cells


  1. Attachment proteinsbindHIV to host's receptors2.Protein capsidis inserted into host cellRNA is released3.Reverse transcriptase enzymesconvertviral RNAinto a complementary strand of DNA4. Viral DNAbindswith human DNA5.Host enzymesmakeviral proteinsfrom viral DNA which then turn into new viruses6. Eventually the cellsburstsand can no longer complete its job
• Why are drugs/antibiotics ineffective against viruses


  - Antibiotics kill bacteria enzymes and ribosomes- These are different from humans- Viruses use human enzymes and ribosomes so antibiotics can't stop them- Viruses also hide within other cells so arehard to target