14.5 Flashcards
(19 cards)
What is immunity? (1)
It’s the ability of an organism to resist infection
Define what passive immunity is & Describe how passive immunity is achieved. (4)
(1) the introduction of antibodies into individuals from an outside source.
(2) No direct contact with the pathogen or its antigen is necessary to induce immunity.
(3) Immunity is acquired immediately.
(4) Because the antibodies are not being produced by the individuals themselves, the antibodies are not replaced when they are broken down, no memory cells are formed, and so there is no lasting immunity
Describe what active immunity is & how it works & its 2 types. (5)
(1) It is when you stimulate the production of antibodies by the individual’s own immune system.
(2) Direct contact with the pathogen or its antigen is necessary.
(3) Immunity takes time to develop.
(4) it’s generally long lasting.
(5) its two types: natural & artificial
Describe what Natural Active Immunity is. (2)
(1) It is when an individual is infected with a disease under normal circumstances.
(2) the body produces its own antibodies and may continue to do so for many years.
Describe what Artificial Active Immunity is. (2)
(1) It forms the basis of vaccination (immunisation).
(2) it involves inducing an immune response in an individual without them suffering the symptoms of the disease.
What is the contents of a vaccine? (1)
it contains a dead or weakened version of a pathogen or its antigens
How do vaccinations help overcome infections faster? (3)
(1) memory cells are produced,
(2) so they remain in the blood & allow a greater, & more immediate, response to a future infection with the pathogen.
(3) as a result, there’s a rapid production of antibodies & the new infection is rapidly overcome before it can cause harm.
Vaccinations are used as a ______(1)______ measure to ___(2)____ individuals contracting a disease.
(1) precautionary
(2) prevent
What are the features of a successful vaccination programme? (5)
(1) a suitable vaccine must be economically available in sufficient quantities to immunise MOST of the vulnerable population
(2) there must be few, if any, side effects from the vaccination.
(3) there must be means of producing, storing, & transporting the vaccine.
(4) there must be means of administering the vaccine properly at the appropriate time (involves training staff)
(5) it must be possible to vaccinate the vast majority of the vulnerable population to produce herd immunity
How does herd immunity arise? (2)
(1) when a sufficiently large population of the population has been vaccinated,
(2) which makes it difficult for a pathogen to spread within that population
Where the vast majority of the population is immune, it is highly _____(1)_____ that a susceptible individual will come in contact with an ____(2)____ person. In this way, those individuals who are not immune to the disease are nevertheless ____(3)____.
(1) improbable (or unlikely)
(2) infected
(3) protected
Why is it best to carry out vaccination programmes at 1 time? (2)
(1) because for a certain period, there are very few individuals in the population with the disease,
(2) so the transmission of the pathogen is interrupted
Why is herd immunity important? (1)
because it’s never possible to vaccinate everyone in a large population
Why may vaccinations not eliminate a disease? (6)
(1) vaccination fails to induce immunity in certain individuals, such as people with defective immune systems
(2) individuals may develop the disease immediately after vaccinating, but before their immunity levels are high enough to prevent it. So they can harbour the pathogen & reinfect others
(3) The pathogen may mutate frequently, so that its antigens change suddenly rather than gradually…
(4) there may be so many varieties of a particular pathogen that it’s almost impossible to develop a vaccine that’s effective against them all
(5) certain pathogens ‘hide’ from the body’s immune system e.g. viruses
(6) individuals may have objections to vaccination for religious, ethical or medical reasons
If a pathogen frequently mutates, how can that affect the effectiveness of the vaccine? (3)
(1) when they mutate, their antigens suddenly change (antigenic variability),
(2) which means that vaccines become ineffective because the new antigens on the pathogen are no longer recognised by the immune system
(3) so the immune system doesn’t produce the antibodies to destroy the pathogen & the individual remains infected.
Vaccinations do raise ethical issues that need to be addressed.
What ethical questions must be addressed that involve the production & use of vaccines? (5)
Any 5 of:
(1) How acceptable is it to use animals during the production of vaccines?
(2) How can the risk of side effects be balanced against the risk of developing a disease that causes even greater harm?
(3) On whom & how should vaccines be tested?
(4) Is it acceptable to trial a new vaccine with unknown health risks only in a country where the targeted disease is common, on the basis that the population there has most to gain if it proves successful?
(5) Is it right that vaccination should be compulsory?
(6) Should expensive vaccination programmes continue when a disease is almost eradicated?
(7) How can any individual health risk from vaccination be balanced against the advantages of controlling a disease for the benefit of the population at large?
NOTE: when discussing ethical issues, always present a balanced view that reflects both sides of the debate, & support your arguments with relevant biological information.
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Distinguish between active & passive immunity. (2)
(1) A : individuals are stimulated to produce their own immunity
P : antibodies are introduced from outside rather than being produced by the individual.
(2) A : immunity is normally long-lasting
P : immunity is normally short-lived
Explain why vaccinating against influenza is not always effective, given that it displays antigen variability. (2)
(1) its antigens change frequently & so antibodies no longer recognise the virus
(2) new vaccines are required to stimulate the production of antibodies that complement the new antigens
