Disease and Immunity

Question 1

What is a Pathogen?

Answer 1

A disease-causing organism

Question 2

What is a Transmissible disease?

Answer 2

a disease where the pathogen can be

Question 3

Diseases can be transmitted through direct and indirect contact. What does this mean? give examples.

Answer 3

Direct contact: through blood or other bodily fluids

Indirect contact: Contaminated surfaces, food, animals or the air

Question 4

What are mechanical and chemical barriers? give 2 examples for each.

Answer 4

Mechanical barrier: Provides a physical barrier,

• Nasal hairs in the nose trap and waft dirt and microbes away from the airway
• The skin

Chemical barrier: destroys pathogens

• Strong stomach acid kills pathogens
• Mucus contains anti-microbial chemicals

Question 5

What are 2 ways white blood cells protect the body from infection

Answer 5

• Phagocytosis (engulfing pathogens)

- Producing antibodies that attach to pathogens

Question 6

How do antibodies work?

Answer 6

• Lymphocyte makes antibodies which detect that the antigens are not from our body
• Antibodies could either attach to the pathogen to make it easier to be detected by Phagocytes (to be engulfed) or destroy the pathogen

Question 7

Why can antibodies only attach to certain antigens?

Answer 7

Because each antigen has a specific shape and can only bind to specific antibodies

Question 8

What is active Immunity?

Answer 8

Active immunity is where white blood cells produce a specific type of antibody for pathogens

Question 9

How can active immunity be obtained?

Answer 9

1. Vaccination: This is when you inject a harmless version of the pathogen, the white blood cells will detect the antigen and make specific antibodies to combat this.
   = If the person is exposed to the disease later, the white blood cells already know which type of antibody to produce (immune to disease).
   = Memory cells are made and produce more antibodies quicker than before so you don’t get sick.
   = this gives long term immunity
2. Infection by pathogen

Question 10

What are methods of controlling the spread of disease?

Answer 10

= Hygenic food preparation
= Good personal hygiene
= Waste disposal
= Sewage removal and taking precautions

Question 11

What is herd immunity?

Answer 11

When the vast majority of the population is vaccinated making it so that the disease spreads less

Question 12

What is passive immunity and why is it important for newborn babies?

Answer 12

• Short-term immunity by receiving antibodies from another individual.
• Only short term because no memory cells are produced
• It is important for infants because they have not had enough time to develop their own antibodies as they have not been exposed to as many pathogens yet

Question 13

What is autoimmune disease? give an example.

Answer 13

A disease where your immune system attacks the body cells, for e.g.
- Type 1 diabetes