Infection and Immunity

Question 1

Major Historical Milestones:
When did the Black death and White death occur?

State name of Disease, pathogen, and time (3)

Answer 1

Black death - Yersinia Pestis, killed 1/3 of Europeans 16th-17th Century

White Plague - Tuberculosis (mycobacterium tuberculosis), killed 1:4 UK population in 18th and 19th Century

Question 2

Who proved that germs are linked to diseases? (2)

Answer 2

Robert Koch (Nobel Prize 1905)

• Proved Mycobacterium tuberculosis caused TB
• Proved Bacillus Anthracis caused Anthrax

Question 3

What are Koch’s Postulates? (4)

Answer 3

1. A specific microorganism is always associated with a given disease.
2. Microorganism can be isolated from sick animal and grown in culture in a lab.
3. The cultured microbe will cause disease when inserted into healthy animal.
4. The same type of microorganism can be isolated from the newly sick animal.

Question 4

What are bacteria? Give some examples (3)

Answer 4

Bacteria are small, single celled prokaryotic organisms. They divide by binary fission and may have flagella.

e.g S. aureus, E.coli, mycoplasma etc.

Question 5

What are viruses? (3)

Answer 5

Viruses are particles of DNA/RNA in a protein coat, may have a lipid capsule.

They are not living cells and can only replicated in living cells.

Question 6

What are fungal pathogens? Give Examples (3)

Answer 6

Eukaryotic Fungus that can cause disease.

• Candida Species (albicans) Unicellular yeast and reproduce by budding.
• Aspergillus Species (e.g Fumigatus). Multicellular mould that reproduce by spores.

Question 7

What are other examples of pathogens? (2)

Answer 7

1. Protozoa - unicellular eukaryotic parasites e.g Plasmodium Falciparium (malaria)
2. Helminths - unicellular eukaryotic parasites, normally worms e.g Loa loa (African eyeworm); Taenia Saginata (beef

Question 8

What is an Antigen? (1)

Answer 8

Any substance that makes the body produce an immune response

Question 9

What are the characteristics of the immune system? (3)

Answer 9

1. It has memory
2. It is antigen specific
3. It is tolerant to things that are not harmful

Question 10

What are examples of when immune tolerance goes wrong?

Answer 10

Breakdown in tolerance leads to:
1. Allergy
2. Autoimmunity
Breakdown in immunity leads to:
3. Acquired or Genetic Immunodeficency