Infection S1 - Introduction

Question 0

How may viruses be classified?

Answer 0

They are either made up of DNA or RNA

Question 1

List the types of microorganism which can cause human disease

Answer 1

Bacteria
Viruses
Fungi
Parasites
(Prions)

Question 2

How are DNA viruses further categorised?

Answer 2

As single stranded or double stranded

Then as enveloped or non-enveloped

Question 3

How are RNA viruses further categorised?

Answer 3

As single or double stranded
As positive or negative strands
As enveloped or non-enveloped
As helical or icosahedral

Question 4

What are bacteriophages and why are they clinically relevant?

Answer 4

They are viruses which infect bacteria. Relevant because they can affect how virulent a bacterial infection can be

Question 5

What shapes can bacteria be?

Answer 5

Cocci (round)
Bacilli (rods)
Spirilli (spirals)

Question 6

How are cocci colonies arranged? Name examples of bacteria

Answer 6

In clusters eg staphylococcus

In chains eg streptococcus

Question 7

State how gram staining classifies bacteria and how this is clinically relevant

Answer 7

The gram test stains the thick peptidoglycan wall of gram positive bacteria purple and the thin peptidoglycan wall of gram negative bacteria red.
Relevant because some antibiotics work better on gram positive bacteria than negative and vice versa

Question 8

Define aerobic bacteria

Answer 8

Aerobic bacteria can survive in the presence of oxygen

Question 9

Define obligate aerobes

Answer 9

Bacteria which require oxygen to survive

Question 10

Describe anaerobes

Answer 10

Can survive an absence of oxygen

Question 11

Describe obligate anaerobes

Answer 11

Bacteria which require the absence of oxygen for survival

UNLESS they are able to form spores (spores are seriously tough shit)

Question 12

What are the mechanisms of bacterial pathogenesis?

Answer 12

>Virulence factors
-Host entry
-Adherence to host cells
-Invasiveness
-Iron sequestration
>Toxins
-Endotoxins
-Exotoxins

Question 13

What is the difference between endotoxins and exotoxins?

Answer 13

Exotoxins are toxic substances secreted by bacteria and released outside the cell, whereas Endotoxin is a lipopolysaccharide which the body is hypersensitive to (picomoles can be detected) which triggers fevers and hypotension

Question 14

What are the relevant classifications of fungi?

Answer 14

Single celled yeasts

Multicellular molds

Question 15

What are the relevant classifications of parasites?

Answer 15

Single called Protozoa

Multicellular worms