MODULE 7: Infectious Diseases

Question 1

Define pathogen

Answer 1

A biological agent that causes disease or illness in a host organism

Question 2

Explain how pathogens cause infectiouse diseases

Answer 2

They live and reproduce at the expense of the host organism and cause disease by releasing toxins, damaging tissues or competing for nutrients

NOTE: presence of a pathogen does not always result in infection, requires host response

Question 3

Explain how infection occurs

Answer 3

Infection requires the pathogen to invade host cells, reproduce and elicit a host response

Question 4

List the type of pathogens

Answer 4

Microscopic: cellular pathogens (prokaryotic: bactiera, eukaryotic: fungi and protozoa)
non-cellular pathogens (proteins:prions, protein coat:virus)

Macroscopic: endoparasites and ectoparasites

Question 5

Classify bacteria

Answer 5

• unicellular prokaryote
• do not have membrane bound organelles
• has a cell wall
• circular chromosomes
• reproduces by binary fission