what are micro organisms
organisms that are too small to be seen with the naked eye
2 types of microrganisms + examples
acellular - pirons / viruses
cellular - prokaryotic / eukaryotic
What type of microorganisms are classified as acellular?
Those unable to replicate on their own.
State 3 differences between a prokaryotic cell and a eukaryotic cell
Prokaryotic cells have no nucleus whereas eukaryotic cells do have a nucleus.
Prokaryotic cells have a single circular chromosome whereas eukaryotic cells have multiple linear chromosomes.
Prokaryotic cells have a plasmid where as eukaryotic cells have no plasmid
Prokaryotic cells have no membrane bound organelles whereas eukaryotic cells do have membrane bound organelles.
viruses
- not living
- not eukaryotic or prokaryotic
- can not carry out metabolic reactions on their own (need a host cell)
viruses - structure
1) naked
- nucleic acid enclosed in a protein coat (capsid)
2) enveloped
- have an additional outer layer
What is normal microflora?
organisms that live on or in the body but do not cause disease
What is the advantage of a virus being enveloped?
Helps adherence
What is an advantage of naked viruses?
More resistant to the environment
What are the three functions of viral capsid proteins?
- antigenic properties
- helps with attachment
- protects the nucleic acid against inactivation
Why do viruses need a host cell?
The don’t have the DNA to replicate
viral repication
- adsorption
- attachment of viral capsid on receptor site of host - penetration
- virus enters cell via direct penetration, membrane fusion and phagocytosis - uncoating
- capsid is removed so nucleic acid can be released - synthesis
- copying of the nucleic acid - assembly
- nucleic acid and capsid is assembled. The DNA goes to nucleus and the RNA to cytoplasm - release
- naked viruses = released from host cell resulting in cell lysis and death
- enveloped viruses = bud out through cell membrane acquiring their envelope which has been modified by the insertion of viral glycoprotiens
List 5 ways a virus can be transmitted
airborne, faecal-oral, bodily fluids, vectors, foetal and neonatal
What is a vector?
Mosquito
Which human based diseases are caused by viruses?
Glandular Fever, HIV, Chicken Pox, Hep and Herpes
latent viral infections
remain dormant in some host cells and can become reactivated later
chronic viral infections
virus remains in host cells - gives rise to continuous low level of viral production and shedding (carrier state)
oncogenic viruses
cause tumors
Why are antibiotics useless in fighting viral diseases?
viruses have a protective protein that antibiotics can’t attack
treatment of viruses
1) vaccines
2) antiviral medications
Where in the body does HSV type 2 infect?
usually genitals
occasionaly around skin of mouth
Where in the body does HSV type 1 infect?
usually around skin around mouth
occasionally genitals
What is vertical transmission?
mother to child
What is the transmission route for HPV?
direct contact
