Infectious agents

Question 1

What are the main types of infectious agents causing disease in humans?

Answer 1

Viruses
Bacteria
Fungi
Protozoa
Helminth

Question 2

Example of a virus and how it replicates

Answer 2

Replicates using host cell synthetic material

e.g. HIV, a retrovirus converted to DNA via reverse transcriptase

Question 3

Exmaple of a bateria and how it replicates

Answer 3

Divide via binary fission

e.g. Shigella - faecal-oral transmission

Question 4

Distinguishing features of a virus

Answer 4

Acellular

Obligate parasite

Question 5

Distinguishing features of a bateria

Answer 5

DNA chromosome
No nucleus
Prokaryotic

Question 6

Distinguishing features of a fungi

Answer 6

Single celled eukaryote

Occur as yeasts/filaments/both

Question 7

Example of a fungi and how it replicates

Answer 7

Yeasts bud
Hyphae form in filaments
E.g. Candida albicans - fungal infection

Question 8

Distinguishing features of a protozoa

Answer 8

Single celled eukaryote

May have complex life cycles with multiple hosts

Question 9

Example of a protozoa and how it replicates

Answer 9

Replicate by binary fission or by formation of trophozoites

e.g. Plasmodium spp. - causes malaria

Question 10

Distinguishing features of a helminth

Answer 10

Multicellular eukaryote
Visible to naked eye
Complex life cycles

Question 11

Example of a helmith and how it replicates

Answer 11

Asexual or sexual reproduction

e.g. Roundworm - transmitted by faceal-oral transmission, causes blockages and affects immunity and growth