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30 Cards in this Set
- Front
- Back
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What is active immunity? |
Where the immune system produces its own antibodies after being stimulated by an antigen/ |
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What is natural active immunity? |
This results from being infected by a pathogen under normal circumstances and the body produces its own antibodies. |
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What is artificial active immunity |
An immune response is induced e.g. vaccine |
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What is passive immunity? |
The introduction of antibodies to an individual from an outside source. The immune system doesn't produce any antibodies of its own |
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What is natural passive immunity? |
Antibodies from the mother are passed through the placenta or breast milk. |
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What is artificial passive immunity? |
Where the body is injected with antibodies e.g. tetanus |
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What are four facts about active immunity? |
It requires exposure to an antigen The immune response takes a while Memory cells are produced It provides long term immunity |
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What are four facts about passive immunity? |
It doesn't require exposure to an antigen There's immediate protection Memory cells aren't produced It provides short term immunity |
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What is a vaccination? |
Deliberate exposure to harmless antigenic material to activate an immune response and antibodies and memory cells which provide immunity. |
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What do vaccines do? |
They protect individuals that have them and because they reduce the occurrence of the disease, those not vaccinated are also less likely to catch the disease. This is called herd vaccination. |
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What are positives about vaccines? |
They protect the individual They reduce the chance of others getting the disease They may eventually eradicate the disease. |
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Why is it difficult to eradicate a disease with vaccinations? |
The vaccine may fail to provide immunity. The pathogen may mutate so its antigens change, the vaccine's no longer effective There may be different varieties of a pathogen People may object to vaccines due to religion, ethics or medical reasons |
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What is it called when the antigens of a pathogen change? |
Antigenic variation |
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What are the ethical problems with vaccines? |
They're tested on animals Human tests may be risky There may be side effects To be fully effective, the whole population must be vaccinated |
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What does HIV stand for? |
Human immunodeficiency virus ` |
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What does HIV lead to? |
AIDS |
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What does AIDS stand for? |
Acquired immune deficiency syndrome |
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What do AIDS and HIV affect? |
The immune system |
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What does AIDS cause? |
They immune system deteriorates and eventually fails so you are more vulnerable to other infections |
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What does HIV do? |
It kills helper T cells, which act as host cells for the virus. This prevents the immune system from responding effectively. Initially, it replicates rapidly and causes flu-like symptoms. After this, replication goes through a lower latency period and there are no symptoms |
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When does HIV turn into AIDS? |
When helper T cells reach critically low levels |
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What is step 1 of HIV replication? |
The attachment protein of the virus attaches to the receptor molecule on the cell membrane of the helper T cell. |
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What is step 2 of HIV replication?
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The capsid is released into the cell where it uncoats and releases its genetic material(RNA) into the cell's cytoplasm |
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What is step 3 of HIV replication?
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In the cell, reverse transcriptase is used to make a complementary strand of DNA from the viral RNA template |
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What is step 4 of HIV replication?
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From this, double stranded DNA is made and inserted into the human DNA |
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What is step 5 of HIV replication?
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Host cell enzymes are used to make viral proteins from the viral DNA found within the human DNA |
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What is step 6 of HIV replication?
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The viral proteins are assembled into new viruses, which bud from the cell and go on to infect other cells |
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What do antibiotics do? |
They kill bacteria by affecting the cell walls or DNA replication |
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How does penicillin affect the cell walls of bacteria? |
It inhibits certain enzymes required for the synthesis and assembly of peptide cross linkages in bacterial cell walls.This weakens the walls making them unable to withstand pressure. Water enters by osmosis, the cells bursts and the bacterium dies. |
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Why don't antibiotics affect viruses? |
Viruses replicate inside host human cells which antibiotics have no effect on |
