Biology- Infection and response

Question 1

What is a communicable disease

Answer 1

A disease that can be spread from one person to another

Question 2

State the 4 types of pathogens

Answer 2

Virus, bacteria, fungi, protist

Question 3

What are the 3 examples of viral diseases

Answer 3

• Measles
• HIV
• Tobacco mosaic virus

Question 4

Measles: how its spread, treated and the symptoms

Answer 4

• Spread via droplets from an infected person’s sneeze or cough.
• treated through vaccination at young age
• symptoms include, red skin rash and signs of a fever
• Can be fatal (with complications)

Question 5

HIV: how its spread, treated and symptoms

Answer 5

• Spread by sexual contact or exchanging bodily fluids (sharing needles)
• Treated by antiretroviral drugs if found early enough (stops virus replicating)
• Symptoms: flu-like
• Virus attacks immune system- AIDS

Question 6

TMV: how its spread, treated and symptoms

Answer 6

• Spread by direct contact
• Can’t be treated
• Symptoms: mosaic pattern on leaf, parts of leaf discoloured
  —> discolouration means that plant cant carry out photosynthesis- so affects growth

Question 7

How do pathogens spread?

Answer 7

• Air, tiny droplets that we cough or sneeze. E.g. Measles, influenza
• Contaminated water, cholera - bacterial, drinking water that has been contaminated by diarrhoea of someone already suffering from cholera
• Contaminated food- E.g. Salmonella
• Direct contact, E.g Athletes foot, skin on feet flake off- walking barefoot on contaminated surfaces

Question 8

How do you stop pathogens spreading?

Answer 8

• Hygiene- washing hands, cleaning cookery items
• Kill the vectors (organisms that transport pathogens) e.g malaria- mosquitos
• Vaccination - can’t catch adisease (can’t pass it on)
• Isolate /quarantine (no contact)