L05: Nature And Properties Of Micro-organisms

Question 1

List the known micro-organisms

Answer 1

Prions
Virus
Bacteria
Fungi

Question 2

How do prions work to cause infection

Answer 2

1) the mutated prion (bad) called prPsc converts the good normal prion protein to misfold.
2) the normal protein is now misfolded to build up
3) build up of protein forms amyloid fibres which lay down on the brain to cause degenerate

Question 3

What disease can prions cause

Answer 3

CJD (creutzfeldt-Jakob disease) from mad cow disease

Question 4

How does CJD occur in humans

Answer 4

Mad cows eat other dead’s cows brain which has prions

Human then eat the mad cow.

Question 5

Is there any treatment to CJD

Answer 5

No

Question 6

What are the features of a virus

Answer 6

Dna or Rna

Envelope with glycoproteins

Question 7

How do viruses cause infection

Answer 7

Viruses Bind to the cell receptor by their glycoproteins on envelope
Virus is endocytosed
Envelope is removed to release viral nucleic acids
Viral Rna is replicated, transcribed and translated
New protein is formed
New virus is assembled and released from the cell.

Question 8

What are the effects of a virus

Answer 8

degeneration 
Proliferation
Lysis 
Transformation 
Latent infection- for ageing people as their immune system declines

Question 9

What disease does the varicella zoster virus cause

Answer 9

Chickenpox and shingles

Question 10

What is shingles

Answer 10

The reactivation of varicella zoster virus in adults who have had chickenpox in childhood (latent infection)

Question 11

What does Ebola virus cause

Answer 11

Haemorrhaging fever

Question 12

What does Zika virus cause

Answer 12

Gillian barre syndrome

Question 13

What are the 3 types of bacteria

Answer 13

Obligate
Opportunistic
Commensals

Question 14

What is obligate bacteria

Answer 14

Bacteria that is always pathogenic and are obligated to infect you

Question 15

What are opportunistic bacteria

Answer 15

Helpful bacteria but if it finds an opportunity it will infect you

Question 16

What is commensals bacteria

Answer 16

Good bacteria that is never pathogenic

Question 17

What are the features of a bacteria

Answer 17

Rigid cell wall made of peptidocyglan
If gram negative they have an extra phospholipid membrane surrounding peptidocyglan
If gram positive they don’t have extra phospholipid membrane
Flagella
Pili
Capsule
Toxins

Question 18

What is the role of flagella

Answer 18

Makes bacteria move

Question 19

What is the role of pili

Answer 19

Allows bacteria to attach to cells better

Question 20

What is the role of the capsule

Answer 20

Makes bacteria more infectious as macrophages are less likely to kill them

Question 21

What are the role of toxins

Answer 21

Kill cells

Question 22

What are the 2 ways bacteria are classified

Answer 22

Gram negative

Gram positive

Question 23

What is gram positive

Answer 23

Has one single membrane from peptidocyglan

Question 24

What is gram negative

Answer 24

Double membrane

Question 25

How do bacteria cause disease

Answer 25

Production of toxins Tissue damage Immune response by host activity

Question 26

What other components does gram negative have on their cell wall

Answer 26

Lipopolysaccharides

Question 27

What does lipopolysacharides cause

Answer 27

Sepsis

Question 28

What same component does both gram positive and gram negative bacteria have on their cell wall

Answer 28

Peptidocyglan

Question 29

Why is peptidocyglan important in clinical practice

Answer 29

It is a target for penicillin antibiotics

Question 30

What other cell wall component does gram positive have

Answer 30

Lipoteich acid

Question 31

What does lipoteichoic acid do

Answer 31

Septic shock

Question 32

What colour does gram positive stain

Answer 32

Purple

Question 33

What colour does gram negative stain

Answer 33

Pink

Question 34

What are the features of fungi

Answer 34

Chitin wall Single or multicellular cells Hyphae which are cylindirical tubes that interconnect or form a mycelium(more fungi)

Question 35

What is a common fungal infection

Answer 35

Thrush causes by Candida albicans in oral fungal infection

Question 36

How do we classify viruses

Answer 36

Using the Baltimore scheme