Disease and the immune system.

• Outline how to observe blood under a microscope?

  1)Smear a drop of blood onto a slide using a spreader held at 45 degrees

  2)Add Leishman stain then a buffer. Rinse
• Why are there clear areas of agar in the petri dish?

  bacteria has been killed as it cannot grow in the presence of the antibiotic
• What is a multodisc?

  A petri dish containing different antibiotics
• Why might a hospital use a multodisc to select the most suitable antibiotic for treating a patient?

  1 it’s cheap

  2 the test is quick to carry out, as it involves testing several antibiotics at the same time

  3 allows early treatment of patients

  4 compares antibiotics under the SAME conditions
• Why may it become increasingly difficult to discover new drugs in the future?

  New drugs come from organisms such as plants, animals and fungi and as biodiversity is reducing due to habitat being destroyed due o deforestation there is less access to them.