AIDS (AQA A Level Biology): Revision Note

AIDS

Symptoms of AIDS

• HIV infection often causes mild flu-like symptoms initially

• A latent period follows, with no obvious symptoms

• Over time, HIV becomes active, destroying helper T cells

• Fewer T cells weakens the specific immune response:

  • Reduced B cell activation, antibody production, and phagocytosis

• When the immune system can’t respond to pathogens, the person develops AIDS

• Opportunistic infections (e.g. TB) can then occur and can be fatal

Treatment of AIDS

• There is currently no cure for AIDS, but antiviral drugs can slow virus replication

• With treatment, HIV-positive individuals can have a normal life expectancy

Antibiotics and viruses

• Antibiotics kill bacteria by disrupting metabolism or protein synthesis

• Viruses are not cells as they lack metabolism and the cellular structures targeted by antibiotics

• Therefore, antibiotics are ineffective against viruses like HIV