3.2.4- Cell Recognition- HIV & Viruses Flashcards
HIV
human immunodeficiency virus
AIDS
acquired immune deficiency syndrome
Impact of HIV/AIDS on immune system
Gradually destroys the sufferers immune system
How did HIV reach humans?
chimpanzees
Jumped the species barrier
Methods of HIV transmission
sexual contact, blood to blood contact, sharing of needles, from mother to child
Symptoms of HIV
Fever, weight loss, night sweats, diarrhea, fatigue
Symptoms of AIDS
unexplained weight loss, rare forms of pneumonia, rare cancers and infections not found in healthy human populations
Reverse transcriptase
a polymerase that catalyzes the formation of DNA using RNA as a template
How does HIV infect host cells?
Can’t replicate on its own so uses the cells’ biochemical mechanisms to produce parts needed for new HIV
How does HIV replicate?
- virus fuses with cells plasma membrane
- reverse transcriptase synthesises dna to rna
- second strand is synthesised by reverse transcriptase to be complementary
- double strand is incorporated as provirus is cell’s dna
- proviral gene transcribed into rna
- rna transcriped as mrna
- capsids assemble around viral genomes
- new viruses bud off from host cell
How does HIV target the Helper T Cells?
The GP120 binds to CD4 molecule on surface of helper T cells. This interferes with the T cells normal functioning
What impact would fewer helper T cells have?
B cells cannot stimulate antibodies or cytotoxic T cells. Also impacts memory cells. This causes an inadequate immune response
What is AIDS classified as?
A secondary illness
How do antibiotics work?
Damage the bacterial cells without damaging your own cells
Inhibit enzymes that synthesise bacterial cell walls
Enzymes are responsible for the formation of peptide cross eukaryotes
The weakening of the cell walls makes it unable to withstand pressure and causes them to burst- bacterium dies
