5.2 Pathogens and diseases

Question 1

What causes infectious disease?

Answer 1

microorganisms known as pathogens

Question 2

How do pathogens make you ill?

Answer 2

as a result of reaction to toxins produced,

or damage caused to cells

Question 3

How are diseases spread from one person to another?

Answer 3

. by air
• direct contact
• direct contact of body fluids
• by contaminated water
• by undercooked or contaminated food.

Question 4

How are diseases spread from one plant to another?

Answer 4

. by air
• direct contact
• by contaminated water

Question 5

Explain how pathogens are passed from person to another

Answer 5

by air- droplet infection: droplets full of pathogens expelled in coughing, sneezing, or talking, droplets breathed in by others,
• direct skin contact- pathogens spread from skin of one person to skin of another,
• direct contact of body fluids- pathogens pass directly from inside one person’s body into another,
• by contaminated water- taking in pathogen through digestive system,
• by undercooked or contaminated food- taking in pathogen through digestive system.

Question 6

Explain how pathogens are passed from plant to another

Answer 6

by air- fungal spores carried in air from one plant to another,
• by direct contact- pathogens on traces of plant material come into contact with new plants in the soil and infect them,
• by contaminated water- fungal spores carried in splashes of water from one plant to another

Question 7

Describe and explain the main differences between bacteria and viruses, and how they cause disease?

Answer 7

Bacteria are single-celled organisms much smaller than plant and animal cells.
Viruses are even smaller than bacteria.

Bacteria divide rapidly by splitting in two (binary fission).
Viruses take over body cells and reproduce inside them.

Bacteria may produce toxins or directly damage body cells.
Viruses damage and destroy cells.

Question 8

Main type of human pathogens are

pick two from - bacteria, viruses, protists, fungi

Answer 8

bacteria, viruses

Question 9

Main type of plants pathogens are

pick two from - bacteria, viruses, protists, fungi

Answer 9

viruses, fungi