L05: Nature And Properties Of Micro-organisms Flashcards
List the known micro-organisms
Prions
Virus
Bacteria
Fungi
How do prions work to cause infection
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
What disease can prions cause
CJD (creutzfeldt-Jakob disease) from mad cow disease
How does CJD occur in humans
Mad cows eat other dead’s cows brain which has prions
Human then eat the mad cow.
Is there any treatment to CJD
No
What are the features of a virus
Dna or Rna
Envelope with glycoproteins
How do viruses cause infection
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.
What are the effects of a virus
degeneration Proliferation Lysis Transformation Latent infection- for ageing people as their immune system declines
What disease does the varicella zoster virus cause
Chickenpox and shingles
What is shingles
The reactivation of varicella zoster virus in adults who have had chickenpox in childhood (latent infection)
What does Ebola virus cause
Haemorrhaging fever
What does Zika virus cause
Gillian barre syndrome
What are the 3 types of bacteria
Obligate
Opportunistic
Commensals
What is obligate bacteria
Bacteria that is always pathogenic and are obligated to infect you
What are opportunistic bacteria
Helpful bacteria but if it finds an opportunity it will infect you
What is commensals bacteria
Good bacteria that is never pathogenic
What are the features of a bacteria
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
What is the role of flagella
Makes bacteria move
What is the role of pili
Allows bacteria to attach to cells better
What is the role of the capsule
Makes bacteria more infectious as macrophages are less likely to kill them
What are the role of toxins
Kill cells
What are the 2 ways bacteria are classified
Gram negative
Gram positive
What is gram positive
Has one single membrane from peptidocyglan
What is gram negative
Double membrane
How do bacteria cause disease
Production of toxins
Tissue damage
Immune response by host activity
What other components does gram negative have on their cell wall
Lipopolysaccharides
What does lipopolysacharides cause
Sepsis
What same component does both gram positive and gram negative bacteria have on their cell wall
Peptidocyglan
Why is peptidocyglan important in clinical practice
It is a target for penicillin antibiotics
What other cell wall component does gram positive have
Lipoteich acid
What does lipoteichoic acid do
Septic shock
What colour does gram positive stain
Purple
What colour does gram negative stain
Pink
What are the features of fungi
Chitin wall
Single or multicellular cells
Hyphae which are cylindirical tubes that interconnect or form a mycelium(more fungi)
What is a common fungal infection
Thrush causes by Candida albicans in oral fungal infection
How do we classify viruses
Using the Baltimore scheme
