The human immunodeficiency virus Flashcards
Structure of the human immunodeficiency virus (HIV)
+Lipid envelope
+Attachment proteins- embedded in lipid envelope
+Capsid- protein layer
+RNA- 2 strands enclosed by capsid
+Reverse transcriptase- catalyses the production of DNA from RNA, enzyme
HIV is group of viruses= retroviruses
Replication of the human immunodeficiency virus
+HIV enters the bloodstream and circulates around the body
+A protein on HIV binds with CD4. Most frequently attaches with helper T cells
+The capsid fuses with the membrane and the RNA, enzymes enter T cell.
+The transcriptase converts the RNA to DNA
+This DNA is moved into the cells nucleus and is inserted into the cell’s DNA
+The HIV DNA creates mRNA using the cells enzymes. It contains the instructions to make new viral proteins and the RNA go into the new HIV.
+The mRNA goes through a nuclear pore and use the cells protein synthesis to make HIV particles.
+The HIV particles break away from the cell with a piece of membrane which forms the lipid envelope.
How HIV causes the symptoms of AIDS.
+The HIV attacks hT cells.
+It causes AIDS by interfering with the function of it .
+Normal person= 800-1200 hT cells. on mm3
+Infected person ≈ 200
+ With low cells immune system can’t stimulate B cells or cytotoxic T cells
+ Can infect or damage memory cells.
+ ∴ body is susceptible to infections and cancers
+ Infected develop infections in lungs, intestines, brain and eyes. These result in death.
The ELISA test
Procedure
Enzyme linked immunosorbant assay
+Used to detect the presence of the protein and the quantity.
1.Apply the sample to a surface, for example a slide, to which all the antigens in the sample will attach
2.Was the surface several times to remove any unattached antigens
3.Add the antibody, that is specifc to the antigen we are trying to detect and leave the two to bind together
3. Wash the surface to remove excess antibody
4.Add a second antibody that finds with the first antibody(@nd AB has enzyme attached to it)
5.Add the colourless substrate of the enzyme. The enzyme acts on the substrate to change it to a coloured product
6. The amount of antigen present is relative to the intensity of the colour that develops.
Why antibodies are ineffective against viral diseases like AIDS?
+Antibiotics inhibit the synthesis and assembly of the peptide cross linkages in Bac cell walls
+ ∴, the cell wall bursts.
+Viruses lack metabolic c structures
+Have.a protein coat rather than murein in BAC
+When in organisms’ own cells, antibiotics can’t reach them.
