Cells- Immunity And HIV Flashcards
What is active immunity?
The production of antibodies by the immune system due to the presence of an antigen.
What is passive immunity?
Immunity aquired without an immune response.
Give examples of natural active and natural passive immunity.
Natural active immunity- Exposure to an antigen.
Natural passive immunity- Antibodies aquired through the placenta and breast milk of the mother.
Give examples of active artificial immunity and passive artificial immunity.
Active artificial immunity- vaccines stimulating the immune system to produce antibodies.
Passive artificial immunity- injection of antibodies into the body
What are vaccines?
The injection of dead or inactive pathogen in order to stimulate an immune response and create memory cells.
What are the factors affecting the success of a vaccine program?
- Cost of the vaccine
- Severity of the side effects
- Ease of production, transportation and administration.
- Number of people who need to be vaccinated for herd immunity.
What is herd immunity?
The number of vaccinated people in the population means the pathogen can’t be transmitted, so those who are vaccinated protect those who are unvaccinated.
Why are vaccines not always useful in preventing a disease outbreak?
The antigens on a pathogens surface can change, removing immunity
What are the ethical considerations of vaccines?
- Production and testing of vaccines may be done on animals.
- The risks of the vaccines must be balanced with the benefits.
- The vaccine must be tested on humans first to determine toxicity.
- Vaccinations are very expensive.
- Should vaccines be compulsory?
Name and describe the uses of monoclonal antibodies.
Direct therapy- Monoclonal antibodies that are specific to cancerous cells can be used to target and destroy these cells.
Indirect therapy- Drugs can be attached to monoclonal antibodies so the drug can be directed towards specific cells.
Diagnosis- Can be used to measure levels of an antigen in the body.
What is the structure of HIV?
A lipid envelope with embedded attachement proteins, surrounding a protein capsid where RNA and reverse transcriptase are present.
Describe the process of the replication of HIV.
- HIV binds to the CD4 protein commonly found on T helper cells.
- The capsid then fuses with the cell surface membrane.
- The RNA and reverse transcriptase enter the cell.
- The reverse transcriptase converts the RNA to DNA, which moves into the nucleus of the cell.
- The cell produces viral HIV components, taking sections of its cell membrane to produce HIV.
What is the process of an ELISA test?
- Coat a well with antigens
- Add the specific antibody to be measured.
- Add an enzyme-conjugated secondary antibody.
- Add substrate and measure colour.
Why are antibiotics ineffective against viruses?
They work by preventing bacteria from making cell walls.
However, viruses reproduce within a host cell so this doesn’t affect them.
