Module 1

Question 1

What is Microbiology?

Answer 1

study of all living microscopic organisms that are too small to be seen with the naked eye

Question 2

Zoonosis

Answer 2

Transmission of disease from animal or animal products to humans

Question 3

SARS

Answer 3

Severe acute respiratory syndrome

pneumonia like illness
Caused by corona virus

Question 4

MERS/CoV

Answer 4

Middle Eastern Respiratory Syndrome - Corona Virus

Similar to SARS, but high mortality rate

Question 5

Hendra Virus

Answer 5

Australia based virus found in horses

Transmitted to humans via close contact with infected bodily fluids

Question 6

TUberculosis

Answer 6

Single greatest cause of death due to infection

Multi-drug resistant

Question 7

Bacteria External Structures - Glycocalyx

Answer 7

Slime layer, prevents cells from drying out
Helps with attachment to hosts
Helps prevent host phagocytosis

Question 8

Bacteria External Structures - Endospores

Answer 8

Allows bacteria to live in harsh conditions

Surrounded by a spore coat, providing protection

Question 9

Gram Staining

Answer 9

Stains bacterial cell wall

Crystal Violet (purple) (Gram-Positive)
Iodine
Alcohol decolorisation
Application of safranin (Pink) (Gram-Negative)

Question 10

Difference between Gram Positive and Negative

Answer 10

Gram Positive Stains Purple (thick layer of peptidoglycan)

Stained by crystal violet due to defined cell wall
Consists of peptidoglycans and complex polysaccharides (teichoic acids)
NAG and NAG (disaccharides) that are cross linked and linked to the peptidoglycan by teichoic acids

Gram Negative Stains Pink (safranin) (thin layer)

Thin layer of peptidoglycan, covered by outer membrane
Outer membrane acts as a barrier for entry of foreign substances,

Produces LIPID A (endotoxin) which causes majority of the toxic effects when an infection has been established

Question 11

Difference Between Aerobic, Anaerobic, Obligate Aerobe, Obligate anaerobes, facultative anaerobes

Answer 11

Aerobic - Requires oxygen to grow
Obligate aerobic - same as aerobic
Anaerobic - does not require oxygen to grow
Obligate anaerobes - Killed in the presence of oxygen
Facultative Anaerobes - able to grow in either states

Question 12

How to differentiate between aerobe and anaerobe (which test is used?)

Answer 12

catalase test

Question 13

Generation Time

Answer 13

Time taken for a cell to reproduce

Question 14

The 4 growth phases of Bacteria (what do each represent)

Answer 14

Lag phase (period where microbe adapts to new environment)

Log phase (duplication and replication. [binary fission]

stationary phase (accumulation of waste product, as all the nutrients is used)

Decline phase (as density increases, oxygen levels decrease) (rate of cell division will stop and cells behind to die)

Question 15

Can Viruses Grow without a Host

Answer 15

As they lack most enzymes required for metabolism, they rely on hosts metabolism for growth.

Question 16

What makes up a virus

Answer 16

Either DNA or RNA
Can be single or double stranded
Enclosed in Capsid and sometimes also a outer envelope

Question 17

How does influenza enter the host

Answer 17

Is a Virus

Enters via glycoprotein spikes to attach to surface cell receptors of the respiratory epithelium (URTI)

Question 18

naked viruses are?

Answer 18

viruses that lack an envelope

More resistant to environmental conditions, as the envelope is sensitivity and can easily be damaged

Question 19

Virus Host Range

Answer 19

Very specific and usually only targets 1 animal or plant

Question 20

Tissue Tropism

Answer 20

When viruses attack only 1 specific kind of tissue/cell within the organism.

Question 21

6 Steps of Viral Replication

Answer 21

1. Adsorption
   virion attaches to surface receptor on the outside o the host cell
2. Penetration
   Once the virion is attached, the whole virion enters in 1 of 3 ways
   (direct penetration, membrane fusion, phagocytosis)
3. Uncoating
   virus is demantled, capsid and envelope is removed and broken down into amino acids and the nucleic acid is released into the cytoplasm
4. Synthesis
   Nucleic acid of the virus is copied multiple times producing viral mRNA and new viral capsid protein and enzymes
5. Assembly
   viral nucleic acid and synthesised capsomeres are assembled in the nucleus for DNA viruses and cytoplasm for RNA virus
6. Release
   Naked viruses are released from host cell, usually by cell lysis or death
   Enveloped viruses bud out of the cell membrane

Question 22

Prodromal Period

Answer 22

Period before clinical symptoms show

Also the period where it is most transmissible to others