Unit 3: Chapter 11 - Specific Resistance To Infection

Question 1

Immunisation

Answer 1

Programming the immune system so the body can response rapidly to pathogens
Occurs artificially or naturally

Question 2

Vaccination

Answer 2

The artificial introduction of antigens of of pathogenic organisms so the person can produce the appropriate antigens without having to experience the disease.

Question 3

Vaccine

Answer 3

The antigen preparation used in artificial immunisation.
There are four types:
Attenuated - microorganisms with reduced virulence, can’t produce disease symptoms
Dead microorganisms - immunity is not prolonged like the attenuated is.
Toxins from bacteria - in cases where bacteria produce toxins that cause effects, it’s not necessary to use live or dead bacteria for immunisation. Toxoids: toxins that are inactivated, so they do not make you ill
Sub-unit vaccine - a fragment of the microbe is used to provoke immune response.

Question 4

Recombinant DNA methods (creating vaccines)

Answer 4

To produce less side-effects and longer-acting vaccines, manufacturers can modify the DNA of organisms to be less virulent, or insert DNA sequences (for production of antigens) from pathogens into harmless bacteria cells.

Question 5

Herd immunity

Answer 5

When there are a large number of immune individuals in a population, there is less chance of the disease being transmitted between them.
Mass immunisation programs have eradicated or greatly reduced incidence of disease.
Australia has an immunisation schedule for infants, children and adults – most diseases require more than 1 dose to activate enough B-Cells to produce antibodies. Waiting period is to ensure antibodies are eliminated in blood before antigen is introduced again.
Vaccination doesn’t start until newborns are older than 2 months, otherwise they still have mothers antibodies and it is not effective.

Question 6

Antibiotics

Answer 6

Drugs used to fight infections of microbes, particularly bacteria.
Not used for viruses.
Each type of antibiotic is specific to a certain type(s) of bacteria
Broad spectrum offer wide range
Narrow spectrum are very specific
There are 2 types of antibiotics

Question 7

Bactericidal antibiotics

Answer 7

They kill bacteria by changing structure of wall or membrane

Question 8

Bacteriostatic antibiotics

Answer 8

Stop reproduction of bacteria

Streptomycin - interfere with protein synthesis, therefore cell reproduction

Question 9

Antibiotic resistance

Answer 9

The widespread use of antibiotics in medicine and agriculture has lead to bacteria evolving resistance.
If resistance to many different antibiotics, infection is known as multiple drug resistance = super bugs
If resistance to all antibiotics known, they have total drug resistance
Solve by developing new antibiotics, synthesising old antibiotics with new/other substances, genetically engineering bacteria to disable antibiotic-resistant genes

Question 10

Antivirals

Answer 10

Drugs used to treat viral infections. Inhibit the development of the virus
Problems: Any drug that interferes with viral replication will hurt the host cells, as this is where new virus particles are made
Solution: determine genetic sequence of viruses to identify proteins that can be disabled by particular chemicals. If the proteins are different to human cells, it should work without side-effects.